MSc (Botany) / Department of Botany / Diabetes and arthritis are the most common chronic diseases. Arthritis is the leading cause of global disability and diabetes has become a major health problem which is increasing rapidly. The purpose of the study was to document medicinal plants that are used to treat and manage diabetes and arthritis by traditional medicinal practitioners around the Vhembe District Municipality as well as to evaluate their in vitro efficacy. Traditional practitioners were interviewed using semi-structured questionnaires. Seventeen plant species belonging to fourteen different families were found to be used in the treatment of diabetes as well as arthritis. Fabaceae family was dominating. Antioxidant, anti-inflammatory, cytotoxicity, alphaamylase and alpha-glucosidase) of five plant species, (Bridellia mollis, Elephantorrihiza burkei, Elaeodendron transvaalense, Senna petersiana and Searsia lancea) used traditionally to manage diabetes were investigated using the standard in vitro procedures. All extracts showed a good nitric oxide inhibition, with highest percentage inhibition found in the highest concentration of 100 μg/ml. They all had good percentage cell viability at lowest concentration which was comparable to quercetin. Only two plant extracts B. mollis (T2) and E. transvaalense (T3) had lower than inhibition of quercetin at 25 μg/ml than at 12.5 μg/ml. In vero cells low toxicity effect was observed at lowest concentration tested, and toxicity increased with the increase in concentration. In bovine dermis cell line all plant extracts had more cell viability at lower concentration than doxorubicin. Ethanol extracts of B. mollis and S. petersiana, and ethyl extract of E. transvaalense had a good alpha-amylase inhibitory activity with IC50 values 58.6, 81.9 and 131.5 mg/ml respectively. Hydro-ethanol, ethyl acetate and ethanol extracts of E. burkei exhibited a significant alpha-glucosidase inhibitory activity with IC50 values 56.9, 52.2 and 129.7 mg/ml respectively. Kinetic analysis revealed non-competitive and un-competitive inhibitions of the plant extracts on alpha-amylase and alpha-glucosidase enzymes respectively. The information obtained showed that people in Vhembe District Municipality still rely on medicinal plants to treat and manage diabetes and arthritis. All plant extracts were toxic to both bovine dermis and vero cell lines. S. lancea (T5) was found to be the most toxic plant extract. The observed good inhibitions of both alpha-amylase and alpha-glucosidase enzymes by plant extracts of B. mollis, S. petersiana, E. transvaalense and E. burkei validate their use in the traditional treatment of diabetes in the region to some extent. Aqueous extracts of these medicinal plants should also be investigated because water is the main solvent which is used by traditional practitioners in the preparation of their herbal medicines.

PhD (Microbiology) / Department of Microbiology / See the attached abstract below

MSc (Microbiology) / Department of Microbiology / BACKGROUND: Medicinal plants form an important part of the Southern African cultural heritage. Indigenous populations, for example the Vha-Venda people, tend to use medicinal plants in formulations rather than western medicines for health and survival. In order to certify and give scientific credibility to the use of medicinal plants formulations used by Vha-Venda people for the treatment of diseases, several assays were carried out. The present study was aimed at assessing phytochemical content, antimicrobial, antioxidant and cytotoxic activities of four indigenous Venda medicinal plants in a formulation and compare their activity with each plant used individually. METHODS: Peltophorum africanum (roots), Pterocarpus angolensis (bark), Terminalia sericea (roots) and Ximenia caffra (roots) were collected from the Thohoyandou area. The collected plant parts were extracted with methanol and water respectively. Individual plant extracts and Five designed formulations were tested for their antimicrobial activity against Staphylococcus aureus ATCC 25923 (Methicillin Resistant), Staphylococcus aureus ATCC 33591(Methicillin Susceptible), beta lactamase producing Klebsiella pneumonia (ATCC 700603) and extended spectrum beta lactamase producing E. coli (ATCC 35218), four clinical isolates of Candida spp and Cryptococcus neoformans using the Broth dilution method. Minimum bactericidal concentration (MBC) of the extracts was determined by culturing the contents of minimum inhibitory concentration (MIC) on nutrient agar. Similarly, minimum fungicidal concentration (MFC) was also determined by culturing contents of MIC in sabouraud dextrose agar (SDA). Extracts were further assessed for their total phenolic content, total flavonoid content and Qualitative phytochemical analysis. The antioxidant ability of the plants extracts and formulations to scavenge free radical DPPH was also determined. The plant formulations were assessed for their anti-HIV activity using the reverse transcriptase colorimetric assay kit. Cytotoxicity against human lymphatic endothelial cells (HLEC) was determined using MTT assay. RESULTS: Methanolic and aqueous extracts of T. sericea exhibited the best antifungal and antibacterial activities whilst P. angolensis and X. caffra showed poor activities. Methanolic plant formulations showed good activities compared to aqueous formulations. However, Fractional Inhibition Concentration Index showed that there was 1 synergistic interaction, 25 additive interactions and 14 antagonistic interactions between the plant extracts. The methanolic formulation 3 showed the best overall phenolic content at 11.85±0.109 mgGAE/g whilst aqueous X. caffra extract showed the least content at 4.546±0.104 mgGAE/g. Higher total flavonoid contents were seen in methanolic formulation 4 at 2.75±0.02 mgQE/g. Qualitative phytochemical analysis revealed the presence of flavonoids, phenolics, terpenoids, tannins, saponins and steroids in 80% of the tested plant extracts and formulations. All plant extracts and formulations exhibited good antioxidant activity against DPPH. The methanolic formulation showed the best antioxidant activity with IC50 of 0.094 ± 0.33μg/ml. For anti- HIV inhibition, all formulations at 200μg/ml exhibited higher percentage of HIV-1 reverse transcriptase inhibition with methanolic mixture 3 being the best overall at 97.5% activity whilst aqueous mixture5 was the least active with 63.03% inhibition activity. Moreover, the best anti-HIV activity at 100μg/ml was exhibited by methanolic mixture 3 at 71% inhibition. Furthermore, aqueous X. caffra, mixture 2 inhibited 26% and 51% at 12.5mg/ml and 3.125mg/ml respectively. Peltophorum africanum and mixture 5 inhibited 34%, 54% and 43% at 3.125mg/ml, 6.25mg/ml and 12.5 mg/ml respectively of Human Lymphatic Endothelial cells growth. CONCLUSIONS: The results from the study indicated that most of the commonly used traditional medicinal Plants in the Venda region when mixed together have merit for use in traditional medical practice as they have shown good antimicrobial activities, good antioxidant xviii activities, good phytochemical activities and good cell proliferation activity. However some formulations showed antagonistic interaction against bacteria. Some Individual medicinal plants showed toxicity at higher concentrations against immune cells. Whereas formulations promoted cell proliferation, therefore, the use of such individual plants in the treatment of infections should be highly monitored as they may pose a health threat to normal immune cells. Generally, plants are potential pharmacological agents which needs to be preserved and harvested with care. / NRF

MSc (Microbiology) / Department of Microbiology / Background: The medicinal value of plants lies in some chemical substances that produce a definite physiological action in the human body. The secondary metabolites help the plants to survive hash conditions and could be used by humans as supplements of their health, as foods additives or for medicinal purposes. This bioactive compounds are not always beneficial to human beings, and some of this plants bioactive compounds can be toxic or genotoxic to human cells. This study used several methods to evaluate of phytochemical constituents and mutagenic properties of Coccinia rehmanni and Jatropha zeyheri plant extracts. Methodology: Methanol was used for extraction of the bioactive compounds from the two selected plants, filtered with Whatman filter paper and evaporated with rotary evaporator. The extracts were fractionated using open column chromatography. Chemical and TLC methods were used to determine phytochemicals of the study plants extracts and fractions. The plants extracts and fractions were tested against Vero cell lines in order to evaluate cytotoxicity and genotoxicity of the plants. NucRed and LTR Hoechst 33342 dyes were used for cytotoxicity and genotoxicity respectively. For the evaluation of cytotoxicity and genotoxicity Quantification of live and dead cells for the screening assay was performed using the ImageXpress Micro XLS Widefield Microscope and acquired images analyses using the MetaXpress software and Multi-Wavelength Cell Scoring Application Module. Antimutagenicity of plants extracts was observed using PARP universal colorimetric assay kit. Acquired data was transferred to an EXCEL spreadsheet and data was analyzed. Results and discussion: C. rehmanni (12.03%) yielded more extract than J. Zeyheri (8.20%). the two plants had different compound composition and were in different stages of maturity. The study revealed the domination of Terpenoids, Cardiac glycosides, Phenolic and tannis. With an exception of two fraction fractions all the fractions was found to be toxic to an extent were genotoxicity of such fraction could not be concluded. The reason for such extreme toxicity could be due to the influence of the retained alcohol during rotary evaporation. xvi | P a g e Conclusion: this study provides and add to existing knowledge on the phytochemicals mutagenicity and anti-mutagenicity of C. rehmanni and J. Zeyheri medicinal plants. The study serves as scientific proof that extensive use of this plant in traditional medicine for treatment of various ailments may lead to some irreversible damages. / NRF

See the attached abstract below

MSc (Microbiology) / Department of Microbiology / BACKGROUND: Antibiotic resistance amongst microbial pathogens has become a challenge over past decades, bringing about genuine and frequently deadly contaminations that can't be dealt with by ordinary means. This has led to a search on developing solutions to this problem by searching for new source of antimicrobial agents or chemically altering the existing ones. Traditional medicinal plants and nanoparticles are highly targeted as promising agents to address the challenge. Pyrenacantha grandiflora Baill from Icacenaceae family possess pharmaceutical activities and is used by Vhavenda people to cure gastrointestinal related infections, diarrhea and tooth pain. OBJECTIVES: The present study aimed to synthesize, characterize and evaluate the efficacy of Pyranacantha grandiflora extracts alone and when conjugated with selected nanoparticles against pathogenic microorganisms. Furthermore, this study investigated the efficacy of selected antibiotics when conjugated with nanoparticles against selected pathogenic microbes. METHODS: Pyrenacantha grandiflora Baill (tubers) were collected from Masisi area. Bioactive compounds were extracted using different solvents such as methanol, acetone, hot water, dichloromethane and chloroform. Preliminary phytochemical screening was done to identify different phytochemicals in the extracts and their functional groups were identified by Fourier Transform Infrared spectroscopy (FTIR). Extracts were further assessed for their total phenolic and flavonoids content. Thin layer chromatography was used to separate the compounds from the plant extracts and active compounds/group of compounds were identified by bioautography. The antioxidant ability of the extracts to scavenge free radical DPPH was also determined. Silver and gold nanoparticles were synthesized using chemical and biological methods, characterized by Ultraviolet-Visible Spectrophotometry (UV-VIS), Transmission Electron Microscopy (TEM) and Energy dispersive X-ray analysis (EDX). Plant extracts, nanoparticles and antibiotics were xix conjugated differently, and conjugates were analyzed by FTIR and their antimicrobial activities were evaluated against different bacteria and fungi. The conjugates were tested for antimicrobial activity against extended beta-lactamase producing Escherichia coli (ATCC 35218), Escherichia coli (ATCC 25922), methicillin-resistant Staphylococcus aureus (ATCC 25923), methicillin-susceptible Staphylococcus aureus (ATCC 33591) and beta-lactamase producing Klebsiella pneumonia (ATCC 700603) using agar diffusion assay and the minimum inhibitory concentrations (MIC) were determined using the microdilution method. The minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were determined by sub-culturing from the MIC plates on Mueller-Hinton Agar. RESULTS: Pyrenacantha grandiflora was found to contain phenolics, saponins, alkaloids, tannin, steroids, terpenoids and flavonoids. FTIR spectroscopic studies revealed different characteristic peak values with various functional compounds similar in most extracts but differed with transmittance values. The total phenolic contents in the examined extracts ranged from 14.167 to 19.02 mg GA/g. The total flavonoid content in the examined extracts ranged from 26.603 to 34.621 mg QE/g. Thin-layer chromatography revealed various Rf values and when analyzed with bioautography, well-defined inhibition zones within the Rf value of 0.236 was identified against E. coli and K. pneumonia. The MICs of the extracts were determined, and all the extracts showed some antimicrobial activity against all tested strains ranging from 0.06-7.5 mg ml/g. Some extracts appeared to be fungicidal and hot water extracts were more active against Cryptococcus neoformans with the MFC value of 0.06 mg/ml. The methanol extract was also active against most tested strains including Candida tropicalis with the minimum fungicidal concentration value of 3.75 mg/ml. Pyrenacantha grandiflora tuber extracts conjugated with silver or gold nanoparticles exhibited a good antibacterial activity against all bacterial strain used and very few were able to exhibit bactericidal activity. Penicillin showed improvement of antibacterial activity xx when conjugated with compounds from the acetone extracts and vancomycin was found to be more effective when conjugated with silver nanoparticles and water extracts. CONCLUSION: The present study validated the efficacy of conjugated P. grandiflora tuber extracts which is used in traditional medicine. The results revealed that water extracts which are generally used by the traditional healers are active against most microorganisms tested as well as methanol and acetone extracts and the synergistic effect was observed when they were conjugated to gold and silver nanoparticles. The results of the present investigation clearly indicate that antimicrobial activity of Pyrenacantha grandiflora Baill tuber when conjugated with selected nanoparticles and antibiotics vary with test strain and the type of solvent used during extraction, thus giving hope for future development of drug leads. / NRF

Medicinal plants of Thulamela municipality are experiencing challenges due to human activities, resulting in some of the medicinal plants becoming difficult to find, declining, endangered or even extinct. Unsustainable harvesting is threatening the survival of certain medicinal plant species used as a source of primary healthcare in the area. This study investigates aspects related to traditional healers' perceptions with regard to collection, ethnobotanical importance and conservation status of indigenous medicinal plants used by traditional healers around Thulamela municipality. Information on medicinal plants was gathered by means of semi-structured interviews, field walks, personal observation and a literature review. A total of 90 medicinal plant species, which belong to 47 families, from a total of 82 genera commonly used by traditional healers to treat different ailments, were recorded. About 87% of traditional healers indicated that some medicinal plants are difficult to find; only 13% of healers did not experience difficulties in finding some medicinal plants. / Environmental Sciences / M. Sc. (Ornamental Horticulture)