The research presented in this study demonstrates the critical role that organic synthesis plays in natural product chemistry. The biological activity demonstrated by 2-methyl-6-(3-methyl-2- butenyl)benzo-1,4-quinone prompted an investigation into the synthesis of this compound. This natural product showed significant activity against Staphylococcus epidermidis. Therefore the aim of this study was to synthesise 2-methyl-6-(3-methyl-2-butenyl)benzo-1,4- quinone and structural analogues. The regioselective synthetic route formulated for the synthesis of 2-methyl-6-(3-methyl-2- butenyl)benzo-1,4-quinone involved five steps. Different strategies towards the synthesis of this compound were investigated. The regioselective C-alkylation step was proving to be the most challenging. The synthetic strategies investigated included carbon alkylation of a phenoxide, directed-o-metallation, metal-halogen exchange and copper(II) Grignard-type metal halogen exchange. Problems were encountered with regioselectivity when carbon alkylation of a phenoxide was employed for the o-prenylation of o-cresol. The C-prenylated isomer was formed along with the O-prenylated isomer. When the reaction temperature was lowered, the yield of the desired C-prenylated isomer improved, whereas the yield of O-prenylated isomer declined. Although the reaction was performed under different conditions, the formation of the O-prenylated isomer could not be prevented. Therefore, another synthetic strategy was considered. The directed-o-metallation reaction was subsequently employed because of the associated regioselectivity. Unfortunately the desired product was not obtained when this method was employed. The reaction was attempted using different conditions, but the product could not be isolated. Since the directed-o-metallation protocol did not yield the desired results, another method was considered. Therefore, a metal-halogen exchange reaction was employed. The metal-halogen exchange transformation was preceded by the preparation of the o-brominated precursor. Regioselectivity-related problems were initially encountered during the synthesis of the obrominated precursor. The o-brominated isomer was formed in a 1:1 ratio with the pbrominated isomer. Further investigation led to a synthetic protocol that afforded the desired o-brominated isomer in a better yield. The metal-halogen exchange transformation was subsequently attempted, but the product was obtained in an unsatisfactory yield. Therefore, another method was employed in an effort to achieve regioselective C-alkylation with a better yield. Copper(II) Grignard-type metal-halogen exchange was successfully employed to achieve regioselective C-alkylation in good yield. The subsequent step was the deprotection, although problems were encountered, it was eventually achieved. The final step was the oxidation to obtain the desired compound, 2-methyl-6-(3-methyl-2-butenyl)benzo-1,4- quinone. The same procedure was successfully applied in the synthesis of structural analogues 2-isopentyl-6-methylbenzo-1,4-quinone, 2-(3,7-dimethylocta-2,6-dienyl)-6-methyl-1,4- benzoquinone and 2-(3,7-dimethyl-octyl)-6-methyl-1,4-benzoquinone. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Ledebouria zebrina and Scilla natalensis Planch were the two species investigated in this work. Ledebouria zebrina belongs to the Hyacinthaceae (Liliacea sensu lato) and to this date, the chemical composition of this species has not been investigated. Members of this family are found in southern Africa. The Ledebouria genus was formerly classified as part of the Scilla genus from which a large member of naturally occuring oxygen heterocycles known as homoisoflavanones have been isolated. In this work the bulbs of L. zebrina were investigated and five compounds were isolated. Three compounds were of the homoisoflavanone type while the remaining two belong to the eucosterol type triterpernoids. Scilla natalensis Planch also belongs to the Hyacinthaceae family. Previous chemical investigations of the bulbs of this plant yield two homoisoflavanones of the 3-benzyl-4- chromanone type. Members of this family are mostly found in the Eastern parts of the country, ranging from the Eastern Cape to Mpumalanga province including Lesotho and Swaziland. The bulbs of this plant were investigated and this yielded ten compounds. The structures of the isolated compounds were elucidated using spectroscopic methods. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Two species belonging to different families were investigated, Eucomis montana from the Hyacinthaceae and Agapanthus inapertus from the Agapanthaceae. To date no previous chemical investigation on Eucomis montana has been reported. Eucomis species are routinely harvested, processed and sold for the treatment of various ailments ranging from toothache, gastro-intestinal ailments, pain-producing ailments and venereal and urinary diseases. Members of the genus have shown to contain steroidal compounds and homoisoflavonoids. In this work one nortriterpenoid, a eucosterol type derivative and eleven homoisoflavonoids belonging to four classes, the 3-benzyl-4-chromanone, the 3-benzyl-3-hydroxy-4-chromanone, the 3-benzylidenyl-4-chromanone and the scillascillin type were found in the bulbs of Eucomis montana. Agapanthus species are also used by a number of African tribes medicinally. The bulbs and rhizomes of this family have been reported to contain steroidal saponins and sapogenins. In this work the roots of Agapanthus inapertus have been investigated and a tignan precursor and a lignan have been found. Structures of the compounds isolated were determined using spectroscopic techniques. / Thesis (M.Sc.)-University of Natal, Durban 2003.

Ph.D. (Botany) / The most well-known tonic plants in South Africa have been used traditionally for the treatment of a great variety of ailments but aspects of their ethnobotany and chemistry remain poorly studied. Possible relationships between their ethnobotany and pharmacology are mostly speculative. In this study, literature reviews of the ethnobotany of these plants were combined with phytochemical screening studies and bitterness taste testing results in order to establish constituent patterns which may contribute to a scientific rationale for the claimed tonic (stimulating) properties of these plants. The tonic concept and definitions of terms associated with it are often used incorrectly and ambiguously. An analysis of literature on the traditional healing systems across the globe was used to establish the historical and cultural aspects relevant to tonics. This analysis revealed that sickness/illness is usually considered to be a result of imbalance in many cultures, whether this imbalance is between the patient and the environment or due to a lack of homeostasis in the body. In several healing cultures substances or mixtures of substances are used to rectify these imbalances through proposed effects on several bodily systems concurrently. According to some cultures, as in Eastern and Indian traditional medicine, tonic plants are considered superior to other medicinal plants in that they impart health, strength and a general sense of well-being, as well as being prophylactic. This definition of a tonic plant is consequently broad, but excludes plants merely used as multipurpose medicines. Where these tonics exhibit a specific mode of action, further classification is required, i.e. as bitter, adaptogenic, alterative, adjuvant or stimulant tonics. The South African traditional tonic plants studied were Agathosma species (Rutaceae), Aloe species (Asphodelaceae), Arctopus species (Apiaceae), Artemisia afra (Asteraceae), Balanites maughamii (Balanitacae), Dicoma species (Asteraceae), Harpagophytum procumbens (Pedaliaceae), Hypoxis hemerocallidea (Hypoxidaceae), Muraltia heisteria (Polygalaceae), Sutherlandia species (Fabaceae), Vernonia oligocephala (Asteraceae), Warburgia salutaris (Canellaceae), Withania somnifera (Solanaceae) and Ziziphus mucronata (Rhamnaceae). A detailed compendium of medicinal applications was compiled following a thorough, in-depth scrutiny of the historical and medicinal ethnobotany of each of these species. Such ethnobotanical data is important in understanding the cultural aspects of healing in southern Africa, and provides valuable direction and focus with regards to the phytochemical and pharmacological research of these plants.

Submitted in fulfillment for the Degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2016. / Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB) has infected approximately one-third of the world population, with 9.6 million TB cases in 2014. The emergence of multi-drug resistant (MDR) and extensively-drug resistant (XDR) strains of MTB has further complicated the problem of TB control. It is now imperative that novel antimycobacterial compounds are discovered in order to treat infections and reduce the duration of current TB therapy courses. For centuries, medicinal plants have been used globally worldwide for the treatment and prevention of various ailments. This occurs particularly in developing countries where infectious diseases are endemic and modern health facilities and services are inadequate. In recent years, the use and search for plant drug derivatives have been fast-tracked. Ethnopharmacologists, botanists, microbiologists, and natural product chemists are trying to discover phytochemicals which could be developed for the treatment of infectious diseases, especially TB. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimycobacterial activity. In the search for new lead compounds, nine medicinal plant species, Buddleja saligna, Capparis tomentosa, Carpobrotus dimidiatus, Dichrostachys cinerea, Ekerbergia capensis, Ficus Sur, Gunnera perpensa, Leonotis leonurus and Tetradenia riparia were collected in Kwa-Zulu Natal (KZN) following report of their therapeutic use in traditional medicine to treat symptoms and infections related to TB. They were tested in vitro for their activity against Mycobacterium smegmatis, Mycobacterium tuberculosis H37Rv (ATCC 25177) and three well-characterized clinical isolates of MDR-TB and XDR-TB using the agar incorporation method. The minimum inhibitory concentration of the active plant extracts was determined using the broth microdilution method. Our findings show that five of the nine plants screened have antimycobacterial activity with concentrations ranging from 125 µg/ml to 1000 µg/ml. The aqueous extracts of G. perpensa and T. riparia; and the methanolic extracts of B. saligna, C. tomentosa, and C. dimidiatus possessed significant activity against M. smegmatis, M. tuberculosis H37Rv (ATCC 25177) and the three well-characterized clinical isolates of MDR-TB and XDR-TB. The cytotoxic effect of the active plant extracts was evaluated against the mouse BALB/C monocyte-macrophage (J774.2) and peripheral blood mononuclear cells (PBMCs). The toxic effects of the active plant extracts were evaluated using the brine shrimp lethality assay. Except for a high concentration of G. perpensa none of the other plants which possessed antimycobacterial activity showed any toxic or cytotoxic activity. The active plant extracts were thereafter assessed to determine if they had any effect on the survival or death of mycobacterial species, M. smegmatis, bound within the macrophage (J774.2) cell line at a concentration of 100 µg/ml. B. saligna had inactivated most of the phagocytosed bacilli after 24 hours of treatment therefore, it has a bactericidal effect on the mycobacteria located within the mouse macrophage. A phytochemical investigation of the leaves of B. saligna led to the isolation of two isomeric pentacyclic triterpene compounds namely Oleanolic Acid (OA) and Ursolic Acid (UA) using thin layer chromatography followed by silica gel column chromatography. The structures of these compounds were fully characterized by detailed NMR investigations, which included 1H and 13C NMR. Ursolic acid was isolated from this plant for the first time. Two-dimensional (2D) and three-dimensional (3D) quantitative structure-activity relationship (QSAR) studies were carried out to provide insight on the interaction of the compounds with the enzyme. Molecular docking studies predicted the free binding energy of the triterpenes inside the steroid binding pocket of Mycobacterium tuberculosis fadA5 thiolase compared to a reported inhibitor. Thus, their ability to inhibit the growth of Mycobacterium tuberculosis was predicted and was confirmed to possess significant antimycobacterial activity when tested against M. smegmatis, M. tuberculosis H37Rv (ATCC 25177), clinical isolates of MDR-TB and XDR-TB using the Microplate Alamar Blue Plate (MABA) assay. The present study has scientifically validated the traditional use of medicinal plant B. saligna. / D

Orientador: Wagner Vilegas / Banca: Ian Castro-Gambôa / Banca: Fernando Batista da Costa / Banca: Mitsue Haraguchi / Banca: André Luiz Meleiro Porto / Resumo: Neste trabalho foram estudadas a composição química e atividades farmacológicas de folhas de Alchornea glandulosa e Alchornea triplinervia (Euphorbiaceae) e partes aéreas de Indigofera truxillensis e Indigofera suffruticosa (Fabaceae), usadas na medicina popular brasileira no tratamento de problemas gástricos. Nos extratos clorofórmicos das espécies de Alchornea foram identificados estigmasterol, campesterol, sitosterol, lupeol, friedelan-3-ol, friedelan-3-ona e pteroginidina. O estudo dos extratos metanólicos das espécies de Alchornea forneceu ácido gálico, galato de metila, ácido carboxílico da brevifolina, amentoflavona, isocorilagina, miricetina 3-O-α-L-raminopiranosídeo, quercetina e quatro derivados glicosilados. Análise por FIA-ESI-IT-MS indicou a presença de derivados do ácido galoilquínico, elagitaninos e proantodicianidinas em A. triplinervia. Nos extratos clorofórmicos das espécies de Indigofera foram identificados índigo (indigotina) e indirubina. O extrato metanólico de I. truxillensis forneceu índigo, indirubina, indicana, pinitol, sitosterol 3-O-β-D-glicopiranosídeo e cinco derivados glicosilados do kaempferol, entre eles a substância inédita kaempferol 3-O-[α-Larabinopiranosil-( 2→1)-α-L-apiofuranosil] -7-O-α-L-raminopiranosídeo. O extrato metanólico de I. suffruticosa forneceu as mesmas substâncias descritas para I. truxillensis, exceto derivados do kaempferol, além do ácido gálico, alantoína e quatro derivados glicosilados da quercetina. Deste extrato também foram isoladas as substâncias inéditas 6'-metoxi 2, 5, 6-triidroxiisoindirubina, indigotina-3-O-β-D- glicopiranosídeo, dioxindol-3-O-β-D-glicopiranosídeo e quercetina 3-O-β-Dglicopiranosil-[( 4→1)-α-L-raminopiranosil]- (6→1)-α-L-apiofuranosídeo. O uso de FIA-ESI-ITMS possibilitou a identificação de glicerolipídeos, enquanto o emprego de HPLC-ESI-IT-MS permitiu...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work we studied the chemical composition and pharmacological activities of the leaves of Alchornea glandulosa and A. triplinervia (Euphorbiaceae), as well as aerial parts of Indigofera truxillensis and I. suffruticosa (Fabaceae), used in Brazilian folk medicine against gastric problems. In the chloroform extracts of the Alchornea species we identified stigmasterol, campesterol, sitosterol, lupeol, friedelan-3-ol, friedelan-3-one and pterogynidine. The study of the methanolic extracts of the Alchornea species afforded gallic acid, methyl gallate, brevifolin carboxylic acid, amentoflavone, isocorilagin, miricetin 3-O-α-L-rhamnopyranoside, quercetin and four glycosilated derivatives. Analyses by FIA-ESI-IT-MS helped to detect the presence of galloylquinic acid derivatives, ellagitannins and proanthodicyanidins in A. triplinervia. The chloroform extract of both Indigofera species led to the identification of indigo (indigotin) and indirubin. The methanolic extract of I. truxillensis gave indigo, indirubin, indican, pinitol, sitosterol-3-O-β-D-glucopyranoside and five glycosilated kaempferol derivatives, among them the new substance kaempferol 3-O-[β-D-apiofuranosyl-(1→2)-α-L- arabinopyranoside]-7-O-α- L-rhamnopyranoside. The methanolic extract of I. suffruticosa contained the same substances described for I. truxillensis, except for kaempferol derivatives, besides gallic acid, allantoin and four quercetin derivatives, besides the new substances 6'-methoxy-2,5,6- trihydroxiisoindirubin, indigotin-3-O-β-D-glucopyranoside, dioxindol-3-O-β-D-glucopyranoside and quercetin-3-O-[α- L-rhamnopyranosyl-(1→4)-[β-D-apiofuranosyl-(1→6)]-β-D-glucoyranoside. The use of FIAESI- IT-MS led the identification of glicerolipids, whereas the use of HPLC-ESI-IT-MS allowed to establish the chemical fingerprint of these species. The Alchornea species presented ...(Complete abstract click electronic access below) / Doutor

Philosophiae Doctor - PhD / South Africa (SA) is home to one of the six floral kingdoms of the world, and hosts a very diverse flora comprising an astonishing ~30,000 species. Herbal medicines play an important role in many of the diverse cultures of this country. Yet, agricultural production systems for most of these species are missing, and medicinal plants are usually collected in the wild. The endemic medicinal plants of SA produce a wide range of rare medicinally active compounds, which could be developed into drugs. Knowledge on the genes involved in the biosynthesis of these compounds could not only promote establishment of plant production systems, but also their biotechnological exploitation. Transcriptomics has been revolutionized by Next Generation Sequencing technologies, which can cost-efficiently provide a lot of information on plant genes and biosynthetic pathways. This thesis focuses on the establishment of methodologies for high-throughput plant transcriptome research, including: 1) harvesting plant material suitable for high-quality RNA analysis from distant locations, 2) high-throughput, and inexpensive biochemical sample screening, 3) extraction of high-quality RNA from recalcitrant, polysaccharide- and polyphenol rich plant material, and 4) biocomputational analysis of Illumina sequencing data, including quality control and pre-processing of data, de novo assembly of reads, protein prediction and functional transcriptome annotation. Rooibos (Aspalathus linearis) was chosen as the pilot plant, because it is one of the few indigenous SA medicinal plants that has been successfully cultivated as a commercial crop. It produces a wide range of phenolic compounds with health promoting properties (e.g. aspalathin and a phenylpropenoic acid glucoside with scientifically verified antidiabetic and cardioprotective effects). In the course of this study, seven rooibos transcriptomes were produced, assembled and functionally annotated, providing a first extensive dataset for identification of genes associated with economically important traits such as medicinal compound production, rooibos growth type characteristics and stress resistance.

Hepatocellular carcinoma (HCC), the major form of primary liver cancer, is a common cause of cancer-related death worldwide. Signal transducer and activator of transcription 3 (STAT3) plays a pivotal role in the pathogenesis of HCC. Inhibition of STAT3 signaling has been proposed as a promising strategy for treating HCC. Due to the limitations of conventional therapeutics, increasing attention has been paid to complementary and alternative medicines (CAM) including traditional Chinese medicine (TCM) for the management of HCC. Antrodia camphorata (AC), a medicinal mushroom, is historically used for treating HCC. Pharmacological data showed that extracts and constituents of AC are able to inhibit STAT3 activation. Natural AC is scarce, cultured AC mycelia are becoming alternatives. AC mycelia have been demonstrated to possess anti-HCC properties. We hypothesize that inhibition of the STAT3 signaling pathway contributes to the anti-HCC mechanisms of AC mycelia. To test our hypothesis, we evaluated the safety and investigated the anti-HCC effects of the ethyl acetate fraction of an ethanolic extract of AC mycelia (EEAC); and we further explored the involvement of STAT3 signaling in EEAC's anti-HCC effects. Acute and repeated dose 28-day oral toxicity studies showed that EEAC had no toxicity in rats. The maximum tolerable dose for acute oral toxicity and the no-observed-adverse effects level for repeated dose 28-day oral toxicity of EEAC were higher than 5,000 mg/kg body weight and 1,000 mg/kg body weight, respectively, in rats. In cultured cells, EEAC is less toxic in normal liver-derived cells than in HCC cells. In HepG2 and SMMC-7721 cells, EEAC reduced viability, induced apoptosis, and retarded migration and invasion. In SMMC-7721 cell-bearing mice, EEAC significantly suppressed tumor growth. EEAC inhibited cell proliferation, induced apoptosis and suppressed angiogenesis in tumors. Mechanistic studies showed that EEAC downregulated protein levels of phosphorylated and total STAT3 and JAK2 (an upstream kinase of STAT3) in HCC cells and tumors. In cultured HCC cells, EEAC lowered the protein level of nuclear STAT3, decreased the transcriptional activity of STAT3, and downregulated protein levels of STAT3 targeted molecules. Over-activation of STAT3 in HCC cells diminished the cytotoxic effects of EEAC. STAT3 can be activated by receptor tyrosine kinases (RTKs). Phospho-RTK array assays showed that EEAC significantly inhibited the tyrosine phosphorylation of platelet-derived growth factor receptor-beta (PDGFR-β) in HepG2 cells. EEAC dose-dependently lowered mRNA levels of PDGF BB (a ligand of PDGFR-β) and protein levels of p-PDGFR-β and PDGFR-β in HCC cells. Activating PDGFR-β enhanced STAT3 activation, and inhibiting PDGFR-β blocked STAT3 activation in HCC cells. EEAC reversed PDGF BB induced STAT3 activation in HCC cells. Our data indicate that EEAC exerts anti-HCC effects, and inhibition of PDGFR-β/STAT3 signaling is, at least in part, responsible for these effects. In summary, we have demonstrated that EEAC exerts anti-HCC effects without significant toxicity in vitro and in vivo. We have also demonstrated that inhibition of PDGFR-β/STAT3 signaling contributes to the anti-HCC mechanisms of EEAC. Our findings provide a pharmacological basis for the development of EEAC as a modern anti-HCC agent and for the traditional use of AC in treating HCC. In addition, our data suggest that the PDGFR-β/STAT3 pathway plays a pathogenic role and presents a novel therapeutic target in HCC.

For centuries Aloe vera has been exploited for several verified and unverified medicinal uses such as wound healing, treatment of gastrointestinal ulcers and for its many biological effects including anti-microbial, laxative, anti-inflammatory and immunostimulatory activities. Studies have generally focused on its effects in vitro and in adults. When nursing mothers use Aloe vera extracts, their suckling infants are at risk of indirect exposure to Aloe vera via breast feeding or directly as dietary/health supplements. The gastrointestinal tract (GIT) of the neonate is sensitive to dietary manipulations during the suckling period with long lasting effects that can be irreversible. Thus babies may be at risk if administered Aloe vera extracts directly as dietary supplements or indirectly via breast milk. The main objectives of this study were to evaluate the effects of orally administered aqueous and alcohol extracts of Aloe vera on growth performance, the morphometry and morphology of the gastrointestinal tract and accessory organs, and liver function of suckling rats. Suckling Sprague-Dawley rats (77), males (n=38) and females (n=39) of 6 days old were randomly assigned to one of five treatment groups and given once daily by oral gavage a suspension of lyophilized crude alcohol or aqueous extracts of Aloe vera suspended in distilled water. Group I (control) was gavaged with distilled water (vehicle). Group II received a low dose of the aqueous extract (AqL) at 50mg. kg-1; Group III received a high dose of the aqueous extract (AqH) at 500mg. kg-1; Group IV received a low dose of the alcohol extract (AlcL) at 50mg. kg-1 whilst Group V received a high dose of the alcohol extract (AlcH) at 500mg. kg-1. The extracts and distilled water were 2 administered at a volume of 10ml.kg-1. The pups remained with their dams for the duration of the study and after 8 days on the treatments, the pups were humanely killed to harvest their tissues for measurements and physiological analysis. All data were expressed as mean ± SD and analyzed by one way ANOVA, the values were considered statistically significant when p < 0.05 and then a Bonferroni Post hoc test was applied. The suckling rats fed respectively with high doses of AlcH and AqH had a significantly higher body mass gain than the other groups (p < 0.05, one way ANOVA). Linear growth as measured by tibial length was significantly increased in the AqH group compared to the other groups. There was no significant difference in the mass and relative density of the tibia bones of the rats from the different treatment groups. The differences in growth could not be attributed to circulating concentrations of the somatotrophic hormone, Insulin-like growth factor-1 (IGF-1) which was not significantly different between the groups. The treatments did not result in any significant differences in lengths, and mass of the small and large intestine, however the caecum was significantly enlarged (hypertrophy of muscularis, submucosa and mucosa) in the rats that received the Aloe vera extracts. Although, there was no significant difference in the mass of the rats’ livers, the lipid and glycogen content were significantly higher (p < 0.001) for the AqH group compared to the other groups. Histologically, the hepatocytes showed enlarged nuclei, granular cytoplasm and dilated sinusoids for AqH and AlcH as compared to the control group. An indirect assessment of liver function by measurement of blood concentrations of alkaline phosphatase (ALP) and alanine amino transaminase (ALT) did not reveal a significant difference between the groups. The non fasting concentration of metabolic substrates (glucose and triglycerides) was also not significantly different between the groups. The pups given high doses of the extracts had a significantly greater (p < 0.05) thymus mass (hyperplastic) than the other groups. The short term administration of Aloe vera extracts has shown a growth promoting effect, enhanced hepatic storage of metabolic substrates and hypertrophy of the caecum and thymus of neonatal rats. These effects need to be explored further to enhance animal production and health.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2014. / Heavy metal pollution is an increasing phenomenon and contamination of these heavy metals has detrimental effects on the environment and humans. The concentrations of metals in the soil, leaves, stem bark and flowers of Moringa ovalifolia sampled from Okahandja, Okaukuejo, Halali and Tsumeb in Namibia were investigated. Acid digestion of all samples was performed utilising the microwave technique. Determination of elements from the extracts were analysed by inductively coupled plasma - optical emission spectroscopy (ICP-OES). No lethal amounts of heavy metals were found in the soil, leaves, stem bark and flowers of Moringa ovalifolia. The results from Moringa ovalifolia was compared to spinach from another similar study. On average, Moringa leaves contained more or less similar amounts of Zn (29.4 mg kg-1) and Cr (13.2 mg kg-1) but higher higher amounts of Fe (263.8 mg kg-1) concentrations than spinach, with values of Zn (30.0 mg kg-1), Cr (20.0 mg kg-1) and Fe (190 mg kg-1) from a previous study. In this study, selected statistical methods such as correlation analysis and principal component analysis were used to identify the origin of these metals in the soil, leaves and stem bark collected from the Moringa farm, national parks and the road side in Namibia. From the correlation analysis, it was found that Co, Mg, Cr and Mg pairs were highly significant to each other. The principal component analysis revealed that heavy metals gave 53.41% of the total variance in factor 1. Sources of Mg and Ni could be from vehicle emissions. Factor 2 revealed As, Co, Al, and Si contributing to a total variance of 25.15% Co suggesting that the metals present could be as a result of geologic sources. This iii study proves that statistical analysis may provide a scientific foundation for the observation of heavy metal accumulation in samples. Pressurised hot water extraction (PHWE) was used for the extraction of bioactive compounds from the leaves and stem bark of Moringa ovalifolia and Moringa oleifera samples. The aim of the study was to assess the effect of temperature and extraction process of the Moringa extracts on Staphylococcus aureus (S. areus), Enterococcus faecalis (E. faecelis) and Pseudomonas aeruginosa (P. aeruginosa). The antibacterial activities of the extracts at varying temperatures were evaluated using the disk diffusion method where the zones of inhibition were recorded. ANOVA, which was calculated at a significance level of 0.05, was used to analyse the data. Antimicrobial activity of the stem bark extracts and leaf extracts from different sites extracted at 25˚C and 80˚C showed significant difference. As temperature increased, a decrease in inhibition was observed for stem bark extracts from different sites tested again S. areus, E. faecelis and P. aeruginosa. When the PHWE stem bark extracts collected in Tsumeb, were compared with ethanol and cold water extractions, the PHWE had more activity than other two methods. This proves that PHWE may be used as a novel extraction to get essential compounds from indigenous plant materials.