In this thesis I synthesized different aspects related to diversity, distribution, uses and conservation of medicinal plants in Nepal and also have attempted to recommend guidelines for sustainability of two highly used alpine plant species. The over-harvesting or human induced activities are not the only problem for biodiversity but recently invasion of alien species has also emerged as serious problem in Nepal. I thus also attempted to analyze the effect of invasive species on community composition in the last paper. The first two papers deal with diversity, distribution, uses and harvesting. Paper I showed that medicinal plants in Nepal have unimodal relationship with elevation and the maximum total species richness is at 1000 m. Paper II which deals with the uses of medicinal plants in the Humla region, west Nepal showed that there are 161 medicinal plant species belonging to 61 families and 106 genera used for treating 72 human and 7 veterinary ailments. Medicinal plants in Humla were mostly collected in wild. This induces a serious threat to diversity of the medicinal plants and it is therefore necessary to develop proper management guidelines for their harvesting in wild and/or their domestication. Rheum australe, an endemic plant to west Himalayan region, is widely used plant in traditional...

Further mechanistic studies demonstrated that both Radix Rubiae and realgar were capable of inducing cellular apoptosis on HaCaT cells in a dose- and time-dependent manner as shown by morphological inspection, DNA fragmentation, TUNEL assay, cell cycle analysis, annexin V---PI staining and Western blot analysis. HPLC fingerprintings were constructed for quality control of the Radix Rubiae extract using mollugin as the chemical marker. Further phytochemical study found that ethyl acetate fraction of this herb possessed potent growth inhibition on HaCaT cells, with IC50 of 0.9 microg/ml. However, the chemical compounds obtained from commercial sources including mollugin, alizarin, purpurin, and quinizarin failed to induce growth inhibition. Meanwhile, arsenic trioxide, arsenic pentoxide and arsenic iodide, three arsenic salts presented in realgar, had significant anti-proliferative effect on HaCaT cells, with IC50 values of 2.4, 16 and 6.8 microM, respectively; and cellular apoptosis was found to be the underlying mechanism for the observed growth inhibitory activity. Furthermore, Radix Rubiae, realgar and arsenic compounds were also revealed to possess growth inhibition when evaluated in a PHA-activated PBMC model, and all of the substances except arsenic pentoxide significantly attenuated the release of inflammatory cytokines such as IFN-y, TNF-alpha and IL-2 in PBMC, indicating an anti-inflammatory effect. The in vivo mouse tail model experiments demonstrated that arsenic trioxide, arsenic pentoxide and arsenic iodide were able to markedly induce mouse tail keratinocyte differentiation, while such differentiation-modulating effect observed in the fraction of Radix Rubiae was only marginal. / In summary, Radix Rubiae and realgar extracts and three arsenic compounds have been identified and characterized as potential anti-psoriatic agents. The discoveries from the present PhD project not only help put the traditional use of these medicinal substances for psoriasis treatment on a scientific footing, but also open up new opportunities for their development into novel anti-psoriatic therapies. / Psoriasis, a chronic inflammatory skin disorder affecting approximately 2-3% of the population worldwide, is characterized histologically by hyperproliferation and aberrant differentiation of epidermal keratinocytes. Many conventional therapies are offered for psoriasis treatment but there exist problems such as unsatisfactory efficacy, side effects and drug resistance. Many patients therefore turn to alternative and complementary medicines for help. Traditionally, Chinese herbal medicine has been extensively used to treat psoriasis and produced promising clinical results. The present PhD study was conducted to investigate psoriasis-treating Chinese herbal medicines with an aim to identify effective anti-psoriatic agents. Sixty Chinese medicinal materials were selected for the screening project based on their ethnomedical use in psoriasis. The ethanolic extracts of these medicinal substances were evaluated for their anti-proliferative action on cultured HaCaT human keratinocytes using microplate SRB and MTT assays. Among them, the root of Rubia cordifolia L. (Radix Rubiae) and realgar were found to have significant anti-proliferative effects, with IC50 values of 1.4 and 6.6 microg/ml, respectively as measured by MTT assay, while they exerted mild significant cytotoxicity on the human fibroblast Hs-68 cell line. / Tse, Wai Pui. / Advisers: C. T. Che; Z. X. Lin. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis submitted in: October 2008. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 298-340). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Chan, Wing Hin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 126-143). / Abstracts in English and Chinese. / Acknowledgement --- p.ii / Abstract --- p.iii / 摘要 --- p.vi / Table of Content --- p.viii / List of Figures --- p.xiv / List of Tables --- p.xvi / Abbreviations --- p.xviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Food and herb authentication --- p.1 / Chapter 1.1.1 --- Background and definition --- p.1 / Chapter 1.1.2 --- Importance of species identification in food and herb authentication --- p.2 / Chapter 1.1.2.1 --- Primary health care --- p.2 / Chapter 1.1.2.2 --- Food and herb safety --- p.3 / Chapter 1.1.2.3 --- Conservation --- p.4 / Chapter 1.1.3 --- Methods for species identification in food and herb authentication --- p.4 / Chapter 1.1.3.1 --- Morphological identification --- p.5 / Chapter 1.1.3.2 --- Chemical analysis --- p.6 / Chapter 1.1.3.3 --- Molecular analysis --- p.9 / Chapter 1.1.4 --- Legislation --- p.11 / Chapter 1.1.4.1 --- Labeling ´ب --- p.11 / Chapter 1.1.4.2 --- Chinese medicine : --- p.12 / Chapter 1.1.4.3 --- Conservation --- p.12 / Chapter 1.2 --- Dongchongxiacao --- p.13 / Chapter 1.2.1 --- Background information of Dongchongxiacao --- p.13 / Chapter 1.2.2 --- Classification of fungal part of Dongchongxiacao --- p.14 / Chapter 1.2.3 --- Dongchongxiacao as a Traditional Chinese Medicine. --- p.15 / Chapter 1.2.4 --- The Dongchongxiacao market --- p.16 / Chapter 1.2.5 --- Adulteration and contamination of Dongchongxiacao --- p.18 / Chapter 1.2.6 --- Authentication of Dongchongxiacao --- p.19 / Chapter 1.2.6.1 --- Morphological identification --- p.19 / Chapter 1.2.6.2 --- Chemical analysis --- p.20 / Chapter 1.2.6.3 --- Molecular analysis --- p.22 / Chapter 1.2.6.3.1 --- "FINS analysis with genomic ITS, nrLSU, EF-lα and rpbl regions for fungal analyses" --- p.22 / Chapter 1.2.6.3.2 --- FINS analysis with mitochondrial CytB and COI regions for caterpillar analyses --- p.24 / Chapter 1.3 --- Abalone --- p.26 / Chapter 1.3.1 --- Background information of abalone --- p.26 / Chapter 1.3.2 --- Abalone as food --- p.27 / Chapter 1.3.3 --- The abalone market --- p.28 / Chapter 1.3.4 --- Adulteration of abalone --- p.31 / Chapter 1.3.5 --- Authentication of abalone --- p.32 / Chapter 1.3.5.1 --- Morphological identification --- p.32 / Chapter 1.3.5.2 --- Chemical analysis --- p.32 / Chapter 1.3.5.3 --- Molecular analysis --- p.33 / Chapter 1.3.5.3.1 --- FINS analysis with mitochondrial COI and 16S rDNA --- p.33 / Chapter 1.3.5.3.2 --- Haliotis-specific detection --- p.34 / Chapter 1.4 --- Aim and Objectives --- p.35 / Chapter Chapter 2 --- Materials and Methods --- p.36 / Chapter 2.1 --- Materials used in this sutdy --- p.36 / Chapter 2.1.1 --- Dongchongxiacao and Cordyceps samples --- p.36 / Chapter 2.1.2 --- Downloaded sequences from NCBI database included in Dongchongxiacao study. --- p.45 / Chapter 2.1.3 --- Abalone and gastropod samples --- p.48 / Chapter 2.1.4 --- Downloaded sequences from NCBI database included in abalone study --- p.54 / Chapter 2.2 --- Reagents and equipments : --- p.56 / Chapter 2.2.1 --- Chemical test on the presence of potassium alum in Dongchongxiacao --- p.56 / Chapter 2.2.2 --- Sample preparation and DNA extraction --- p.57 / Chapter 2.2.3 --- Polymerase Chain Reaction --- p.57 / Chapter 2.2.4 --- Agarose gel electrophoresis and Gene Clean --- p.57 / Chapter 2.2.5 --- Cloning --- p.58 / Chapter 2.2.6 --- Cycle sequencing --- p.58 / Chapter 2.3 --- Experimental procedures --- p.58 / Chapter 2.3.1 --- Morphological observation of Dongchongxiacao and abalone --- p.59 / Chapter 2.3.2 --- Chemical test of potassium in Dongchongxiacao --- p.59 / Chapter 2.3.3 --- Sample preparation and DNA extraction --- p.60 / Chapter 2.3.4 --- Polymerase Chain Reaction --- p.61 / Chapter 2.3.5 --- Agarose gel electrophoresis and Gene Clean --- p.64 / Chapter 2.3.6 --- Cloning --- p.65 / Chapter 2.3.7 --- Cycle sequencing --- p.67 / Chapter 2.3.8 --- Sequence analyses --- p.67 / Chapter 2.3.9 --- Haliotis-specific primer design and PCR test --- p.68 / Chapter Chapter 3 --- Results --- p.71 / Chapter 3.1 --- Dongchongxiacao --- p.71 / Chapter 3.1.1 --- Morphological observations --- p.71 / Chapter 3.1.2 --- Chemical test of potassium alum --- p.77 / Chapter 3.1.3 --- Sequence analyses --- p.79 / Chapter 3.1.4 --- The dendrograms --- p.81 / Chapter 3.2 --- Abalone --- p.91 / Chapter 3.2.1 --- Morphological observations --- p.91 / Chapter 3.2.2 --- Sequence analyses --- p.92 / Chapter 3.2.3 --- The dendrograms --- p.94 / Chapter 3.2.4 --- Haliotis-specific PCR --- p.96 / Chapter Chapter 4 --- Discussion --- p.98 / Chapter 4.1 --- Dongchongxiacao --- p.98 / Chapter 4.1.1 --- Species identification of Dongchongxiacao and related Cordyceps species --- p.98 / Chapter 4.1.1.1 --- Ophiocordyceps sinensis --- p.98 / Chapter 4.1.1.2 --- Cordyceps gunnii --- p.100 / Chapter 4.1.1.3 --- Metacordyceps taii --- p.102 / Chapter 4.1.1.4 --- Cordyceps militaris --- p.103 / Chapter 4.1.2 --- Adulteration of Dongchongxiacao and labeling --- p.104 / Chapter 4.1.3 --- Hosts of Dongchongxiacao fungi and relationship between them --- p.107 / Chapter 4.2 --- Abalone --- p.109 / Chapter 4.2.1 --- Species identification of abalones and other gastropod species by FINS analysis --- p.109 / Chapter 4.2.1.1 --- Haliotis species --- p.109 / Chapter 4.2.1.1.1 --- Haliotis diversicolor --- p.110 / Chapter 4.2.1.1.2 --- Haliotis discus --- p.110 / Chapter 4.2.1.1.3 --- Haliotis asinina --- p.111 / Chapter 4.2.1.1.4 --- Haliotis rufescens --- p.111 / Chapter 4.2.1.1.5 --- Haliotis midae --- p.111 / Chapter 4.2.1.1.6 --- Haliotis madaka --- p.112 / Chapter 4.2.1.1.7 --- Haliotis rubra --- p.113 / Chapter 4.2.1.1.8 --- Haliotis iris --- p.113 / Chapter 4.2.1.1.9 --- Haliotis corrugata --- p.114 / Chapter 4.2.1.2 --- Concholepas concholepas --- p.114 / Chapter 4.2.1.3 --- Hemifusus species --- p.115 / Chapter 4.2.1.4 --- """Dried abalone slice"" samples (D1 to D3) and canned top-shell (E5)" --- p.115 / Chapter 4.2.2 --- Haliotis-speciflc PCR --- p.115 / Chapter 4.2.3 --- Adulteration of abalone and labeling --- p.116 / Chapter 4.3 --- Significance and limitation of molecular approaches in authentication of food and herbs --- p.117 / Chapter 4.3.1 --- FINS analysis --- p.117 / Chapter 4.3.1.1 --- High interspecific variability but low intraspecific variations --- p.118 / Chapter 4.3.1.2 --- Amplification with universal primers --- p.118 / Chapter 4.3.1.3 --- Insufficient DNA sequence available in database --- p.119 / Chapter 4.3.1.4 --- Contamination by foreign DNA and amplification of undesirable DNA in sample mixture --- p.120 / Chapter 4.3.1.5 --- Amplification of degraded DNA --- p.121 / Chapter 4.3.1.6 --- Suggested regions for authentication of Dongchongxiacao and abalone based on FINS analysis results --- p.121 / Chapter 4.3.2 --- PCR with specific primers for targeted amplicons --- p.122 / Chapter 4.3.3 --- Other limitations of molecular approaches in authentication of food and herbs --- p.123 / Chapter 4.4 --- Further investigation --- p.124 / Chapter 4.5 --- Conclusion --- p.124 / References : --- p.126 / Chapter Appendix 1 --- Sequence alignment of 16S rDNA gene sequences of abalone for Haliotis-specific primer design --- p.144 / Chapter Appendix 2 --- Accession numbers of sequences of Dongchongxiacao and Cordyceps samples in this study --- p.149 / Chapter Appendix 3 --- Search results of CytB sequences of caterpillar host of Cordyceps samples based on BLAST search results from GenBank --- p.150 / Chapter Appendix 4 --- Search results of COI sequences of caterpillar host of Cordyceps samples based on BLAST search results from GenBank --- p.151 / Chapter Appendix 5 --- Search results of COI sequences of caterpillar host of Cordyceps samples based on BLAST search results from GenBank --- p.152 / Chapter Appendix 6 --- Sequence alignment of ITS sequences of Cordyceps samples and related sequences --- p.153 / Chapter Appendix 7 --- Sequence alignment of nrLSU sequences of Cordyceps samples and related sequences --- p.161 / Chapter Appendix 8 --- Sequence alignment of EF-lα sequences of Cordyceps samples and related sequences --- p.168 / Chapter Appendix 9 --- Sequence alignment of rpbl sequences of Cordyceps samples and related sequences --- p.173 / Chapter Appendix 10 --- "Sequence alignment of combined dataset of three regions (nrLSU, EF-lα and rpbl) of Cordyceps samples and related sequences" --- p.179 / Chapter Appendix 11 --- Sequences alignment of CytB sequences of caterpillar host of Cordyceps samples and related sequences --- p.188 / Chapter Appendix 12 --- Sequence alignment of COI sequences of caterpillar host of Cordyceps samples and related sequences --- p.191 / Chapter Appendix 13 --- Sequence alignment of COI sequences of Cordyceps samples D12-2 and D14 and related sequences --- p.195 / Chapter Appendix 14 --- Sequence distance matrix of ITS sequences of Cordyceps samples and related samples based on K2P algorithm --- p.196 / Chapter Appendix 15 --- Sequence distance matrix of nrLSU sequences of Cordyceps samples and related samples based on K2P algorithm --- p.203 / Chapter Appendix 16 --- Sequence distance matrix of EF-lα sequences of Cordyceps samples and related samples based on K2P algorithm --- p.208 / Chapter Appendix 17 --- Sequence distance matrix of rpbl sequences of Cordyceps samples and related samples based on K2P algorithm --- p.213 / Chapter Appendix 18 --- "Sequence distance matrix of combined dataset of three regions (nrLSU, EF-lα and rpbl) sequences of Cordyceps samples and related samples based on K2P algorithm" --- p.217 / Chapter Appendix 19 --- Sequence distance matrix of CytB sequences of caterpillar host of Cordyceps samples and related samples based on K2P algorithm --- p.219 / Chapter Appendix 20 --- Sequence distance matrix of COI sequences of caterpillar host of Cordyceps samples and related samples based on K2P algorithm --- p.223 / Chapter Appendix 21 --- Sequence alignment of chloroplast trnH-psbA sequences of Cordyceps sample D12-2 and related sequences --- p.226 / Chapter Appendix 22 --- Accession numbers of sequences of abalone and gastropod samples in this study --- p.227 / Chapter Appendix 23 --- Search results of 16S rDNA sequences of the abalone and gastropod samples based on BLAST search results from GenBank --- p.228 / Chapter Appendix 24 --- Search results of COI sequences of the abalone and gastropod samples based on BLAST search results from GenBank --- p.229 / Chapter Appendix 25 --- Search results of COI sequences of the abalone and gastropod samples based on BOLD-IDS --- p.230 / Chapter Appendix 26 --- Sequence alignment of 16S sequences of abalone samples and related sequences --- p.231 / Chapter Appendix 27 --- Sequence alignment of COI sequences of abalone samples and related sequences --- p.234 / Chapter Appendix 28 --- Sequence alignment of COI sequences of abalone product sample D2 and related sequences --- p.238 / Chapter Appendix 29 --- Sequence distance matrix of 16S sequences of abalone samples and related samples based on K2P algorithm --- p.239 / Chapter Appendix 30 --- Sequence distance matrix of COI sequences of abalone samples and related samples based on K2P algorithm --- p.243

Thesis (M.Sc. (Biochemistry)) --University of Limpopo, 2017 / Cancer is a broad group of various diseases characterised by unregulated cell proliferation which leads to the formation of tumours (Vickers, 2004). Some tumours remain confined to their site of origin while some gain the ability to spread to other parts of the body, a process known as metastasis (Weiss, 1990). The burden of cancer continues to rise, due to inefficient prevention strategies and serious side effects, as well as the cost of cancer regimens (Sondhi et al., 2010). Medicinal plants represent a reservoir of bioactive compounds that can be useful in the management of cancer with less or no side effects (Wong et al., 2012). The aim of this study was to investigate the anti-cancer effects of M. balsamina leaf extract in breast MCF-7 cancer cells. In this study, M. balsamina leaves powder was extracted using acetone. The biological effect of the extract was assessed on the viability of MCF-7 cells using the MTT assay. The extract’s ability to induce apoptosis was assessed using the Hoechst/propidium iodide dual staining method. Its anti-metastatic potential was investigated by determining its effect on MCF-7 cell migration, attachment and invasion using wound healing, adhesion, invasion assay, respectively. The human apoptosis antibody and human angiogenesis antibody array kits were used to determine the effect of the extract on the expression levels of proteins involved in apoptosis and metastasis, respectively. Treatment of MCF-7 cells with different concentrations of the extract showed a significant decrease in cell viability after 48 h incubation at 10 - 20 µg/ml. The decrease in cell viability was associated with the induction of apoptosis as seen by nuclear condensation and loss of membrane permeability in cells treated with the extract. Inhibition of migration, adhesion and invasiveness of the MCF-7 cells was seen in the treated cells. The extract also modulated proteins implicated in cell apoptosis, adhesion, migration and invasion such as Bcl-2 family of proteins, IGFBP, uPA, MMPs. In conclusion, based on the results, the extract show pro-apoptotic and anti-metastasis potential. Thus M. balsamina can be considered as a potential source of compounds with anti-cancer activity

Thesis (Ph. D. (Microbiology)) --University of Limpopo, 2019 / Tuberculosis (TB) is one of the top ten diseases that causes morbidity and mortality worldwide. Although TB is curable, the main problem currently with TB is development resistance to the current chemotherapy. Medicinal plants, as a source of drugs, have been found to cause less or no resistance. Medicinal plants are studied and considered for their efficacy and safety because they possess bioactive compounds with various biological activities. The aim of the study was to isolate and characterise bioactive compounds from selected seven plant species [A. dimidiata (LNBG 1969/46), A. afra (LNBG 2010/27), Z. capense (LNBG 1969/100), C. herorense (LNBG 1977/71), L. javanica (LNBG 1969/460), E. camaldulensis and C. lemon (UNIN 12330)] with activity against Mycobacterium smegmatis, Multi- drug resistant tuberculosis starain and H37Rv Mycobacterium tuberculosis strain. It was also imperative to determine whether crude extracts, sub- fractions of the extracts and the isolated bioactive compounds are cytotoxic or not. Leaves of the seven selected plants were collected from South African National Botanical Institute (SANBI) at Nelspruit, Mpumalanga Province, South Africa. The leaves were dried and milled to fine powder. The leaves of each plant were extracted using solvents of varying polarity (i.e. hexane, dichloromethane, acetone and methanol). Phytochemical screening was done using Thin Layer Chromatography (TLC) developed in three mobile phases varying in polarity and then sprayed with vanillin sulphuric acid in methanol heated at 110oC for optimal colour development. Qualitative antioxidant activity was determined by using 1,2- diphenylpicryl hydrazyl (DPPH) assay on TLC plates. Antimycobacterial activity for all the plant extracts was done using bioautography assay in qualitative analysis of the active compounds and for quantitative analysis, the microplate dilution assay was used. The plants which showed better activity (C. lemon, C. hereroense and A. dimidiata) with the microplate dilution assay and bioautography were further subjected to solvent- solvent fractionation as the first step towards isolation of bioactive compounds. Synergistic, additive, indifferent and antagonistic effects of the crude extracts combinations of the three selected plants was determined. The combinations where A. dimdiata was also part of the combinations frequently showed synergistic effect. On the other hand, with the combinations of C. hereroense and A. dimdidata (CH-AD) there was no antagonistic effect observed. The combinations of crude extracts of C. lemon and A. dimidiata all showed synergistic effect, except for only three combinations. Based on the synergistic effect observed and the bioactivity on the bioautography and microplate dilution assay of the sub- fractions, A. dimidiata was chosen for further analysis for antimycobacterial activity using the MDR- TB strain and M. tuberculosis H37Rv strain. The sub- fractions of A. dimidiata with the most activity were hexane and butanol. Hexane and butanol fractions both showed good MIC activity against the TB isolated M. tuberculosis field strain and H37Rv strain of 0.47 and 031 mg/ml, respectively. Butanol fraction was further taken for isolation using open colum chromatography doing bioassay guided isolation. The isolated compounds, together with the crude were tested for their biological activity using MTT assay to determine their cytotoxicity and antimycobacterial activity assay to confirm their activity against M. smegmatis and M. tuberculosis. Cytotoxicity assay showed that the crude extracts of A. dimidiate were toxic against the Vero kidney cells and the subfractions (i.e. butanol and hexane) became moderate to non-toxic and one compound (oleanolic acid) from the butanol sub-fraction was non- cytotoxic. This indicates that the isolation of the crude extracts tends to become non- toxic to the cells. The study suggests the use of pure compounds to fight against TB as compared to crude extracts since they are both bioactive and non- cytotoxic. Crude extracts combinations were effective in killing Mycobacterium as compared to single crude extracts. The present study recommends the use of A. dimidiata plant leaves crude extracts combinations as they mostly exhibit synergistic effect. Furthermore, Mycobacterium and also contain non- cytotoxic antimycobacterial compound (oleanolic acid). The study serves as a scientific proof for the use of this plant in traditional medicine for TB treatment.

X, 125p / Thesis (M.Sc. (Botany)) --University of Limpopo, Turfloop Campus, 2010 / A study of the role played by muthi shops and street vendors on the trade of indigenous medicinal plants of the Limpopo Province was undertaken in order to develop strategies that will prevent further loss of wild population. This study further investigated the conservation status and in situ availability of targeted medicinal plants, as well as suitable methods to replace wild collections with cultivated ones. Existing environmental legislation was interrogated to ascertain its effectiveness in practice. Nearly 231 medicinal plants were traded at the 16 investigated muthi shops and street vendors, accounting for a calculated 0.96 tonnes of plant material traded annually. Roots were the most preferred item traded. Open access communal lands are the main supply source for muthi markets, coupled with the destructive harvesting methods and involvement of unscrupulous middlemen in collecting medicinal material possesses a serious impact on the survival of medicinal plants. The above factors have already led to a significant decline in the availability of some species in the Limpopo Province. The cultivation of the eight most frequently encountered medicinal species was investigated. Cultivation information provided by indigenous nurseries indicates that medicinal plant species can be cultivated. Efforts to protect species through national and provincial legislation have been ineffective. Environmental laws were totally unknown by all of muthi traders interviewed. Unregulated exploitation of medicinal plants continued regardless of the fact that environmental compliance officers are aware of legislative protection given to specific species and plants in general. Failure to stabilize the status of medicinal plants in Limpopo Province will have not only negative effect on the Province environment, but also on the overall health status of the majority of people living in Limpopo Province. / N/A

Thesis (Ph.D (Plant Physiology) --University of Limpopo, 2006 / Refer to document / National Research Foundation and ARC (Nelspruit)

Diabetes mellitus (DM) has become a global threat in developing and developed countries, where diabetic patients are more prone to cardiovascular complications, a condition called diabetic cardiomyopathy. Studies have shown a direct link between hyperglycaemia and an increase in the production of reactive oxygen species in cardiac cells leading to diabetic cardiomyopathy. This study tests oleanolic acid, a bioactive compound from the plant Syzigium aromaticum as an antioxidant which could have a potential role in management of DM. Aims i) To extract Oleanolic acid (OA) from Syzigium aromaticim, ii) Investigate the antioxidant effects of plant derived OA in an in-vitro model of hyperglycaemia induced oxidative stress. Methods The flower buds of the Syzigium aromaticim [(Linnaeus) Merrill & Perry] (Myrtaceae) plant (commonly called cloves) were used to isolate OA. The ethyl acetate solubles from the cloves were subjected to chromatographic fractionation to yield OA powder. Spectroscopic analysis was done using 1D and 2D 1H and 13C NMR techniques for the identification of the structure of the compound. This compound was then used in vitro to test for its antioxidative properties. H9C2 cardiac myoblasts were employed which were treated with normoglycaemic (5.5 mM) and hyperglycaemic (33 mM) glucose conditions. The cells were then treated with oleanolic acid to test for its antioxidant properties. We looked at a dose-dependent (0, 20, 50 μM) and time-dependent effects of OA treatment (6 and 24 hrs) following 48 hours glucose exposure. ROS levels were measured using H2DCF-DA fluorescence staining using microscopy and flow cytometry techniques for analysis. xviii Results Recrystallisation of the powder with ethanol and inspection of the 1 and 2- dimensional 1H- and 13C-NMR spectra of the compound with comparison to literature data confirmed OA molecular structure and IUPAC numbering similar to that of literature characterized and confirmed the structure of oleanolic acid. In cell specific data high glucose treatments on H9C2 cells showed increased ROS production (22 ± 6 % and 20 ± 7 % n= 3 p< 0.01) for 6 and 24 hrs treatments, respectively, compared to their normoglycaemic control groups. The 6 h OA treated group showed a decrease in ROS production with 26.6 ± 17.4 % for the 20 μM while for 50 μM there was a 37.7 ± 14.3% decrease. A ROS reduction trend was observed in the normoglycaemic group, but this was significant at 24 hrs with 46.8 ± 45.3% and 57.3 ± 9 % for both 20 and 50 μM treatments, respectively. The 24 hrs OA treated group showed a dose-dependent decrease in ROS with 50 μM more pronounced (80.7% ± 4.5 %). The 20 μM OA treatments also showed a 15.7 ± 19 % decrease in ROS. Discussion In the present study, we have evaluated the antioxidant effects of OA in vitro following extraction of the compound from Syzigium aromaticim. The oxidative stress induced by hyperglycaemia was attenuated by oleanolic acid and this also translated into decreased ROS suggesting its use as an antioxidant in alleviating cardiovascular complications associated with diabetes mellitus.

Siphonochilus aethiopicus (Schweinf.) B.L. Burtt (Zingiberaceae), commonly known as wild ginger, is a highly sought after plant for use in traditional medicine in South Africa. Over-exploitation of this medicinal plant has resulted in regional extinction in the wild. As a result, there is great interest in the medicinal properties of S. aethiopicus, and as a plant for small scale cultivation to increase the supply for use in traditional medicine. Water, ethanol and ethyl acetate extracts were prepared from the leaves, rhizomes and roots of S. aethiopicus. These extracts were tested for in vitro anti-inflammatory activity in the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) assays, and in the microdilution antibacterial assay. The aqueous extracts showed no significant prostaglandin synthesis inhibition in the COX-1 and COX-2 assays. The ethanol and ethyl acetate extracts of the leaves showed the highest levels of activity at a concentration of 250 µg ml¯¹ per test solution, in both the COX-1 and COX-2 assays. The ethanol and ethyl acetate extracts of the rhizomes and roots also had moderate levels of activity in the COX-1 assay. These results provide some evidence for the rational use of S. aethiopicus in traditional medicine for anti-inflammatory purposes. In the microdilution antibacterial assay, no inhibitory activity against the test bacteria was detected with the aqueous extracts. The ethanol and ethyl acetate extracts tested showed greater antibacterial activity at minimal inhibitory concentrations ranging from 0.78 to 3.13 mg ml¯¹ against the gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) than the Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae). No distinct differences were observed between the ethanol and ethyl acetate extracts, or between the different plant parts. A serial extraction of S. aethiopicus rhizome material was conducted and the extracts were tested in the COX-1 assay and the microdilution assay as a preliminary investigation for a bulk extraction. The hexane and ethyl acetate extracts gave slightly higher COX-1 inhibition than the ethanol extract. No distinct differences were observed in the microdilution assay. A bulk ethyl acetate extract of S. aethiopicus rhizome material was prepared, yielding 6.3 g of a thin orange oil. Vacuum liquid chromatography (VLC) was used to fractionate ≈4 g of the extract. The VLC fractions were evaluated using thin layer chromatography (TLC) and a bioautographic assay, using S. aureus as a test organism. The fractions were also tested in the COX-1 assay. The bioautography revealed a number of compounds which exhibited antibacterial activity. Fraction C was purified further using preparative TLC, and 24.9 mg of a pure compound from R,0.54 (toluene:ethyl acetate 93:7) was isolated. The structure of the compound was elucidated from nuclear magnetic resonance (NMR) spectra, and mass spectroscopy of the compound was also recorded. The compound was identified as the sesquiterpenoid furanoeremophil-2-en-1-one, which is structurally identical to the recently reported compound 4aαH-3,5α,8aβ-trimethyl-4,4a,9-tetrahydro-naphtho[2,3-b]-furan-8-one. The compound showed only a very minimal bacteriostatic effect in the microdilution assay. S. aethiopicus plants were harvested before and after seasonal senescence. Ethanol extracts were prepared from fresh or dried material of the leaves, rhizomes and roots, and tested in the COX-1 assay and the microdilution assay TLC fingerprints of the various extracts were also prepared. No noteworthy changes in COX-1 inhibition, due to senescence, were observed with extracts prepared from fresh material, although there did appear to be a slight decrease in activity in the α-roots and an increase in the β-roots after senescence (fresh and dry). A decrease in the antibacterial activity of the leaves and an increase in the antibacterial activity of the α-roots was observed after senescence. These results suggest that the time of harvest may only have a minimal influence on the degree of anti-inflammatory and antibacterial activity. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2009. / Full text also available online. Scroll down for electronic link.