Browsing by Author "Finnie, Jeffrey Franklin."

Now showing 1 - 20 of 53

Ameliorative effects of botanicals and rhizobacteria on the growth of Pelargonium sidoides and Solanum lycopersicum infested with Meloidogyne incognita.
(2021) Sithole, Nokuthula Thulisile.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Abstract available in PDF.
An analysis of differential tests as a predictor for learner performance in first year biosciences.
(2004) Finnie, Jeffrey Franklin.; Luckett, Kathleen Margaret.
This research project aims to establish the predictive validity of a set of aptitude tests for the first year Biosciences programme at a merging South African University. The study aims to address the problem of selection and placement to higher education and also to suggest how the results of aptitude tests might be used to inform curriculum development at first year level. The Differential Aptitude Test (DAT-L) was conducted on the 2004 Biosciences student cohort (228 students). The instructions that were given to the students followed the instructions laid out in Owen and Vosloo (1999). Normally there are ten tests in this battery of tests, however only eight of the tests were given to the students. The tests included; Vocabulary, Verbal reasoning, Non-Verbal reasoning: Figures, Calculations, Reading Comprehension, Comparisons, Price Controlling and Memory. Exam results of the participating students were collected. These included; Final Biosciences101 mark, Class mark (Biosciences101), Practical exam mark (Biosciences101) and Theory exam mark (Biosciences101). The final marks for Physics (mixed modules), Mathematics (mixed modules) Computer Sciences (CSCI 103) and Chemistry (CHEM131) were also collected. The indicator for the concept of academic potential in the Biosciences was taken as the marks achieved during the course of the first semester. Biographical information from the Student Management System (SMS) was also recorded this included; Race, Gender, Home language and Matric points. These various categories were compared against the students' performance in DAT-L tests. The average for the stanine points for a student of university "quality' is seven, according to Owen et al. (2000), while the average of this cohort of students is 5.16. The correlation for the different DAT tests when compared with the final result for Biosciences shows that the best correlation is with test 1 at r = .47292 (Vocabulary) while the worst correlation is with test 6 at r=.24722 (Comparison). The sequence of correlation is from Vocabulary through Reading Comprehension, Verbal Reasoning, Calculation, Memory, Price Controlling, Non-Verbal Reasoning: Figures, and finally Comparisons. The correlation of the average of all tests and the final result is a reasonable r = .50396. The best correlation with DAT and other subjects is Computer Science with r = .41165, with a declining correlation between Physics and the mark of r = .34085 followed by extremely poor correlations for Chemistry and Mathematics of r = .20313 and r = .08700 respectively. The best correlation that was obtained during this research was with the correlation between matric points and the average of all the DAT tests. While the correlation with DAT and the Final mark for Biosciences is r = .50396 that for the matric points is r = .57150. Females attained a significantly higher average on the DAT tests but the difference between female and male on their final results in Biosciences is not significant. White students perform significantly better than the other race designations when it comes to the final result. Within the categories African, Indian and Coloured there is no significant difference. When it comes to the different DAT tests, Africans perform significantly worse than the other three groupings and the Indian grouping did significantly worse when compared to Whites. If we were to use the DAT as a means of selecting students it would be fairly effective for biology but not for the other basic science subjects. The fact that the test would have to be administered to all applicants applying to do first year in the Science and Agriculture Faculty makes the choice of this set of tests questionable. Should the Faculty require a means of determining election into biological subjects then the tests show great promise. The pursuit of greater fairness, validity and reliability in selection is an ongoing quest.
Antidiabetic and phytochemical properties of four selected medicinal plants.
(2019) Ratsoma, Manchela Francinah.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Abstract available in pdf.
Biochemical, physiological and agronomic response of various sweet potato cultivars/varieties to drought stress in rainout shelters and field conditions.
(2014) Laurie, Robert Naylor.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Drought is and will always be an issue in the cultivation of plants. Some plants have the ability to withstand a drought conditions to a certain degree while others, with other useful attributes, fail dismally. The value of testing genotypes for the ability to tolerate drought cannot be underestimated and will enhance the progress in the selection of drought tolerant genotypes. Thus, the objective of this study was to investigate the physiological, biochemical and agronomical reaction of sweet potato plants to drought and the procedures which could be used to test for sweet potato drought tolerance in the field. This was made possible through the creation of an environment at ARC-Roodeplaat in which sweet potato plants could be subjected to drought stress conditions. Thirty five sweet potato genotypes were planted in three trials in rainout shelters and open fields to analyze their physiological, biochemical and agronomical responses to drought stress. The majority of the genotypes were selected breeding lines with some cultivars from America, Peru and South Africa. These genotypes were chosen due to their range of traits for incorporation in crosses in the sweet potato breeding programme of the Agricultural Research Council (ARC). Drought stress conditions on the plants were induced through selective irrigation practices. In Trial 1 control plants were cultivated at field capacity while drought stressed plants received 60% and 30% of the amount of water of the control, respectively. In Trial 2, genotypes were planted in the field and under rainout shelters respectively. The field plantings acted as the control and received normal rain and irrigation while the rainout shelter planting received irrigation corresponding to 30% of field capacity. The plants in Trial 3 were subjected to control and drought conditions with the drought stressed plants receiving 30% of the water of the control. Leaf harvesting and phenotypical measurements were conducted twice during the trial period i.e. 60 and 120 days after planting. The drought stress impacted the growth of the sweet potato plants significantly. Canopy cover and stem length were severely influenced by the drought stress and resulted in huge declines of the respective values in all trails. Canopy cover values declined by more than twice compared to the control while stem length values were reduced by up to 10 times compared to the control. Antioxidant systems with particular reference to ascorbate peroxidase (AP), super oxide dismutase (SOD) and glutathione reductase (GR) reacted to the stress imposed and increased significantly. It was observed that values of the respective antioxidant enzyme systems increased sharply in the latter part of the trial and that the increase was also more intense at severe stress. The analysis of the antioxidant system made it possible to distinguish between the genotypes regarding their reaction to the stress. Results for carbon discrimination experiments in all the trials indicated that a significant decline in values took place as the drought stress increased. The decline appeared to be slightly more pronounced as the stress progressed. Also, as in the case of the antioxidant systems, it was possible to distinguish between genotypes even in the control treatments. The plants responded to the drought stress to the effect that a similar trend, (compared to the antioxidants), was observed with regards to stomatal conductance although genotypical differentiation was not possible in any of the stress conditions. It was demonstrated in the trials that the relative water content (RWC) values in the leaves of plants subjected to drought stress declined significantly between water treatments. Drought stress in the three trials had a severe impact on the nitrate reductase (NR) activity in the leaves of the plants. The decline in values were substantial but no significant differences could be detected between the genotypes except for the breeding line 2005-1-16 and cultivars Purple Sunset, Beauregard and Zapallo. Slight non-significant differences were observed between the genotypes at mild stress conditions but the severe stress conditions proved too harsh. Significant increases in the proline content of the sweet potato plants subjected to drought stress resulted in differentiation between the genotypes in Trial 1 and Trial 2, especially during the latter stages of the trials and at severe stress. Large reductions, up to 97%, of root yield were detected in the three trials. It appeared that the severe stress treatment proved too harsh to accomplish significant differences between the genotypes in all the trials. In Trial 1 the genotype Resisto differed significantly from the other genotypes and seemed to tolerate the drought the best in the mild stress conditions. Water use efficiency (WUE) values did allow for discrimination between the genotypes in Trial 1. A large decline in WUE values were observed in Trial 2 in general, although a few breeding lines 2005-7-4, 2006-4-4 and ix 2006-7-7 were prominent with high WUE values and could be recommended for use in a breeding programme. In Trial 3 the cultivar Bophelo and 199062.1 also exhibited higher WUE values which correlate well with yield data obtained from the same Trial. This could also prove valuable in the selection process. Due to the fact that multiple traits make a valuable contribution to the decision-making process in the selection for possible screening methods, statistical correlation was undertaken to establish possible relationships between traits. Good correlation was found between yield, stomatal conductance and WUE in Trial 1. This confirmed the assumption that a drop in stomatal conductance will result in lower root yield. Proline correlated also very well with the antioxidant enzyme levels of GR and AP which indicates that while the antioxidant enzymes play a role in combatting oxidants proline aid in possible prevention of moisture loss and stabilization of cell membrane structures. In Trial 2 good correlation was observed between yield, LAI, NR and CCI and to a lesser extent carbon-13 discrimination. This confirmed the belief that a decrease in LAI and CCI should have a negative effect on the yield due to less canopy cover and less chlorophyll for the capture of sunlight for photosynthesis. Results from Trial 3 also indicated good relationships between proline, GR and AP, as well as good relationships between yield, WUE, carbon discrimination and stomatal conductance (gs). It can hereby be concluded that the reaction of sweet potatoes to drought stress revealed results that can be of help for use in the future to successfully establish a protocol whereby successful selection of genotypes can be made in a biochemical, physiological and agronomical way. The study also provided proof that some of the approaches and procedures used in these trials can be successfully implemented in the drought screening of sweet potato.
A comparative evaluation of the biological activities and phytochemical properties in Ehretia obtusifolia and Ehretia rigida.
(2021) Mnikathi, Mzamo Mpendulo Ntethelelo.; Finnie, Jeffrey Franklin.; Van Staden, Johannes.
Ehretia from the Boraginaceae family is predominantly found in parts of Asia and North America, with fewer species found in Africa, Europe, and Australia. The genus consists of more than 150 species, and species such as E. microphylla, E. accuminata, E. laevis have been reported on their medicinal prowess. Distribution of Ehretia in Southern Africa is found among a variety of habitats such as the lush forests of the Eastern Cape and Arid parts of Namibia. In South Africa, two species have been identified, namely E. rigida and E. obtusifolia and are used in traditional medicine. African and Asian countries traditional medicine is highly recommended because of its affordability. The aim of the study was to establish a baseline and compare different biological activities and phytochemical properties exhibited by the two South African species. In the study, phenolics, saponins, flavonoids, and tannins were detected in bark, roots, and leaves, of both species, but no detection of alkaloidsf. E. obtusifolia had a higher quantity of flavonoids than E. rigida. Both species exhibited high phenolic quantities in leaves with E. rigida having the highest quantity. Condensed tannins were found with a higher content in leaves than roots and bark for both species, with E. rigida containing higher quantities. E. rigida had the lower MIC’s compared to E. obtusifolia (0.195 mg/ml against M. luteus from ethyl-acetate root extracts). E. rigida had more samples with a MIC lower than 1 mg/ml than E. obtusifolia. The lowest MIC for leaves was 0.39 from ethyl-acetate extracts against S. aureus while methanol bark extracts also achieved 0.39 mg/ml against M. luteus. E. obtusifolia’s lowest MIC was 0.195 mg/ml from methanol leaf extracts against K. pneumoniae. Activity against C. albican was not as good as against the bacterial strains, as the lowest MIC was 0.78 mg/ml for both species. E. rigida and E. obtusifolia had dose-dependent antioxidant activity, with methanol and ethyl-acetate bark, leaf, and root extracts having the highest activities for both species. This study revealed that in comparison to literature, the activity achieved was similar or better when compared to the likes of E. laevis extracts. The α-glucosidase inhibitory activity reported in this study was dose-dependent. The relationship between antioxidant activity and antidiabetic activity is well documented and this study found that extracts with high antioxidant activity also had similarly high α-glucosidase inhibitory activity. It was E. rigida methanol extracts from bark and roots which exhibited the highest activities compared to E. obtusifolia. However, based on the dosedependent activity, E. obtusifolia is more potent because of the higher activity observed at the lowest concentrations. The study demonstrated that both species have good ethnopharmacological properties and were rich in phytochemicals, particularly phenolics and flavonoids. With E. rigida being the least studied of the two species with only one reported study, it was important to carry out this investigation as it has yielded further evidence that the genus Ehretia has multiple species with medicinal potential.
The effect of organic biostimulants and the mode of application on the growth and biochemical composition of Amaranthus hybridus L.
(2020) Ngoroyemoto, Nelson.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.; Kulkarni, Manoj G.
Abstract available in PDF.
Effect of Rutaceae plant's essential oils and leaf extracts on dermatophytic fungal cell morphology : a hope for the development of an effective antifungal from natural origin.
(2016) Fajinmi, Olufunke Omowumi.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Abstract available in PDF file.
Effects of pruning and fertilizer on growth, phytochemistry and biological activity of Sutherlandia frutescens (L.) R.Br.
(2017) Raselabe, Maanda Benjamin.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.; Abdelgadir, Hafiz Ahmed.; Ndhlala, Ashwell Rungano.
Sutherlandia frutescens (L.) R.Br. (Fabaceae), commonly known as cancer bush, is a herb with a long history of traditional use by a variety of cultures. The plant mainly grows in the dry parts of southern Africa, mostly in the Western and Eastern Cape as well as the neighbouring countries like Lesotho, Botswana and Namibia. Cancer bush is traditionally used for the treatment of external wounds, internally for fevers, stomach problems, cancer, diabetes, influenza, HIV, depression, eye problems, TB, colds and asthma. The plant is famously known for the treatment of Type 2 diabetes, cancer and HIV. However, these claims remain inconclusive. Recent studies have shown S. frutescens to have antidiabetic, anti-HIV, anti-inflammatory, antibacterial, analgesic, anti-stress, anticonvulsant, antiproliferative and antithrombotic activities. Phytochemical investigations of S. frutescens leaves detected the presence of high levels of free amino acids and non-protein amino acids namely: canavanine, gamma aminobutyric acid (GABA) and pinitol. The presence of these compounds has been reported to be responsible for its reputed effectiveness in a wide range of illnesses. In view of its importance as a multipurpose medicinal crop, it is important to bring this plant under cultivation and determine agronomic requirements for its successful cultivation. Several factors can be investigated to enhance the growth and increase the level of active ingredients. The current study was aimed at evaluating the effect of pruning and fertilizer levels on the growth, phytochemistry and biological activity of Sutherlandia frutescens. Seeds were sown in seedling trays to produce seedlings. One-month-old seedlings were then transplanted on a prepared field. The study trial was carried out at the Agricultural Research Council-Vegetable and Ornamental Plants Research Station (ARC-VOP). The experiment was conducted in a randomized complete block design (RCBD) with three pruning levels, three fertilizer levels and four replicates. There were 9 treatments, namely; no pruning (P0), tip-pruning (P1) and heading back (P2) in combination with levels of fertilizers as follows: 200 kg/ha NPK (F1), 100 kg/ha NPK (F2) and 0 kg/ha NPK (F0). Plants without treatments were considered as controls. Growth parameters taken were plant height, stem diameter, chlorophyll and Leaf Area Index (LAI). Dried leaf samples were analysed for the presence of secondary metabolites and antidiabetic activities. There was no significant interaction effect between pruning and fertilizer levels amongst all parameters measured in this study. Pruning treatments had a significant effect on the LAI at week one and week two but did not affect the plant height, stem diameter and chlorophyll content. Different levels of fertilizers had a significant effect on the LAI, where 100 kg/ha NPK significantly increased LAI at week one and week two. In an investigation which was conducted from January to May 2015, plants showed yellowing, stunting, and high levels of infestation expressed as extensive galling on the roots which led to the nematode infestation study. Nematodes were extracted from the roots of a healthy living, a wilted and a dead plant, as well as from the rhizosphere soil. A small population of Scutellonema, Pratylenchus, Helicotylenchus and Tylenchorhynchus were identified. Examination of the root of an infected plant revealed the presence of root-knot nematodes (Meloidogyne javanica) in large numbers. Juveniles, eggs and females were isolated, and the species were identified on the basis of morphological characteristics. Symptoms usually associated with root-knot nematodes were observed on the roots of the wilted plant and the soil in which the plant was growing. Extracts from all nine treatments showed stronger activity against α-glucosidase than the positive control acarbose. The highest α-glucosidase inhibitory activity was demonstrated by the treatment with no pruning (P0) while the heading back (P2) treatment exhibited the lowest inhibitory activity. Fertilizer levels at 200 kg/ha (F1) NPK resulted in a significantly higher α-glucosidase inhibitory activity compared to other fertilizer treatments. The presence of secondary metabolites (including total phenolics and flavonoids) was determined qualitatively. The total phenolic content was determined using the Folin-Ciocalteu method and flavonoids were determined using the vanillin HCL assay. The study showed that pruning and fertilizer increased the production of secondary metabolites in S. frutescens as compared to the control. Fertilizer at 200 kg/ha NPK (F1) did seem to improve phenolics and flavonoids with pruning but phenolic levels were actually quite low when treatment was P0F1. Total phenolics and flavonoids were significantly increased by the heading back (P2) treatment and decreased in the treatment with no pruning (P0). The application of fertilizer at 200 kg/ha NPK (F1) improved the production of secondary metabolites, and reduced production of secondary metabolites was recorded in plants that received no fertilizer. There was no direct correlation between the level of phytochemicals and the antidiabetic activity recorded. This study examined the effects of different levels of pruning and fertilizers on the growth of S. frutescens. The results showed that there was no significant difference. At this stage, no positive recommendations can be made for cultivating S. frutescens. Plant extracts showed good antidiabetic activities in response to different pruning and fertilizer treatments. This was further seen as an increase in the production for secondary metabolites. However, further investigation of plant cultivation practices and further screening for bioactivities is required. S. frutescens may offer a new source of drugs for diabetes mellitus and other related diseases.
Elicitation, metabolomic analysis, and identification of antidiabetic compounds from selected indigenous plants = Ukuvuselelwa, Uhlaziyo Lokugayeka, nokuhlonzwa Kwezingxube Zesinqindasifo Sikashukela Ethathwe Ezihlahleni Zendabuko Eziqokiwe.
(2022) Ogbe, Abdulazeez Adeola.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Diabetes mellitus (DM) is an endocrine disorder associated with high blood glucose levels accompanied by disruptions in the metabolism of fat, proteins and carbohydrates. DM is a chronic, non-communicable and medically incurable disease affecting millions of people globally, resulting in high morbidity and mortality rates, especially with the lingering coronavirus disease of 2019 (Covid-19). The use of western antidiabetic medicine has posed many challenges due to their perceived overall safety, treatment failure and cost. Many African communities rely on medicinal plants and their bioactive compounds as sources of medicine as a consequence of the poor state of health facilities, shortage of medical doctors and unaffordability of treatments. For this reason, this study partly evaluated the phytochemical contents, in vitro antioxidant and hypoglycaemic potentials of eleven indigenous plants using five different solvents. Putative hypoglycaemic agents from one of the most promising and readily available species were also identified using in silico molecular modelling. Secondary metabolites and their pharmacological activity have been reported as the basis for the wide use of plants in traditional medicine. However, due to the indiscriminate harvesting and environmental pressure, many valuable indigenous plant species have gone into extinction or are at least threatened. Moreover, plants' bioactive compounds are often produced in minute quantities, and prevailing environmental conditions further influence their concentrations in plants. Thus, due to indigenous plants' industrial and medicinal value, deliberate cultivation and elicitation strategies have been adopted for the en masse production of uniform indigenous plants and to influence the quality and quantity of their active principles. Thus, this study also assessed the effects of individual and co-inoculation of two isolated drought-resistant and growth promoting endophytes on the growth, drought tolerance, medicinal efficacy and metabolome changes in the leaves of Endostemon obtusifolius. In this research, the eleven plants were selected based on the traditional uses of the plants (or their related available species) for treating various ailments, including DM. The preliminary phytochemical quantification results revealed that the highest concentrations of phenolics, flavonoids and tannins were found in the crude extracts of Combretum krausssii, Lippia javanica, Psidium guajava, Pentanassia prenulloides, E. obtusifolius, Syzgium cordatum, Pachira aquatic and Catha edulis. The inhibitory effects of the crude extracts against the digestive enzymes α-amylase and α-glucosidase also showed that the crude extracts of C. edulis, C. krausssii, L. javanica, P. aquatica, P. guajava, P. prenulloides, E. obtusifolius and S. cordatum displayed excellent in vitro antioxidant and antidiabetic properties. These results validate the extensive use of these plants in the treatment of DM in many African communities. Furthermore, the 80% ethanol (v/v) leaf extract of S. cordatum (one of the most active and readily accessible specie from the previous study) was fractionated into four sub-extracts [petroleum ether (PE), dichloromethane (DCM), ethyl acetate (EtOAc) and water], and their phytochemical content, in vitro antioxidant and antidiabetic capacities were evaluated. Although the EtOAc extract was the richest of the sub-extracts in total phenolics, all four sub-extracts of S. cordatum showed good in vitro free radical scavenging and hypoglycaemic activities. In silico modelling evaluation of some (34) bioactive principles found in the Gas Chromatography-Mass Spectroscopy (GC-MS) analysis of the PE, DCM and EtOAc sub-extracts revealed that 21 compounds including andrographolide, benzylidene-iditol, cubenol and deoxyspergualin and bis[3,3,4,7-tetramethyl-1,3-2H-benzofuran-1-yl]-ether returned binding energy scores ≤ -7.5 kcal/mol against α-amylase and α-glucosidase enzymes indicative of their hypoglycaemic potentials. The physicochemical and toxicological properties of andrographolide, benzylidene-iditol, bis[3,3,4,7-tetramethyl-1,3-2H-benzofuran-1-yl]-ether and cubenol were predicted to be soluble with high gastrointestinal solubility and non-toxic following Lipinski's rule of five and Veber's rule. Thus, these results indicate that these compounds are potential candidates for oral drugs. The drought tolerance and in vitro plant growth-promoting properties of some endophytes isolated from E. obtusifolius (another active antidiabetic plant identified from the previous experiment) was evaluated. A total of 26 culturable endophytes (twelve fungi and fourteen bacteria) were isolated from the organs (leaf and root) of E. obtusifolius. These endophytic species displayed varying in vitro drought stress tolerance and plant-growth-promoting capacities. Two promising drought stress-tolerant and plant-growth-enhancing endophytic species (Fusarium oxysporum and Paenibacillus polymyxa) were subsequently identified using molecular tools. The identified bacterium (P. polymyxa) and fungus (F. oxysporum) exhibited a symbiotic relationship in an in vitro dual culture experiment. Paenibacillus polymyxa and F. oxysporum individual and co-inoculation differential effects on their host under varying water regimes was further evaluated. The plants were raised with or without endophyte infection under three watering regimes for two months, and their therapeutic efficacy, physiological, biochemical and metabolic responses were assessed. In this study, drought stress markedly affected the growth and hypoglycaemic potentials of E. obtusifolius. On the other hand, endophyte inoculation generally enhanced the dry shoot and root biomass, chlorophyll contents and fluorescence, total soluble sugar, relative water content, proline contents and superoxide dismutase activities in the leaves of E. obtusifolius, whereas their electrolyte leakage and malondialdehyde contents were lowered. As for phytochemical accumulation, while the total phenolic contents were slightly enhanced by the inoculation of endophytes in the leaves of E. obtusifolius, the flavonoid contents of the plant increased as the water deficit worsened. The EtOAc crude extracts' free radical scavenging capacity across the treatments remained unchanged; their in vitro α-glucosidase activity was negatively affected under moderate and severe drought stress but improved with endophyte inoculation. The metabolome difference between the twelve treatments was evaluated using GC-MS based metabolomics. The bi-plot PCA result revealed that the metabolome of fungal inoculated moderately stressed E. obtusifolius correlated less with the other E. obtusifolius plants under different treatments. Additionally, a heatmap of eight differential metabolites showed that the most responsive treatment (the co-inoculated severely drought-stressed plants) produced the highest quantities of non-protein amino acids and organic acids known to protect plant cells during abiotic stress. The leaf extracts of S. cordatum and E. obtusifolius showed remarkable antioxidant and antidiabetic potentials in this study. Although the putative active principles of these plants were identified using GC-MS analysis, proper isolation and quantification of these compounds can be explored by future studies. Moreover, some culturable endophytic species were isolated from the E. obtusifolius organs. Paenibacillus polymyxa and F. oxysporum showed their drought stress mitigating capacity in E. obtusifolius under varying water regimes. Although the concentration of some identified antidiabetic compounds in E. obtusifolius were up regulated, the mechanism involved in this observation requires further investigations. IQOQA Isifo sikashukela (Diabetes mellitus - DM) siwukungasebenzi kwezitho zangaphakathi okuhambisana nobuphezulu kwamazinga eglukhosi egazini, kuhambisana nokuphazamiseka kokugayeka kwamafutha, izakhamzimba ezingamaphrotheni nezinikimandla. IDM iyisifo esingelapheki, esingathelelani nesingelapheki ngokwemithi, esiphethe izigidi zabantu emhlabeni jikelele, kuphethe ngamazinga okugula aphezulu nokufa imbala, ikakhulu esimeni sokungakhawuki kwesifo ukhuvethe (coronavirus disease of 2019 - Covid-19). Ukusetshenziswa kwemithi eyizinqindimandla zesifo sikashukela yasentshonalanga sekudale izinselelo eziningi ngenxa yokucabangeka ukuthi kuthinta ukuphepha kwayo jikelele, ukwehluleka ukwelapha nezindleko. Iningi lemiphakathi yase-Afrika yethembele ezihlahleni eziyimithi (yokwelapha) nezingxube zayo ezinokuphilayo njengesizinda semithi ngokomphumela wesimo esingenele sezinsiza zezempilo, ukwesweleka kodokotela abelaphayo nokungameleki kwezindleko zokwelashwa. Ngalesi sizathu-ke, ingxenye yalolu cwaningo yahlola okuqukethwe ngamakhemikhali ezihlahla, ngezivikelizinhlayiya ezifakwe eshubhini lokuhlola nama-ejenti anezinga eliphezulu likashukela egazini avela kolunye uhlobo olwethembisayo nolutholakala kalula olwatholwa kusetshenziswa ukumodela kwemolekhula ngekhompiyutha. Kwabikwa ukuthi ukugayeka kokudla kwezinga lesibili, nomnyakazo wakho wezokwelapha ngemithi kuyisisekelo sokusetshenziswa kabanzi kwezihlahla emithini yendabuko. Nokho-ke, ngenxa yokuvunwa okunga okungakhethi nengcindezi yezokuvikelwa kwezemvelo, iningi lezinhlobo zezihlahla zendabuko zenani eliphezulu seziphelile kungenjalo-ke zisengcupheni. Naphezu-ke, izingxube ezinokuphilayo zivama ukukhiqizwa ngezamba ezincanyana, nezimo zokuvikelwa kwezemvelo ezikhona ziphinda zibe nomthelela wazo ogxile ezihlahleni. Ngakho-ke, ngenxa yenani lezihlahla zendabuko ngokwezimboni nakwezokwelapha, sekufakwe ngokwenhloso amasu okuzitshala nokuzivuselela ukuze zikhiqizele ngobuningi bazo nangokwefana kwezihlahla zendabuko nokuba nomthelela kohlonze nasebuningini kwemithetho esebenzayo. Ngalokho-ke lolu cwaningo lwahlola imithelela yokunye nokugonywa okuhlanganisiwe kokukhethiwe kokuhlala ezinhlayiyeni eziphilayo zokukhula, okumelana nesomiso nokukuthaza ukukhula, ukumelana nesomiso, ukwenza kahle ekwelapheni nezinguquko zokugayeka emaqabungeni e-Endostemon obtusifolius. Naphezu-ke, kwahlolwa i-ethanol (v/v) emuncwe emaqabungeni engama-80%, ye- S. cordatum (engenye yezinhlobo ezitholakala kalula nesebenzayo esukela ocwaningweni lwaphambilini) yacozululwa yaba ngokumunciwe okuncanyana [petroleum ether (PE), dichloromethane (DCM), ethyl acetate (EtOAc) namanzi], nokwamakhemikhali ezihlahla kwawo, nezivikelizinhlayiya ezifakwe eshubhini lokuhlola, nokukwazi ukulwa nesifo sikashukela. Nakuba isimuncwa i-EtOAc kwakuyiyo ecebe kunazo zonke izimuncwa ezincane zamafenolikhi aphelele, zonke izimucwa ezincane zozine ze- S. cordatum zakhombisa ukukwazi ukuthungatha okukhululekile nokunamandla nokulwa nezinga eliphezulu likashukela egazini. Ukuhlolwa kokumodelwa ngokwekhompiyutha, kwalokho okunokuphilayo okungama (34) ngokwemitheshwana yokunokuphilayo okwatholwa ohlaziyweni lwe-Gas Chromatography-Mass Spectroscopy (GC-MS) kwezimuncwa ezincane ze- PE, DCM ne-EtOAc zakhombisa ukuthi izingxube ezingama-21 kubalwa kuzo ne- andrographolide, benzylidene-iditol, cubenol ne-deoxyspergualin nebis[3,3,4,7-tetramethyl-1,3-2H-benzofuran-1-yl]-ether kwabuyisa imiphumela yamandla okubophezela ≤ -7.5 kcal/mol aphikisana nama-enzayimu e-α-amylase ne-a-glucosidase akhombisa ukuthi angakwazi ukulwa nezinga eliphezulu lesifo sikashukela. Okuqukethwe yiphysicochemical netoxicological andrographolide, benzylidene-iditol, bis[3,3,4,7-tetramethyl-1,3-2H-benzofuran-1-yl]-ether necubenol kwabikezelwa ngokukwazi ukugayeka ngokomgudusisu-mathumbu wokugayeka nokungabi nasihlungu kulandela umthetho kaLipinski wokuhlanu nomthetho weVeber. Ngalokho-ke, le miphumela ikhombisa ukuthi lezi zingxube zinganethuba lokungenela ukuba yimithi ephuzwayo. Kwahlolwa ukukwazi ukumela isomiso nokukwazi ukukhuthaza ukukhuliswa kwezinhlaka zezihlahla eshubhini lokho okuhlala kwezinye izinhlayiya zokuphilayo okwakhishwa ku- E. obtusifolius (esinye sezihlahla esilwa nesifo sikashukela esahlonzwa elingeni laphambilini). Isamba salokho okuhlala ezinhlayiyeni zokuphilayo sokukhulisekayo okungama-26 (ishuminambili lesikhunta namagciwane ayishumi nane) kwehluswa ezithweni (amaqabunga nezimpande) ze- E. obtusifolius. Lezi zinhlobo ezinokuhlala ezinhlayiyeni zalokho okuphilayo zakhombisa ukumelana nesomiso okwahlukene uma zifakwa eshubhini lokuhlola nokukwazi ukuba ngokukhuthazwa kokukhula kwezihlahla. Kwagcina sekutholwe izihlahla ezimbili ezikwazi ukumelana nokuhlukunyezwa yisomiso nokukwazi ukukhuthaza ukukhuliswa kwezihlahla kohlobo okuhlala kulo okuphilayo (Fusarium oxysporum nePaenibacillus polymyxa) kusetshenziswa amathuluzi anobumokhula. Ubugciwane obatholakala (P. polymyxa) nobukhunta (F. oxysporum) bakhombisa ubudlelwano obunokwencikana elingeni leshubhu lokuhlola elikhulisa ngakubili. Kwaphinda kwahlolwa iPaenibacillus polymyxa ne-F. oxysporum okungakunye nomgomo ohambisana nemithelela ehlusayo kokungumgcini wakho ezinhlotsheni zamanzi ezahlukene. Kwahlolwa izihlahla ezakhuliswa ngaphandle kokufakwa okuhlala kokuphilayo, ngaphansi kwezinhlobo ezintathu zokuchelela ngezinyanga ezimbili, nokusebenza kahle kokukwazi ukwelapha kwazo, ngokomzimba, ngokwamakhemikhali aphilayo nokwenza kwakho ekugayweni kokudla. Kulolu cwaningo, ukuhlukumeza kwesomiso kwaba nomthelela omkhulu ekukhuleni nokukwazi ukuvimba izinga eliphezulu likashukela kwe- E. obtusifolius. Ngakolunye uhlangothi, ukugonywa kwalokho okuhlala kokuphilayo kwavama ukukhuthaza ibhayomasi yezithombo nezimpande, okuqukethwe yiklorofili nokukhanyayo, ushukela oncibilika ngokuphelele, isikalo samanzi esinokuhambisana, okuqukethwe ngokwenziwa yiproline nesuperoxide okwenzeka ekuhlakazekeni kabili emaqabungeni e-E. obtusifolius, kanti kwehliswa ukuvuza kwe-elekthrolaythi yakho nokuqukethwe yimalondialdehyde. Ngokokunqwabelana kwamakhemikhali ezihlahla, ngenkathi okuqukethwe kwefenolikkhi kwakukhuthazwa ngukugonywa kwalokho okuhlala kokuphilayo emaqabungeni e-E. obtusifolius, okuqukethwe yiflavanoydi kwesihlahla kwakhula ngenkathi ukuncipha kwamanzi kudlanga. Okwe-EtOAc okungagayiwe okumuncwe ngomthamo okhululekile nokokuzingela okumawala kuzo zonke izinhlobo zokwelapha kwahlala kungaguqukile; ukusebenza kwe- α-glucosidase eshubhini lokuhlola kwatheleleka kabi ngaphansi kokuhlukunyezwa yisomiso esiphakathi nendawo nesadlulele, kodwa kwathuthuka ngokugonywa ngokuhlala kokuphilayo. Umehluko ekugayweni phakathi kokwelaphayo okuyishumi nambili wahlolwa kusetshenziswa i- GC-MS egxile kwezokugaya. Umphumela we bi-plot PCA waveza ukuthi ukugayeka kwesikhutha esigonyiwe kwahlukumeza ngokuphakathi kwendawo i- E. obtusifolius ehambisana kancane nezinye izihlahla ze- E. obtusifolius ngaphansi kokwelashwa okwahlukile. Ngokwengeziwe-ke, ibalazwe lokushisa kokugaya okunomehluko okuyisishiyagalombili kwakhombisa ukuthi ukwelapha okuzwela kakhulu (kwezihlahla ezigonywe ngokuhambisana ezihlukunyezwe kakhulu yisomiso) kwakhiqiza izibalo eziphezulu zezakhimaphrotheyni nama-esidi emvelo aziwa ngokuvikela izinhlayiya zezihlahla ngenkathi yokuhlukunyezwa ngokungenampilo. Okumuncwe emaqabungeni e- cordatum ne-E. obtusifolius kwakhombisa ubukhona kwezivikelizihlahla nokulwa nesifo sikashukela kulolu cwaningo. Nakuba imitheshwana esebenzayo ehlawumbiselwayo kwalezi zihlahla yabukwa kusetshenziswa uhlaziyo iGC-MS, ukwahluswa okufanele nokubalwa kwalezi zingxube kungahlolwa ezifundweni zangomuso. Naphezu-ke ezinye izinhlobo ezikhulisekayo zalokho okuhlala kokuphilayo zehluswa ezingxenyeni ze-E. obtusifolius. IPaenibacillus polymyxa ne-F. oxysporum kwakhombisa ukukwazi ukunciphisa ukukhandlwa yisomiso kwe- in E. obtusifolius okwalawulwa ngokuphakama, ukusebenza okwafakwa ekwethameleni kudinga okunye ukuhlolwa.
Enhancing phenolic compound production in medicinal plants.
(2017) Paine, Christine Susan.; Finnie, Jeffrey Franklin.; Van Staden, Johannes.
Abstract available in PDF file.
Ethnobotanical study of plants from Pondoland used against diarrhoea.
(2012) Madikizela, Balungile.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Diarrhoea and related diseases are the most common causes of death in children, especially from developing countries, killing about 1.5 million children under the age of five yearly. In South Africa, diarrhoea is the third leading cause of death. This condition results from food and water sources infected with Campylobacter spp., Escherichia coli, Salmonella spp., Shigella spp., Giardia intestinalis and Cryptospondium parvum amongst others. Diarrhoea spreads through faeces-contaminated water. Hence, infection is more common when there is a short supply of clean drinking and cooking water. Waterborne diseases are common in rural communities of Bizana because the majority of rural dwellers depend largely on water from unprotected sources. Most of the pathogens that cause diarrhoea have developed resistance to several antibiotics. Therefore there is a need for new and safe antidiarrhoeal drugs. Most people in developing countries use traditional medicine to treat all kinds of diseases including diarrhoea and South Africa is no exception. Each cultural group in South Africa has different medical solutions for the prevention and curing of the same disease. The people from Pondoland (AmaMpondo), around Bizana have a strong tradition of using medicinal plants for the cure and prevention of several conditions including diarrhoea. Although several researchers have conducted different types of studies in many parts of South Africa to evaluate the efficacy of traditional medicine used in the treatment of diarrhoea, there is, however, still a lot of undisclosed data that should be collected. The aims of this research were to record and collect medicinal plants that are used for treating diarrhoea in Bizana, Pondoland in the Eastern Cape and evaluate them for their pharmacological properties. An ethnobotanical approach is one of several methods that have been useful in selecting plants for pharmacological research, yielding better results than other plant selection methods. Using questionnaires, this approach was used to record plants that are used for treating diarrhoea in Bizana for testing in pharmacological assays. From the completed questionnaires, nine plants were selected for bioassays based on their higher frequency index, and the fact that the plants have never been evaluated against diarrhoea causing-microorganisms. The study revealed 34 plant species belonging to 21 families as being used in treatment of diarrhoea in the study area. Psidium guajava was the most mentioned plant species. The dried, ground plant materials were each extracted non-sequentially using petroleum ether (PE), dichloromethane (DCM), 70% ethanol (EtOH) and water. Among all the extracts, 70% ethanol yielded the highest quantity of crude extract. The extracts were each evaluated for their antibacterial, anti-inflammatory and genotoxicity properties. For the antibacterial activity, the following diarrhoea causing microorganisms were used: Gram-positive Staphylococcus aureus and Gram-negative Campylobacter jejuni, E. coli and Shigella flexneri. A microdilution assay (for S. aureus, E. coli and S. flexneri) and the disk diffusion technique (for C. jejuni) were used for antibacterial testing. The extracts were also evaluated for their ability to inhibit cyclooxygenase (COX-1 and -2) enzymes. Genotoxicity was evaluated using the Salmonella microsome assay without S9 metabolic activation. Three strains of Salmonella typhimurium TA98, TA1535 and TA1537 were used. The evaluated plant extracts showed a broad spectrum of inhibitory activity with MIC values ranging from 0.098-12.5 mg/ml and mean zone inhibition percentage ranging from 0-73%. The best activity was exhibited by DCM extracts of Rapanea melanophloeos, EtOH extracts of Ficus craterostoma and Maesa lanceolata with MIC values of 0.098 mg/ml and EtOH extracts of Searsia chirindensis with 73% mean zone inhibition percentage. The inhibitory activity against COX-1 enzyme was higher than COX-2, with 19 plant extracts for the former and 7 for the latter. The highest inhibition of COX-1 was shown by EtOH extracts of F. craterostoma and the DCM extract of S. chirindensis at 100%. Highest percentage COX-2 inhibition was shown by water extracts of F. craterostoma and DCM extracts of Tecoma capensis with 99.5% and 99.0% respectively. None of the tested plant extracts were mutagenic, at all concentrations tested against all tester strains of the bacteria. The results of this study demonstrate that people still have a rich and diverse pool of knowledge concerning the uses of plants against diarrhoea. The data also show that plants form part of the cultural heritage of the communities in Pondoland. Therefore it is important to urgently save the people’s cultural heritage by recording the existing knowledge and confirming therapeutic uses of plants through scientific methods. This will prevent the information from vanishing together with the ageing knowledge holders. In light of the fact that the evaluated plants were selected based on their ethnobotanical use for treating diarrhoea, the activities reported here goes a long way in adding value to the plants used as part of traditional medicine.
Ethnopharmacological study on plants used for skincare and beauty by some Xhosa communities.
(2018) Thibane, Vuyisile Samuel.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
The paraphrase “beauty lies in the eyes of the beholder” by Plato, a Greek philosopher, has echoed through the fabrics of time and still echoes in our generation. The statement simply ought to refer to that the observer gets to decide what is “beautiful” in their eyes. The decision on what and who is beautiful is heavily influenced by one’s surroundings. In a digital-market environment the concept of beauty enhancement is paraded by bigger forces to drive their own agenda. The desire to enhance one’s facial appearance has significantly contributed to the observed growth of the beauty industry. The notable growth of the industry has in some cases resulted in unpleasant consequences due to the side effects of some of the products in the market. In this global-blooming industry products are traded and exchanged at a rapid rate. Introduction of safer natural beauty enhancement products are required for the South African market if we were to alleviate those with undesirable side effects and could combat some socio-economic challenges through job creation. The use of plants as the source of natural compounds has proven to be a reliable strategy in ethnopharmacological applications. The Eastern Cape Province has a rich plant biodiversity and the communities have immense indigenous knowledge (IK) on the use of these plants. There is a need to explore the pharmacological application of these plants by introducing beauty enhancement product formulations made from local resources. The project was aimed at documenting and conductingethnopharmacological evaluation of plants used for skincare and beauty for their potential in formulation of beauty enhancement products. An ethnobotanical survey was conducted to document plants that are used by communities in the Raymond Mhlaba municipality for skincare and beauty. Knowledge holders were identified by purpose sampling method and the interviews were conducted in isiXhosa using a structured questionnaire. Information on demographics, names of the plant, type of plant, plant part used, method of preparation and administration and frequency of use was collected and captured in the questionnaires. The Asphodelaceae and Asteraceae were the most represented families of the plants used for skincare and beauty. The communities used sustainable harvesting practices as the leaves were the most utilized plant parts. The most reported beauty enhancement uses were for achieving desired skin complexion and for skin smoothness, with both accounting up to 50% of the reported plant usages. Sixteen plants with the highest frequency index (FI) were selected from the ethnobotanical survey for ethnopharmacological studies related to beauty enhancement. This included Acokanthera oblongifolia (Hochst.) Codd, Aloe ferox Mill, Arctotis arctotoides (L.f) O.Hoffm, Bulbine frutescens (L.) Willd, Cassipourea flanaganii (Schinz) Alston, Chenopodium album L, Clausena anisata (Willd.) Hook.f ex Benth, Haemanthus albiflos Jacq, Marrubium vulgare L, Ilex mitis (L.) Radlk, Plantago lanceolata L, Rorippa nasturtium-aquaticum (L.) Hayek, Sonchus asper L, Symphytum officinale L, Ruta graveolens L and Urtica urens L. The antimicrobial activity of plant extracts was assessed using the microdilution bioassay to determine the minimum inhibitory concentrations (MIC). The antimicrobial activity of petroleum ether (PE), dichloromethane (DCM), 70% aqueous ethanol (v/v) and water extracts of the selected plants were assessed against infectious skin microorganisms including Bacillus subtilis ATCC 6051, Brevibacillus agric ATCC 51663, Staphylococcus aureus ATCC 12600, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 11775, Klebsiella pneumoniae ATCC 13883, Candida albicans ATCC 10231 and the dermatophytes Microsporum canis ATCC 36299, Trichophyton mentagrophytes ATCC 9533 and Trichophyton tonsurans ATCC 28942. The majority of the tested plant extracts were effective and inhibited the skin commensal bacteria E. coli with MIC values less than 100 μg/mL. Prolonged infections by commensal bacteria can condition the skin environment and provide favourable conditions for more opportunistic bacteria such as the Staphylococci genus. Ethanol extracts of C. flanaganii and U. urens expressed high antibacterial activity against S. aureus with MIC values less than 100 μg/mL. Ethanol extracts of R. graveolens and dichloromethane extracts of A. arctotoides were effective at inhibiting S. epidermidis and S. aureus, respectively. Inhibition of two opportunistic bacteria has a positive effect on skin tone, due to the scarring and darkening associated with infection by the Staphylococci genus. There was notable activity recorded against C. albicans and dermatophytes M. canis, T. mentagrophytes and T. tonsurans by extracts of A. oblongifolia, A. arctotoides, C. flanaganii, I. mitis and R. graveolens at different polarities with MIC’s less than 1000 μg/mL. The phenolic content and antioxidant activity of the plants were determined by assessing 50% aqueous methanol extracts (v/v) for their total phenolic and flavonoid content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and the coupled oxidation of linoleic acid and bleaching of β-carotene. The antioxidant mechanism of phenolic compounds associated with beauty enhancement has been proposed to be due to their free radical chain breaking capabilities, metal chelation, oxidant quenching and inhibition of enzymatic activity. The total phenolic content of A. ferox, I. mitis and C. flanaganii were significantly high with recorded values ranging from 37.87 to 50.34 mgGAE/g. The flavonoid content of C. flanaganii, A. oblongifolia and P. lanceolata were significantly high. Methanol extracts of R. graveolens and C. flanaganii expressed the highest antioxidant activity, with IC50 values comparable to the standard antioxidant when assessed for their DPPH radical scavenging activity. The presence of antioxidants in the skin structural layers has a positive effect on the health and function of the skin. Extracts of U. urens, A. ferox, C. flanaganii, B. frutescens, P. lanceolata, H. albiflos, M. vulgare, C. anisata, S. officinale and R. nasturtium-aquaticum expressed good metal chelating potential. The highest oxidative protection in the β-carotene linoleic acid model with comparative oxidation rate ratio (ORR) to the positive control was observed for C. flanaganii, S. officinale and U. urens. The results indicate the ability of the plant extracts to provide protection against increased levels of lipid peroxidation in the skin, an important factor in beauty enhancement, due to delaying the age process. The photo-protective effect of the plant extracts was measured by calculating the sun protection factor (SPF). The SPF is the ratio of ultraviolet (UV) radiation required to produce minimal erythema dose (MED) in protected skin to unprotected skin with higher values indicative of increased protection from photo damage. Ethanol extracts of P. lanceolata, C. flanaganii, A. oblongifolia, I. mitis and A. arctotoides exhibited SPF values of more than 15, which translated to photo protection of the skin against UVB radiation by more than 93.3%. The plant extracts demonstrated the highest absorbance of UVB radiation at a wavelength region between 300 – 305 nm. These will protect the skin against UV-induced oxidative damage and enhance the skin’s health and function. The inhibition of enzymes with beauty enhancement potential by the plant extracts was assessed against tyrosinase, secretory phospholipase A2 (sPLA2), lipoxygenase (15-LOX) and cyclooxygenase (COX-1 and COX-2). Ethanol extracts of R. nasturtium-aquaticum, C. anisata, S. officinale and C. flanaganii expressed good anti-tyrosinase activity. The coupled protection against UV-induced damage and modulation of the tyrosinase enzyme activity can be exploited to achieve the desired skin complexion. The anti-inflammatory studies revealed the potential of extracts of C. flanaganii, P. lanceolata and R. nasturtium-aquaticum to serve as dual inhibitors of 15-LOX and COX-2 enzymes. The inhibition of 15-LOX and COX-2 is effective at resolving psoriasis, a skin-inflammatory associated disease which has a negative effect on the health and beauty of the skin. The effectiveness of ethanol extracts of C. flanaganii, C. album, C. anisata and R. nasturtium-aquaticum in maintaining the cells health and function was examined on human epidermal melanocytes (HEM) cell lines. Ethanol extracts of C. flanaganii, C. album, C. anisata and R. nasturtium-aquaticum were able to inhibit cellular tyrosinase activity and therefore reduce melanin production. The effective concentrations of the extracts were further reported as non-toxic to melanocytes. The observed anti-tyrosinase activity of the extracts against HEM cell lines contribute positively in achieving the desired skin complexion while providing photo protection against UV-induced damage. Therefore, plant extracts that are efficient and safe to use can be incorporated into formulations intended for beauty enhancement and further analysed under clinical trials. The study further suggests that the model undertaken be promoted to individuals and corporations interested in formulation of cosmeceuticals to ensure the safety and efficiency of their products.
Evaluation of plants used in African traditional medicine for asthma and related conditions.
(2014) Motlhatlego, Katlego Ellena.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Traditional medicine is a form of discipline that has been applied within most South African societies with the objective of enhancing the physical and psychological health system in the country. Asthma is a complex inflammatory disease that involves the narrowing of the airways. The prevalence of asthma is increasing worldwide, and this chronic disease has been identified as a significant cause of morbidity and mortality. Asthma poses a major threat to health across the population of South Africa. The adverse effects of current treatments have encouraged the use of traditional medicine. The primary aim of the research study was to evaluate the efficacy of plants used in African traditional medicine against asthma and chest infections. This was achieved by screening Adansonia digitata, Ballota africana, Catha edulis, Datura stramonium, Pelargonium sidoides, Siphonochilus aethiopicus, Xerophyta retinervis and Zantedeschia aethiopica for their pharmacological properties against key bacteria; Staphylococcus aureus (ATCC 12600), Klebsiella pneumonia (ATCC 13883), Streptococcus pyogenes (ATCC 12344) and Haemophilus parainfluenzae (ATCC 7901) as well as the fungus Candida albicans (ATCC 10231) these microorganisms are known to cause chest infections. In the microdilution antibacterial assay, the crude extracts of the screened medicinal plants showed activity at minimal inhibitory concentrations (MICs) ranging from 0.098 to >12.5 mg/ml. In the disc-diffusion assay, only the ethanol extract of stems from Siphonochilus aethiopicus and water extract of leaves from Zantedeschia aethiopica showed zones of inhibition of 13.24 and 21.10 mm. All the other screened extracts showed no zones of inhibition, which may possibly indicate that plants were ineffective against Haemophilus parainfluenzae. One or more extracts from the tested plants were effective against one or both Gram-positive bacteria investigated in the study. There was no good antifungal activity shown in the study as the MIC and minimal fungicidal concentrations (MFCs) values were higher than 1 mg/ml. Genotoxicity of medicinal plant extracts that showed good antibacterial activity ≤ 0.5 mg/ml was evaluated using the Salmonella microsome assay without S9 metabolic activation. Two strains of Salmonella TA98 and TA102 were used in the Ames test. Most tested extracts were non-mutagenic in the Ames test except for the Siphonochilus aethiopicus roots which showed a dose dependent increase. The ethanolic crude extracts were screened in an immunological assay to determine the level of competitive binding to the receptors for the treatment of asthma and related conditions. Histamine is intimately associated with allergies. Datura stramonium flowers and fruits experienced remarkable histamine binding of approximately 97% at both concentrations (400 and 800 μg/ml). The immunological activity may be attributed to the various phytochemical constituents in the crude extracts. Ballota africana leaves and stems, Datura stramonium flowers and fruits, roots and stems as well as Zantedeschia aethiopica leaves showed excellent affinity with histamine ranging between 88 and 97% and these medicinal plants could potentially serve as a new effective antihistamine when compared to the currently available pharmaceuticals. Most of the medicinal plants tested may potentially provide remedies for asthma and related conditions such as eczema, rhinitis (hayfever), anaphylaxis, sinusitis, chronic obstructive pulmonary disease (COPD), emphysema, bronchiectasis and bronchitis.
Flower abscission in potted Plectranthus.
(2013) Rice, Laura Jane.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.; Ascough, Glendon D.
Transport and post-harvest handling of flowers both cut and potted is one of the greatest challenges in the horticulture industry (REDMAN et al., 2002). Ethylene-induced flower abscission is responsible for the loss of crops (KIM et al., 2007). Flower abscission is greater when plants are transported (ABEBIE et al., 2005). This limits the sale of flowers and potted plants to areas close to the site of production and prevents export opportunities. South Africa is home to many spectacular species with great horticultural potential (RICE et al., 2011). Unfortunately however, development of a number of these species for export is difficult due to transport-induced flower abscission. Transport-induced flower abscission is a problem experienced by Dr Gert Brits, a breeder of Plectranthus in Stellenbosch in South Africa. In this study a number of Dr Brits’s Plectranthus varieties were used as model plants to understand the process of transport-induced flower abscission and develop a protocol for the prevention of such abscission. Flow cytometry was used to determine the ploidy levels of each of the varieties. It was important to be aware of this during the experiments as varieties with different ploidy levels have been reported to behave differently under stressful environmental conditions. Of the eight varieties examined, three were diploid (2n), one was triploid (3n), three were tetraploid (4n) and one was a mixopliod (2n/4n) variety. To determine the effects of packaging plants during transport and the effects of darkness on flower abscission, plants were packaged into perspex chambers and kept either in a 16 h photoperiod or in darkness for 96 h. Every 24 h the number of open and unopened flowers that had abscised was recorded. Both packaging and darkness increased flower abscission of open and unopened flowers in all eight varieties. Four varieties preferentially abscised open flowers; while the remaining four preferentially abscised unopened flowers. All eight varieties were exposed to different concentrations of ethylene (0, 0.1, 0.25 0.5, 1 and 2 μll-1) to determine their level of ethylene sensitivity. All of the Plectranthus varieties were determined to be extremely sensitive to ethylene. With 100% flower abscission occurring within 24 h at 1 and 2 μll-1 in all varieties. In order to determine what internal changes were causing this increase in flower abscission under these conditions, the changes in the expression of key ethylene biosynthetic enzymes, cytokinin content and carbohydrates in the flowers were examined. ACS and ACO are the two key enzymes in the ethylene biosynthetic pathway (JOHNSON & ECKER, 1998). Changes in the levels of mRNAs coding for these two enzymes were examined when plants were packaged and put into the dark. In general there was an upregulation of the ethylene biosynthetic pathway and in turn this may have increased ethylene production by the plants under simulated transport conditions. However, the changes were not large enough to be solely responsible for the increased flower abscission observed under simulated transport conditions. The concentrations of 43 cytokinins were measured in pedicle tissue from plants which had been kept in the dark for 0, 24, 48, 72 and 96 h. Of the 43 cytokinins measured 21 were below the level of detection. Concentrations for the remaining 22 cytokinins at each of the time points were examined and it was found that in general cytokinin concentrations increase when plants are packaged and put into the dark. DHZ-type cytokinins remained stable during the 96 h continuous dark monitoring period, with most of the changes observed in the tZ and iP types. Peaks in cytokinin concentrations are often followed by an increase in flower abscission, indicating that an increase in cytokinin concentrations may be one of the factors causing the increase in transport-induced flower abscission. Only glucose and fructose were detected in peduncle tissue. Changes in glucose and fructose over 24 h in the greenhouse and over 0, 24, 48, 72 and 96 h in simulated transport conditions were measured. During the day, glucose and fructose levels increased towards the afternoon and evening and decreased in the early morning. This is consistent with studies conducted on other species (ALONI et al., 1996). When plants were put into the dark, glucose and fructose levels increased slightly at 24 h and then decreased to levels similar to those measured in control plants. Although there were changes in glucose and fructose level in simulated transport conditions, they were very slight and it is unlikely that these changes are not responsible for the transport-induced flower abscission. These results suggest that the observed transport-induced flower abscission is the result of increased cytokinin concentrations and expression of ACO and ACS genes when plants are packaged and put into the dark. These changes in turn cause an increase in ethylene production by the plants, and the build-up of ethylene in the transport container causes flowers to abscise. Ethylene perception by the plant is the step which could be targeted to prevent flower abscission. A number of ethylene antagonists block the ethylene receptors in the plant and in so doing prevent the receptors from binding ethylene and transducing the abscission signal. 1-MCP isone such ethylene antagonist. To test whether 1-MCP could be used for the prevention of flower abscission in Plectranthus, plants were placed in sealed perspex chambers in the light and in the dark and treated with 100 nll-1 1-MCP for a single 6 h treatment, or for 6 h every day prior to continuous exposure to ethylene. 1-MCP treatment greatly reduced ethylene- and transport-induced flower abscission when plants were treated continuously, but reduced flower abscission for the first 24 h when pre-treated with a single 6 h exposure to 1-MCP.Transport-induced flower abscission in Plectranthus is the result of exposure to ethylene. The increase in ethylene production by the plants in transport conditions is likely due to an upregulation of the ethylene biosynthetic pathway and an increase in cytokinin concentrations or movement in the pedicle tissue. This transport-induced flower abscission can be prevented by continuous treatment with 100 nll-1 1-MCP during the transport period. By using 1-MCP plants can be transported for up to 4 d and the opportunity for export is made possible.
Heavy metals in South African medicinal plants with refence to safety, efficacy and quality.
(2014) Okem, Ambrose.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.; Stirk, Wendy Ann.; Southway, Colin.; Street, Renée Anne.
The trend in commercialization of medicinal plant products reflects the excessive exploitation of medicinal plants from the wild populations. Due to widespread soil pollution, there is a likelihood that medicinal plants could be harvested from heavy metal-contaminated soils and thus pose a potential health threat to consumers. Unregulated procurement coupled with the unhygienic trading environment, poor post-harvest handling and processing, represent major routes of heavy metal contamination in medicinal plant products. A comparative screening was carried out to assess the levels of heavy metal contamination in some frequently used South African medicinal plants obtained from out-door traditional medicinal markets and muthi shops. Plant samples were digested using a microwave-assisted acid digestion system and the elemental content determined using inductively coupled plasma optical emission spectrophotometry (ICP-OES). There was multi-elemental contamination in the investigated medicinal plants with elevated levels of Fe, Al and Mn detected in most of the samples and levels of As and Hg were above the World Health Organization limits of 1 mg kg-1 and 2 μg kg-1 respectively. The high levels of metal contaminations in some of the investigated medicinal plants is a health concern and urgent measures are needed to protect the health of consumers. Samples were quantified for their total phenolic and flavonoid contents as well as screened for antibacterial activity. Variable phenolic and flavonoid composition and antibacterial activity showed that the quality and efficacy of medicinal plants sold at traditional medicine markets is compromised. Data obtained from elemental analysis was subjected to hierarchical cluster analysis which categorized samples into four main groups with samples within a group having relatively similar metal analyte compositions. Hierarchical cluster analysis proved to be a valuable tool in this preliminary screening of heavy metal contamination in medicinal plants and can potentially be used to develop a large database for easy monitoring of plant species with hyperaccumulative potentials. Information such as site of collection, plant species and plant part could be a valuable approach to ensure safety, efficacy and quality of medicinal plants sold at traditional medicine markets. Exposure to Cd and Al for six weeks in a pot trial induced responses in Bulbine natalensis, Drimia elata and Hypoxis hemerocallidea and these included variations in heavy metal uptake, growth parameters and physiological changes. Generally, application of Cd and Al at low concentrations (2 and 500 mg L-1 respectively) enhanced growth parameters in the three plant species compared to the control plants. However, at the highest concentrations of Cd 10 and Al 1500 mg L-1 respectively, there was significant growth inhibition. Hypoxis hemerocallidea exhibited good tolerance to Al exposure up to 1000 mg L-1 compared to the other plant species. Some of the physiological changes such as accumulation of free-proline increased progressively with increasing heavy metal treatments in all the investigated plant species. The combined treatment of Cd 5:Al 1000 mg L-1 exhibited synergistic effects on the uptake and accumulation of Cd and Al with values of about 83 and 918 mg kg-1 respectively in the bulbs of D. elata. In B. natalensis, the combined treatment of Cd 10:Al 1500 mg L-1 resulted in the highest amount of Cd (67 mg kg-1) in the bulb samples while the highest amount of Al (1607 mg kg-1) was recorded after treatment with Cd 5:Al 1000 mg L-1. There was an antagonistic effect on the uptake and accumulation of Cd in H. hemerocallidea in the combined treatments. Energy dispersive X-ray analysis of the abaxial leaf surface indicated that more Al was translocated to the shoot in H. hemerocallidea compared to Cd. The bulbs and corms of the investigated medicinal plants are the most extensively utilized plant parts in traditional medicine. High levels of Cd and Al in the bulbs and corms raise public health concerns. Analysis of photosynthetic pigments showed total chlorophyll progressively decrease with increasing heavy metal stress in all three plant species. The effect of Cd and Al on chlorophyll fluorescence in H. hemerocallidea was investigated. Non-photochemical quenching (NPQ) was adversely affected in most of the heavy metal-treated plants indicating a photoinactivation of photosystem II (PSII) reaction centres. In the present study, increasing heavy metal treatment resulted in the inability of H. hemerocallidea to utilize the absorbed light energy leading to oxidative stress. Exposure to Cd and Al treatments for six weeks induced several ultrastructural changes in H. hemerocallidea including damage to the cortical cells and an increase in xylem size. Transmission electron microscopy revealed a complete breakdown of the thylakoids at the highest Cd treatment and the application of Al at moderate and the highest treatment significantly reduced the size of the chloroplasts. These ultrastructural changes could possibly explain the reduced chlorophyll fluorescence and the amounts of total chlorophyll recorded at the higher levels of heavy metal treatments. Biosynthesis and accumulation of secondary metabolites under heavy metal stress were variable in the investigated plants. The moderate Cd treatment at Cd 5 mg L-1 up-regulated the synthesis of total phenolics slightly compared to the controls in B. natalensis. All the other heavy metal treatments down-regulated the synthesis of total phenolics and flavonoids compared to the control plants in B. natalensis. Application of Cd and Al at the lowest concentrations, 2 and 500 mg L-1 respectively up-regulated the synthesis and accumulation of both phenolics and flavonoids in D. elata compared to the control plants. In H. hemerocallidea, the highest amounts of total phenolics and flavonoids were recorded at the moderate Cd treatment (5 mg L-1). High performance liquid chromatography showed a significant decrease in the levels of hypoxoside, a bioactive compound in H. hemerocallidea after heavy metal exposure. The lowest amount of hypoxoside was recorded at the highest concentration of the combined treatment (Cd 10:Al 1500 mg L-1). These variable responses to heavy metal stress indicated the need for in-depth research on changes of secondary metabolites in medicinal plants exposed to heavy metals in order to ensure ultimate quality and efficacy of medicinal plant products. There was a progressive decrease in antioxidant activity as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging in the bulb extracts of B. natalensis and D. elata. The lowest treatment of Al (500 mg L-1) had slightly higher DPPH activity compared to the positive control (ascorbic acid). Extracts of H. hemerocallidea exhibited a progressive increase in DPPH activity with increasing heavy metal treatments. There was a significant decrease in the DPPH activity at the highest Cd application (10 mg L-1) compared to the control plants indicating a loss in the biosynthesis of important bioactive compounds at high levels of heavy metal exposure. Cadmium applied at low and moderate concentrations enhanced antibacterial activity (0.78 mg mL-1) against Staphylococcus aureus in B. natalensis compared to the control plant extracts. However, there was poor antibacterial activity against Escherichia coli in all the heavy metal-treated plants in B. natalensis. Application of Cd and AL at low concentration in D. elata enhanced good antibacterial activity (0.78 mg mL-1) against E. coli which is less susceptible to antibiotics than S. aureus. Extracts from all Cd-treated plants as well as low and moderate Al-treated H. hemerocallidea plants exhibited the good antibacterial activity against S. aureus compared to the control plants. Plants treated with the combined Cd 2:Al 500 mg L-1 treatment also had good activity against S. aureus. However, all the extracts of H. hemerocallidea exhibited poor activity against E. coli. The responses of plants to Cd and Al varied depending on the species. Their ability to accumulate elevated levels of heavy metals raises concerns not only on the safety of these products but also the issues regarding the quality and efficacy of plants grown on heavy metal contaminated soils. The findings presented in this thesis highlight the need for stringent monitoring of heavy metal contamination in medicinal plant material sold at traditional medicine markets and the need for safe and sustainable cultivation of important medicinal plants. This will ensure that medicinal plant products are of a standard quality, safe from toxic contaminants and consistent in terms of phytochemical compositions.
Impacts of climate change on cowpea (Vigna unguiculata L. Walp) treated with biostimulants.
(2020) Voko, Mxolisi Peter.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Vigna unguiculata L. Walp, commonly known as cowpea, is a warm-season herbaceous legume considered native in Africa and Asia. The crop is traditionally consumed as both a leafy vegetable and staple pulse. Although the growth behaviour and nutritional composition of V. unguiculata have been explored by the research community, information regarding the plant’s response to biostimulants under abiotic stresses remain limited. Therefore, studies of this nature are pertinent, especially in the presence of climate change which manifests into global warming, drought episodes and dissipating of natural resources. Hence, a better understanding of the effects of temperature and drought stress on V. unguiculata physiology, morphology, nutrition and phytochemistry are important to ensure high yields which is important for meeting the goals of global food security. Firstly, this study investigated the effects of seed priming with biostimulants [vermicompost leachate, VCL (1:20 v/v), commercial seaweed extract Kelpak®, KEL (0.6%) and smoke-water, SW (1:1000 v/v)] and distilled water (dH2O) on V. unguiculata germination and seedling parameters under constant day/night temperatures of 30/30, 35/35 and 40/40 °C in Conviron® plant chambers. In addition, hydroponic experiments were set-up to evaluate biostimulant efficacy on rooting. Secondly, post-germination effects of VCL 1:20 (v/v), KEL (0.6%) and SW 1:1000 (v/v) were evaluated under similar temperature conditions to ascertain the influence on morphological parameters 28 days after sowing (DAS). Thirdly, postgermination effects of VCL 1:20 (v/v), KEL (0.6%) and SW 1:1000 (v/v) were investigated under different watering regimes using greenhouse protocols to ascertain biostimulation influence on growth variables and flowering after 13 weeks. Finally, the effects of VCL 1:20 (v/v), KEL (0.6%) and SW 1:1000 (v/v) were tested on V. unguiculata’s photosynthetic pigments [chlorophyll a, b, (a + b) and carotenoids], carbohydrates, proteins and phytochemicals (total phenolics and flavonoids) grown for 11 weeks under different watering regimes in the greenhouse. Despite the biostimulants not differing significantly with the corresponding controls, KEL and SW induced marked germination at 30, 35 and 40 °C while VCL being potent under 30 and 40 °C. Seed priming (i.e. biostimulant and hydropriming) significantly improved shoot length and root length over non-priming, with biostimulant-priming being more effective under 40 °C by also inducing significantly higher leaf number, fresh weights and seedling areas compared to non-primed controls. At 30 °C, priming with the three biostimulants improved peduncle diameter, fresh weight and established a significant increase on root length and dry biomass over hydropriming. VCL was most effective at promoting shoot length, root elongation and dry weight under 30 °C while KEL was most effective in increasing seedling leaves, shoot length, root number, fresh and dry biomass of plants exposed to 35 °C. Although overall, biostimulant-non-priming was second best after biostimulantpriming, non-priming with biostimulants was able to promote key variables compared to both controls (i.e. non-primed and hydroprimed controls). Hydroponic results revealed that non-priming with VCL and SW increased root number by 3 and 4-fold, respectively, at 40 °C. SW also stands out at enhancing a significant increase in leaf number and seedling area whereas KEL was the most significant solution promoting shoot length and seedling area. At 30 °C, SW-non-priming promoted significant root elongation, improved fresh and dry weights while VCL was best at promoting root number and root length. KEL and SW also exhibited post-germination effects over the control at 40 °C by improving leaf number on a weekly basis. Fresh and dry weight were improved similarly with significant improvements at 30 °C by KEL and SW. Increasing watering regimes from once to thrice a week significantly increased the number of leaves, root length and flower number. The number of nodules, however, did not differ significantly. Restricting watering frequency to once a week significantly increased shoot length, root length and leaf area in SW-treated plants compared to the control. Shoot length and root length of KEL-treated plants were also increased similarly. Remarkably, VCL increased the number of nodules and shoot length by 4 and 3-fold, respectively. Relative leaf weekly growth in SW, VCL and KEL was higher by 1, 4 and 5 leave(s), respectively, after 11 weeks under high water deficits. This foliage increase remained high by more than 4 leaves in KEL and SW-treated plants watered twice and thrice a week. Accompanying increase in number of flowers was only established in SW water-stressed plants. However, raising watering frequency to twice a week increased flower number in SW, VCL and KEL-treated plants by 2, 4 and 7-fold, respectively, compared to the control. This floral increase was still comparatively high by 2, 4 and 2-fold, respectively, in plants watered thrice a week with biostimulants. VCL also induced a marked significant increase on root length, peduncle diameter and dry weights of plants watered thrice a week. Decreasing substrate water availability from thrice to once a week induced a general increase in leaf soluble proteins, total phenolics and flavonoids. This watering transition significantly enhanced root soluble carbohydrates and proteins while root phenolics and flavonoids markedly declined. VCL, KEL and SW promoted leaf carbohydrates coupled with significant increases in those of roots of SW plants compared to the corresponding controls. Remarkably, leaf soluble proteins of biostimulant plants significantly declined to within the ranges of the plants watered twice and thrice a week. Root proteins were significantly greater to those of leaves in high water-stressed plants and statistically the same to those of roots of plants watered twice and thrice a week. Total phenolics and flavonoids of foliage of the biostimulant plants were lowered and relatively the same in the different watering regimes. Root total phenolics were highly inhibited in less watered plants and gradually increased with an increase in watering regimes. Similar trends were established in flavonoids although they were greater than in the corresponding controls. Biostimulant photosynthetic pigments [i.e. chlorophyll a, b, (a + b) and carotenoid contents] did not differ significantly with those of the control in plants watered once a week. However, the three biostimulants were able to improve chlorophyll a and a + b. KEL and SW induced higher increase in chlorophyll b and carotenoid concentrations. The biostimulants increased chlorophyll a in 3-day-watered plants by more than 2-fold. These biostimulants also improved the chlorophyll a + b and carotenoid contents. Both increasing and decreasing trends in compatible solutes (i.e. soluble sugars and proteins), photosynthetic pigments and phytochemicals under water deficits indicated biostimulant-induced capacity in cowpea for osmotic adjustment, drought tolerance or adaptive mechanisms to water stress. These findings demonstrated the biological potential of VCL, KEL and SW to improve germination, seedling/plant growth and yield in legumes even under temperature stress and drought stress. Thus, establishing their stress amelioration properties to offset negative impacts of climate change on plants and yield.
In vitro bulb induction in Eucomis zambesiaca Baker.
(2009) Cheesman, Lee.; Finnie, Jeffrey Franklin.; Van Staden, Johannes.
Eucomis L’ Hér. is a genus of 10 species that fall within the Hyacinthaceae family. Eucomis zambesiaca Baker is a summer-blooming bulbous geophyte occurring from northern South Africa to Malawi. Eucomis species are used in southern African traditional medicine for the treatment of various ailments, in particular, pain and inflammation. As a result, the bulbs are heavily harvested for trade in South Africa’s traditional ‘muthi’ markets. Over-collection of Eucomis species has seriously depleted natural populations and now Eucomis plants are among the 15 scarcest medicinal species to be traded. Micropropagation is a useful technique for rapid clonal multiplication of plant material which could potentially yield useful secondary metabolites as well as alleviate the pressure on the wild plant populations. The in vitro induction of storage organs is especially beneficial as it can limit the loss of plants during acclimatization as bulblets are hardier than shoots or plantlets. The aim of this research was to determine optimal growth conditions for bulblet induction of Eucomis zambesiaca. The effect of environmental and physiological parameters on the initiation and growth of bulblets was investigated. These included the effect of temperature, photoperiod, various carbohydrates at different concentrations and combinations as well as various plant growth regulators. Maximum number of bulblets per explant was obtained at 20 °C, with an average of three bulbs p er leaf explant. The average bulblet mass was 57 mg, which was significantly higher than bulblets formed at other tested temperatures. An 8 h light regime was the optimum photoperiod. The highest mean number of bulblets (1.4 per leaf explant) developed under the 8 h photoperiod and the bulblets that formed were large in size. They had a mean bulb diameter of 3.4 mm and a mean bulb weight of 42 mg. Different carbohydrates such as fructose, sucrose and glucose were tested at concentrations of; 1, 3, 6, 9 and 12%. Fructose at a concentration of 3% was found to produce the best results. An average of 1.2 bulbs formed per explant. The mean bulb diameter was 3.4 mm and mean bulb weight was 56.6 mg. Plant growth regulators (GA3, IAA, IBA, NAA, BA, zeatin, iP and others) were tested at concentrations of 1, 2 and 5 mg/L. 1 mg/L IBA was found to be the optimum hormone treatment for bulblet induction. Bulblets were large, had good leaves and well established roots. Medium supplemented with 1 mg/L IBA produced bulblets that had an average bulb diameter of 4.36 mm and a mean bulblet weight of 79.1 mg. Bulblets grown in vitro were transferred to vermiculite and placed in a misthouse to acclimatize. After 2 months the plantlets were transferred to pots containing a sand:soil mixture of 1:1 and placed in a greenhouse. There was a 80 to 90% survival rate.
In vitro propagation of Dierama erectum.
(2009) Koetle, Motselisi Jane.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.
Dierama is a genus of plants with a potential to be developed as ornamental plants. It falls under the Iridaceae family and comprises of 44 species. Dierama erectum Hilliard, an attractive species with horticultural potential is mainly found in rough wet grasslands. Its corms are used for enemas and treating stomach ailments in southern African traditional medicine. Due to its habitat transformation by afforestation and the exploitation of its underground parts (corms) in traditional medicine, this plant is among the most vulnerable and rare species within its genus. Seed parasitism by Urodon lilli also hampers its conventional propagation. The increase in demand for ornamental and medicinal plants increases pressure on wild plant populations. Micropropagation is a useful tool for clonal propagation of plants as it does not only help in alleviating pressure on wild plants but an effective micropropagation protocol could also provide a foundation for plant genetic transformation, which could result in the development and introduction of new ornamental varieties into commercial markets. This research was aimed at developing a micropropagation protocol for D. erectum to ensure readily available source material for medicinal and horticultural use as well as serving as an alternative for its conservation. Seed decontamination and germination were successful when 0.2% HgCl2 or 2.5% NaOCl + 1% Benlate® were used. However, for safety reasons, 2.5% NaOCl + 1% Benlate® was used in all subsequent experiments. The shoot regenerative capacity of leaf, hypocotyl and root explants obtained from in vitro germinated seedlings was evaluated by culturing them individually on MS medium supplemented with various concentrations of BA. Only hypocotyl explants produced adventitious shoots. Since no shoots or callus was produced from leaf and root explants, hypocotyl explants were used in the development of a micropropagation protocol. Different types and concentrations of cytokinins (BA, mT, KIN and Z) with or without NAA were evaluated for their effect on adventitious shoot production. Maximum shoot number per explant (4.20 ±0.51) was obtained in MS medium supplemented with 1.0 ìM Z after 8 weeks. This was followed by a combination of KIN (2.0 ìM) and NAA (0.5 ìM) resulting in a production of 3.67 ± 0.81 shoots per explant. For BA treatments, the highest shoot multiplication (3.20 ± 0.22 shoots per explant) was achieved when 2.0 ìM was combined with 1.0 ìM NAA. mT gave maximum shoot production (3.09 ± 0.99 shoots per explant) when 2.0 ìM mT was combined with 2.0 ìM NAA. The effects of photoperiod and light intensity were investigated for the purpose of optimizing shoot multiplication. An average of 12.73 ± 1.03 shoots per explant were obtained after 8 weeks from shoots grown in 16 h light at a 100 ìmol m-2 s-1 light intensity. The 24 h light treatments and a light intensity lower than 100 ìmol m-2 s-1 negatively affected growth and regeneration of D. erectum. These results highlighted the need for evaluating environmental conditions when developing micropropagation protocols. Corm induction experiments were done with the intention of facilitating acclimatization of D. erectum ex vitro. Various concentrations of ancymidol, activated charcoal and sucrose did not promote in vitro corm formation, thus auxins (IAA, IBA and NAA) were tested for their efficiency in rooting. Plants rooted successfully after 8 weeks on MS medium supplemented with 1.0 ìM IBA, yielded the longest roots (4.63 ± 0.70 cm) and an average root number of 2.73 ± 0.40. All NAA treatments resulted in stunted roots. Plants grown in vitro were potted in trays containing a 1:1 ratio of soil: vermiculite and placed in the mist house for 2 weeks. They were then transferred to the greenhouse for further acclimatization. After 2 months, plants had formed corms. The largest corms (0.45 ± 0.026 cm in diameter) were found in plants pre-treated with 0.5 ìM IBA. Maximum plant survival percentage (73%) was also associated with this treatment. A successful micropropagation system for Dierama erectum was therefore developed. The utilisation of this protocol can yield about 15137 plants from one explant in a year. This will expand our existing knowledge about micropropagation of plants in the genus Dierama and will be useful in the conservation of this species.
In vitro propagation of eucalytpus clones using a temporary immersion bioreactor system (RITA)
(2003) McAlister, Brenda Gay.; Finnie, Jeffrey Franklin.; Watt, Maria Paula Mousaco Deoliveira.
Breeding and clonal programs in South African Forestry industry are designed to provide genetically superior trees to supply the forest product industry. Applied biotechnology, and in particular tissue culture, has been used to increase productivity in Eucalyptus clones (genetically superior trees) for trials and clonal hedges for commercial production. Improved growth using bioreactors has been increasingly recognized and the traditional semi-solid culture system was evaluated against a temporary immersion bioreactor (RITA®) system. The temporary immersion bio reactor (RITA®) system was tested across different clones for: ease of initiation into the vessels; multiplication numbers required to achieve production targets; and rooting. In addition costs of the RITA® system were evaluated. Contaminant free shoots in the RITA® system were obtained by initiating shoots on a semi-solid medium and thereafter pre-treating with 0.1 g.1¯¹ Rifampicin in liquid MS medium with visual selection of contaminant free plants. Cultures with fungal contamination were discarded as fungicides used as preventives or curatives measures were found to be ineffective against fungal contamination. Bacterial contamination could be reduced or controlled with the use of 0.1 g.1¯¹ Rifampicin. This however sometimes led to a fungal flush or, if Rifampicin was removed, a flush of bacterial contamination then occurred. Factors such as vessel ventilation, times of immersion and rest, size of vessel, ability to have a liquid substrate rather than a semi-solid substrate, and the physical covering of the plants with the nutrients, led to increased multiplication. Number of ex plants at the start, medium composition and flush and interval times particularly influenced multiplication. Initiating 50 shoots in a vessel with a flush time of 30 seconds and a rest period of 10 minutes gave the highest multiplication (3.8x) after 14 days. Depending on the clone, various media tested had different effects on multiplication. However, MURASHIGE & SKOOG (1962) medium with the following added: 0.1 g.1¯¹ Biotin and Calcium pantothenate; 0.2 mg.1¯¹ BA; 0.01 mg.1¯¹ NAA; and 25 g.1¯¹ sucrose (M1 medium) for both cold-tolerant and sub-tropical clones gave the highest average multiplication after 14 days (5.63x). Maximum shoot multiplication was achieved over 14 to 21 days. After 21 days the nutrients were depleted and the plants began to senesce by day 28. The time period for multiplication in the RITA® system was shorter than for in vitro propagation on semi-solid medium, with improved multiplication in half the time using the RITA® system. Nutrients from the media were utilized at different rates in the two systems. Plants from the RITA® system were superior in quality and this had a positive effect on rooting. The size of the shoot was important for rooting and thus elongation media were tested prior to rooting, with MS and ½ MS giving the best elongation. For rooting in the RITA® system, 1 mg.1¯¹ IBA for two cold-tolerant and one sub-tropical clones gave an average of 66 % normal rooting in the vessels. The type of media used prior to rooting affected rooting and acclimatization percentages. M1 media for 14 days transferring to MS media for 14 days and then placement onto RM media for a further 14 days gave the highest rooting percentage (55 %) after 28 days in the greenhouse. The period of time that the plants were exposed to a particular media played a role in rooting, as did the size of the plants, with bigger shoots (three to seven centimeters) resulting in better rooting. Sub-tropical clones showed no differences in rooting percentages between the semi-solid and the RITA® system rooting environments. However with the cold tolerant clones rooting was substantially improved with the RITA® system. The plants produced in the RITA® system were of a superior quality and acclimatized more readily than those grown on the semi-solid system. The costs involved in producing plants in the RITA® system were lower, as more plants were produced from the medium in shorter time. Although the initial outlay of vessels for the RITA® system was high, it was offset by reduced labour and media cost, together with significantly higher rooting and survival percentages, thus making the RITA® system a very cost effective option for in vitro propagation of Eucalyptus clones.
In vitro propagation, phytochemistry and pharmacology of the blood lily, Scadoxus puniceus.
(2016) Naidoo, Devashan.; Finnie, Jeffrey Franklin.; Van Staden, Johannes.
Abstract available in PDF file.