University of Macau / Institute of Chinese Medical Sciences

Ethnobotanical and dietary questionnaires were used to assess the utilization of plants to treat the signs and symptoms of anemia by women in La Chapelle, Haiti. The usual diet of respondents was found to be low to intermediate in iron bioavailability. The ethnobotanical questionnaire showed that most respondents (82%) used plant-based home remedies to treat anemia Amaranthus dubius, Citrus aurantium, Corchorus olitorius, Moringa oleifera, Phaseolus vulgaris and Portulaca oleracea used in the diet and as remedies for anemia were analyzed. Amaranthus dubius was found to have the higher in availability by in-vitro dialysis, 30%. The intra species variation in iron availability was influenced by storage and cooking times. The interspecies variation in iron availability was explained by the acidity of the plant species' cooked homogenate (r = 0.4168, p = 0.007).

<p>The incidence of cardiovascular diseases, including hypertension, is on the increase worldwide. Medicinal plants played an important role in the treatment of hypertension for centuries. Very few scientific studies have, however, been done to validate the use of these phytotherapies. O africana is on of the many phytotherapies that has been use indigenously for years to treat hypertension. The objectives of this study were to determine the most effective does of O africana aqueous extract which will reduce blood pressure / to determine whether chronic administration of O africana can be used to prevent and treat hypertension / to determine whether O africana exert its effects by modulation of the renin-angiotensin system.</p>

<p>Basella alba (BA) and Hibiscus macranthus (HM) are used by traditional healers in Cameroon to treat male sexual fertility problems. Previous studies showed that in vivo administration of the leaf extracts of both plants caused a significant increase in rat seminal vesicle weight and spermatozoa numbers was accompanied by a significant increase in serum testosterone. The aim of this study was to establish the effects of BA and HM extracts on Sertoli cell functions. TM4 cell line was used in this study as it exhibited properties similar to the Sertoli cells (Mather, 1982). Sertoli cell play a key role in spermatogenesis by regulating and supporting germ cell development. Therefore, any alterations in Sertoli cell physiology or structure may lead to impaired spermatogenesis, germ cell loss and male infertility. Developing germ cells in the seminiferous tubule require a constant supply of lactate and pyruvate (Jutte et al, 1981 / 1982) and toxicant induced alterations in these nutrients have been shown to induce germ cell necrosis (Monsees et al., 2000). TM4 Sertoli cells were cultured in DMEM/Ham F-12 (M) for one day and exposed to<br /> 0.01, 0.1, 1, 10, 100 &mu / g/ml of BA and HM extracts, respectively, for four further days. The extracts were dissolved in 0.5 % DMSO in M, while 0.5 % and 2% DMSO in M were used as negative or positive controls, respectively, and 100mM ethanol as positive control where indicated. Results obtained from the Sertoli cells exposed to BA extracts, showed that the plant extract had no significant effect on the cell viability but induced a significant concentration-dependent increase in lactate (19-67%) and pyruvate levels (39-102%) and a concentration-dependent decrease in the protein content (9-42%). The H&amp / E histological study confirmed that the BA extract had no cytotoxic effect, as there were no changes in the morphology of the cell. Likewise, apoptotic study using DAPI showed no alteration in the nucleus when compared to the negative control. The HM plant extract significantly enhanced mitochondrial dehydrogenase activity (7fold) in the Sertoli cells but caused only slight alterations in the lactate and pyruvate levels. There was no effect seen in the protein content of the Sertoli cells. H&amp / E and DAPI staining revealed that there were neither changes in the morphology of the cells nor any alteration regarding the mitotic and apoptotic indices. Thus, the HM extract did not have a cytotoxic effect on the cells. This study demonstrated that the Basella alba methanol extract may enhance spermatogenesis as it stimulated the source of energy required for the development of germ cells without exerting a cytotoxic effect. The Hibiscus macranthus extract stimulated mitochondrial dehydrogenase activities and may thus trigger changes in Sertoli cell physiology. In summary, both plant extracts enhanced certain Sertoli cell<br /> functions and thus might explain the positive in vivo effects of the combined plant extracts on rat spermatogenesis observed by Moundipa et al. (1999).</p>

Submitted in fulfillment for the Degree of Master of Technology (Biotechnology) in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, 2009. / Information regarding the nutritional value of wild food plants in Africa and current information varies from source to source. Prior to commercialization of wild foods the nutritional, ethnobotanical, medical, chemical, anthropological and toxicity requires investigation. Plants from the Amaranthaceae family were chosen because the family is characterized by several species which are used by indigenous communities as a source of nutrition in different plants of the world. The focus of this study was to investigate the nutritional and biological activities of three plants from the Amaranthaceae family viz. Achyranthes aspera, Alternanthera sessilis and Guilleminea densa that are considered famine plants. This study aimed to determine the nutritional value (proximate, minerals and vitamins), biological activity, toxicity and potential of a tissue culture system for three species from the family Amaranthaceae. Nutritional analysis comprised of determining moisture, ash, protein, fat, carbohydrate, dietary fibre and energy. Mineral analysis of calcium, copper, iron, magnesium, manganese, phosphorus, sodium and zinc was performed by microwave digestion and then analyzed by ICP Spectrophotometry. Vitamin A, Vitamin B1, Vitamin B2, Vitamin B3 and Vitamin C were also analyzed. For biological and safety analyses aqueous and methanolic extracts were prepared. Anti-oxidative and anti-inflammatory properties of the extracts were tested; antimicrobial activity was tested by evaluating the bactericidal, fungal effect and minimum inhibitory concentration on selected bacteria and fungi using the agar disk diffusion method. Anti mosquito potential was determined by setting up repellency, larvacidal assay and insecticidal assay. The safety and toxicity analysis was carried out by measuring cytotoxicity, toxicity and mutagenicity. The potential of an in vitro tissue culture system of A. aspera, A. sessilis and G. densa was determined using micropropagation. A. aspera indicated significant amounts moisture, ash, dietary fibre, protein, vitamin B1, vitamin B2, magnesium and manganese. Plant extracts of A. aspera had antibacterial activity against the Gram negative bacteria Esherichia coli, Pseudomas aeroginosa and Salmonella typhi; Gram positive bacteria Staphylococcus epidermis and Staphylococcus aureus. The methanolic extract had antifungal activity against Sacchromyces cerevisiae and exhibited significant free radical scavenging activity as well as 85% repellency against Anopheles arabiensis. The aqueous extract stimulated the growth of the K562 (Chronic Myclogenous Leukaemia) cell line and the plant extracts showed no mutagenicity or toxicity. A. sessilis indicated significant levels of ash, dietary fibre, protein, energy, vitamin A, vitamin B1, vitamin B2, vitamin B3, iron, magnesium and manganese present. Plant extracts of A. sessilis had antibacterial activity against Gram negative bacteria P. aeroginosa and Gram positive bacteria S. epidermis. The plant also showed antifungal activity against the yeasts S. cerevisiae and Candida albicans. The methanolic plant extract showed excellent antioxidant activity. The aqueous plant extract stimulated the growth of the K562 cell line and the plant extracts possessed no mutagenicity or toxicity. This plant grew well in a tissue culture system where it was propagated from callus to a fully grown plant able to survive in environmental conditions. G. densa has ash and dietary fibre, vitamin B2, vitamin B3 and iron. The plant extracts had antibacterial activity against Gram negative bacteria E. coli, P. aeroginosa and Klebsiella. oxytoca; Gram positive bacteria Baccilus stereathermophilus and S. aureus. The plant also has antifungal activity against C. albicans and significant repellency activity against A. arabiensis where it showed 100% repellency. This plant was not found to be mutagenic or toxic. The results obtained from this study show promising potential for the plants to be exploited as famine food plants. The nutritional value, biological activity and ability to micropropagate A. aspera, A. sessilis and G. densa indicates a good potential for purposes of harnessing biotechnological products.

Submitted in fulfillment of the requirements for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2009. / Dichrostachys cinerea, Carpobrotus dimidiatus, Capparis tomentosa and Leonotis leonurus are all plants that are indigenous to South Africa. These plants are used in traditional medicine to treat various ailments. However, there is little or no scientific data to justify these traditional uses. Furthermore, it is difficult to reconcile traditional knowledge with scientific evidence because of the overwhelming targeting of signal-responsive systems by plant defensive compounds, multiple sites of action and the connectedness of the signaling pathways, which provide many cures and have pleiotropic effects. In order to evaluate the action spectrum of these plants, and validate its widespread use, this research evaluated the antibacterial, antioxidant, anti-inflammatory, anti-mosquito and immunomodulatory properties of these plants. Antimicrobial activity of the extract was determined by evaluating the bactericidal and fungicidal action using the agar disc diffusion assay. Anti-oxidative properties of the extracts were tested using the DPPH photometric assay. Anti-inflammatory properties were carried out using the 5-lipoxygenase assay. The larvicidal, repellency and insecticidal assay was determined against A.arabiensis. The safe use of these plant extracts was determined by evaluating toxicity, a brine shrimp lethality assay and an in vitro cell culture system using human myelogenous leukemia cell line. Potential carcinogenic activity was evaluated using the Ames Salmonella Mutagenecity assay. The immunomodulatory activity of the extracts on human peripheral blood mononuclear cells 6 was evaluated on freshly harvested lymphocytes using the MTT assay. Cytokine response was evaluated by measuring the secretion of interferon-gamma and interleukin-10. Elucidation of the B cells, T cells, activated T cells, CD 4+, CD 8+ and NK cells was performed by flow cytometry. The extracts showed anti-microbial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Salmonella typhimurium, Serratia marcescens, Bacillus cereus and Tricoderm sp. The highest activity was shown by methanolic and aqueous extracts of L. leonurus leaves followed by methanolic and aqueous extracts of D. cinerea. Extracts of C. tomentosa and D.cinerea demonstrated a higher degree of free radical scavenging than rutin, which was used as a standard indicating that these plants have strong antioxidant properties. None of the plants showed significant anti-inflammatory activity when compared to NDGA. In the anti-mosquito assays, the extracts showed strong repellency and insecticidal activity. L. leonurus extracts demonstrated the highest insecticidal and repellency activity against the mosquito, and was also found to cause ‗knockdown‘ and mortality. The extracts display no toxicity, cytotoxicity and mutagenicity. The immunological studies for immune modulation showed that the methanol extracts of these plants induce a Th1- predominant immune response because they significantly suppressed the secretion of IL-10 and augment IFN-γ production, which are hallmarks used to indicate a stimulation of the innate immune response. This study also provides new information, with respect to the potential use of these plants in producing a mosquito repellent and an immunostimulant.

Eucomis (Family Hyacinthaceae) are deciduous geophytes with long, narrow leaves and erect, densely packed flower spikes. The bulbs are greatly valued in traditional medicine for the treatment a variety of ailments, and are thus heavily harvested for trade in South Africa's "muthi" markets. Eucomis species propagate relatively slowly from offsets and seed, and this, together with their over-utilization ethnopharmacologically, has led to their threatened status. This investigation focussed mainly on the study of the anti-inflammatory activity of plant extracts prepared from the leaves, bulbs and roots, and the development of suitable tissue culture protocols for the bulk propagation of the species under study. Common underlying symptoms in the majority of ailments treated with traditional remedies prepared from Eucomis species are pain and inflammation. Prostaglandins are the primary mediators of the body's response to pain and inflammation, and are formed from essential fatty acids found in cell membranes. This reaction is catalysed by cyclooxygenase, a membrane-associated enzyme occurring in two isoforms, COX-1 and COX-2. Non-steroidal anti-inflammatory drugs (NSAIDs) act by inhibiting the activity of COX. The use of commercially available COX-1 inhibitors is associated with side-effects, including gastric and renal damage. Selective COX-2 inhibitors do not have these undesired effects, and are thus potentially very valuable to the pharmaceutical industry. The relative inhibitory effects of different extracts of Eucomis species on the activities of purified cyclooxygenase enzyme preparations (COX-1 in sheep seminal vesicles, COX-2 in sheep placenta) were assessed. The COX-1 assay was used to screen extracts from 10 species of Eucomis and one hybrid species at a concentration of 250 μg mℓ ¯¹ in the assay. High levels of anti-inflammatory activity were exhibited by the ethanolic extracts prepared from the dried leaves, bulbs and roots. Aqueous extracts (screened at 500 μgmℓ ¯¹) showed much lower levels of activity. In general, the highest levels of anti-inflammatory activity were observed for the ethanol bulb and root extracts. Comparison of the activity of the bulb extracts from bulbs harvested in summer and winter revealed very little difference in COX-1 inhibitory activity. Eucomis extracts were separated using thin layer chromatography. The plates were developed in a solvent system of benzene : 1,4-dioxan : acetic acid, 90:25:4 and stained with anisaldehyde-sulphuric acid. The TLC fingerprints prepared from these extracts showed different chemical profiles for the leaf, bulb and root extracts, but many similarities between the different species. The position of the active R[f] fractions was determined and correlated with the TLC-fingerprints. The most widely utilized species medicinally, E. autumnalis subspecies autumnalis, was chosen for further investigation. The fluctuation of anti-inflammatory activity with season and physiological age was determined. Young plants were found to have high levels of COX-1 inhibitory activity, particularly in the leaves. As the plant matured, higher levels of activity were associated with the bulb and root extracts. The antiinflammatory activity of the leaf, bulb and root extracts varied slightly throughout the year, with the highest levels detected towards the end of the growing season, shortly before the onset of dormancy. This study of E. autumnalis autumnalis was extended to investigate the effects of environmental conditions on the levels of COX-1 inhibitory activity. The extent to which high temperature and light intensity, fertilization of the plants in summer with Kelpak preparations, and cold storage of the dry bulbs during winter, affected the levels of active compounds accumulated, was determined. Kelpak application decreased the anti-inflammatory activity of the leaf, bulb and root extracts, while high temperature / high light intensity had no significant effect on the COX-1 inhibitory activity of the leaf or bulb extracts. The root extract did show a significant increase in anti-inflammatory activity. Bulbs that were removed from the soil and stored at 10°C exhibited significantly higher COX-1 inhibitory activity than the control bulbs maintained in the soil. Higher COX-1 inhibition was observed in the leaf extracts from these plants when harvested half-way through the growing season. No significant difference was observed at this stage between the bulb and root extracts from the different treatments. Bioassay-guided fractionation (using the COX-1 assay) was used to isolate the active principle(s) in the bulb extract. The bulb material was subjected to serial extraction using a Soxhlet apparatus. The ethyl acetate fraction showed the highest levels of COX-1 inhibition, and this was further fractionated using a Sephadex LH-20 column and a solvent system of cyclohexane : dichloromethane : methanol (7:4:1). The most active fraction from this separation was then purified using semi-preparative TLC and HPLC. The primary compound eluting in this fraction had an IC₅₀ value of 14.4 μgmℓ ¯¹ in the COX-1 assay, and 30.5 μgmℓ ¯¹ in the COX-2 assay. This compound was tentatively characterized as a phenol ring attached to a conjugated hydrocarbon chain (with a molecular weight of 390), and was a potent COX-1 inhibitor. The COX-2 / COX-1 inhibitory ratio was calculated to be 2.1. A second, highly active compound, with IC₅₀ values of 25.7 μgmℓ ¯¹ and 21.8 μgmℓ ¯¹ in the COX-1 and COX-2 assays respectively, crystalized from one of the Sephadex LH-20 column fractions. This compound was identified as a spirostane-type triterpenoid, eucosterol, previously isolated from Eucomis species but not specifically linked to the pharmacological activity of the extracts. This compound showed COX-2 / COX-1 inhibitory ratio of 0.8, indicating that it was a selective COX-2 inhibitor. Two further compounds were identified from this extract, after crystallization from different fractions obtained from Sephadex LH-20 chromatography. These were both homoisoflavanones, 5,7-dihydroxy-6-methoxy-3-(4-methoxy benzyl)-chroman-4-one, and 5,7-dihydroxy-3-(4-methoxy benzyl)-chroman-4-one [eucomin], the latter having been isolated previously. The first compound exhibited very low levels of both COX-1 and COX-2 inhibition, and the second compound (eucomin) exhibited high COX-1, but low COX-2 inhibitory activity. The in vitro propagation of the genus Eucomis was undertaken primarily to provide a source of material for experimentation, and also to optimize this technique for the bulk production of plants for commercial and conservation purposes. Multiple shoot production was initiated from leaf explants, in all species studied. A Murashige and Skoog (MS) medium, supplemented with 100 mg ℓ ¯¹ myo-inositol, 20 g ℓ ¯¹ sucrose, and solidified with 2 g ℓ ¯¹ Gelrite® was used. The optimal hormone combination for shoot initiation in the majority of species was determined to be 1 mg ℓ ¯¹ NAA and 1 mg ℓ ¯¹ BA. Optimal root initiation was demonstrated on media supplemented with 1 mg ℓ ¯¹ IAA, IBA or NAA, depending on species. A continuous culture system using this protocol produced 25-30 plantlets per culture bottle, with 10-25 specimens per bottle available for acclimatization. To maximize plantlet survival, different support media used during the acclimatization process were necessary. Certain species responded best on a vermiculite medium, while perlite (which holds less water) was necessary for the optimal survival rate of other species. Acclimatized plantlets were repotted in a sand : soil mix (1:1). Further experimental work aimed to determine the factors affecting the accumulation of anti-inflammatory compounds in in vitro plantlets. Extracts prepared from in vitro plantlets showed high levels of COX-1 and COX-2 inhibitory activity, with a C0X-2/C0X-1 ratio of 1.1. High levels of sucrose (40 g ℓ ¯¹) significantly increased the number of shoots initiated, but had no effect on the anti-inflammatory activity. Low levels of sucrose (10 g ℓ ¯¹) led to a significant decrease in COX-1 inhibition. Changing the levels of nitrogen in the medium (but not the ratio of nitrate to ammonium ions) had no significant effect on the COX-1 inhibitory activity of the extracts. Callus was initiated from leaf explants and experiments were conducted to maximize callus proliferation. Optimal callus growth occurred on an MS medium supplemented with 100 mg ℓ ¯¹ myo-inositol, 30 g ℓ ¯¹ sucrose, 2 g ℓ ¯¹ Gelrite® , and a hormone combination of 10 mg ℓ ¯¹ 2,4-D and 2 mg ℓ ¯¹ kinetin. Callus cultures maintained in the dark grew best. Callus extracts tested in the COX assays (250 μgmℓ ¯¹) showed a higher level of COX-2 inhibition (69%) than COX-1 inhibition (46%). Lastly, the conclusive identification of the species under study was attempted, using DNA fingerprinting. Protocols were developed for the extraction of DNA from the leaves of Eucomis plants, and the optimization of the AP-PCR technique. Random sequence (10-base) oligonucleotide primers were screened, each primer used singly. Primers were selected on the basis that more than five distinct bands were detected. Differences were detected in the amplification products visualized using nondenaturing agarose gel electrophoresis stained with ethidium bromide. This work provides the basis for further studies into the phylogenetic relationships between the various species (and hybrids) of Eucomis. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.

The genus Helichrysum (Asteraceae) consists of approximately 500 species worldwide, with 245 indigenous to South Africa. As a result of the large number of species, the chemistry and biological activity of several species have not yet been investigated. The aim of this project was to investigate the phytochemistry of three species and propose a synthetic route to one of the antibacterial compounds isolated. An extensive literature review regarding the widespread traditional uses, biological activity and phytochemistry of the South African Helichrysum species is provided. From Helichrysum splendidum, a plant used traditionally to treat rheumatism, two monomeric guaianolides and a dimeric guaianolide, helisplendidilactone, were isolated. The stereochemistry of these known compounds was confirmed and the NMR assignments for certain peaks of helisplendidilactone were corrected. An X-ray structure for helisplendidilactone was obtained for the first time. The phytochemistry of Helichrysum montanum was investigated for the first time and new diastereoisomers of known guaianolides were isolated. The phytochemistry of H. splendidum and H. montanum is remarkably similar and supports their morphological classification in the same taxonomic group. The chloroform:methanol extract of H. montanum yielded a new dimeric guaianolide, 13’-epihelisplendidilactone, which is related to helisplendidilactone, as well as three monomeric guaianolides (of which one is a new diastereomer of a known compound). The extract also yielded spathulenol (a sesquiterpene), umbelliferone (a coumarin) and 4’,5,7-trihydroxy-3,3’,8-trimethoxyflavone (a flavonoid). Thirty-five Helichrysum species were screened for antimicrobial activity against six microorganisms and a preliminary cytotoxic assay, which included the use of “normal” and cancer cell lines, was performed. H. excisum was selected for further study based on the fact that it exhibited promising antimicrobial activity and relative low toxicity. Furthermore, with the exception of the essential oil, the phytochemistry of this species has not been investigated. From the aerial parts of H. excisum, five flavonoids, identified as pinocembrin, gnaphaliin, lepidissipyrone, 5-hydroxy-7,8-dimethoxyflavone and isoscutellarein 7-O-b-glucoside were isolated. Four of these flavonoids have an unsubstituted B-ring, a phenomenon often observed in flavonoids isolated from Helichrysum species. The active antimicrobial component of H. excisum has been identified as lepidissipyrone. Owing to the interesting biological activities reported for phloroglucinol a-pyrones and the synthetic challenges associated with these molecules, lepidissipyrone was selected for a synthetic study. Both the flavanone and pyrone moieties present in lepidissipyrone have been successfully synthesised. A successful strategy towards the CH2 linker between the two units has been illustrated. The strategy could be used to synthesise similar phloroglucinol-derived pyrones. / Thesis (Ph.D.) - University of KwaZulu-Natal, Pietermaritzburg, 2008.

The total synthesis of a novel diarylheptanoid isolated from a South African medicinal plant, Siphonochilus aethiopicus, was investigated. S. aethiopicus (Indungulu in Zulu) is the only South African species of the Zingiberaceae plant family and is widely used in traditional medicine. One of the compounds isolated from this plant is a novel diarylheptanoid. Diarylheptanoids constitute a distinct group of natural plant metabolites characterized by two aromatic rings linked by a linear seven-carbon aliphatic chain, with varying functional groups on the aryl and the aliphatic chain. The target molecule for our synthesis contains two highly oxygenated aryl rings linked by an aliphatic chain with two stereogenic centres and a trans-alkene. In this study we present our investigation of different strategies to a viable synthetic method that could provide material to supplement the relatively small quantity of product that can be isolated from the plant extract. The major challenges of this synthesis were to develop procedures for the preparation of the homobenzylic trans-alkene, the stereogenic centres and to attach the electron-rich aromatic rings to the aliphatic chain. In this thesis the following aspects are described: • Various types of olefination reactions (including Wittig, Julia and organometalic-mediated type of olefination reactions) • Various types of alkylation reactions (including Grignard, Friedel-Crafts and organometalic-mediated type of alkylation reactions) • Incorporation of the stereogenic centres (including asymmetric hydroxylation and use of chiral starting materials) The synthesis will not only give a viable synthetic route to the target compound but is also versatile enough to allow the preparation of analogues. / Thesis (Ph.D. (School of Chemistry)) - University of KwaZulu-Natal, Pietermaritzburg, 2008.

This work is an account of the investigations into the chemistry of two Cedrelopsis species from the Ptaeroxylaceae, Cedrelopsis grevei and Cedrelopsis microfoliata and a species from the Mesembryanthemaceae, Khadia alticola, as well as investigations into the synthesis of hydroxylated and prenylated chalcones. Cedrelopsis grevei, commonly called Katrafay, is amongst the many medicinal plants of Madagascar, being used to relieve muscle fatigue when the bark is soaked in hot water. Previous investigations of the wood and stem bark of this plant, have yielded chromones and coumarins and a recent investigation of the stem bark of a specimen collected in the north of Madagascar has yielded two novel limonoids of unusual structure, cedmilinol and cedmiline. The fruit and seed of Cedrelopsis grevei have not been studied previously and a phytochemical investigation of these plant parts was undertaken in this work. The dichloromethane extract of the fruit and seeds yielded, after column chromatography, a dihydrochalcone, uvangoletin, a flavanone, 5,7dimethoxypinocembrin, two simple chalcones, cardamonin and flavokawin Band three prenylated chalcones, 2’-methoxyhelikrausichalcone, cedreprenone and cedrediprenone. Three of these compounds, 2’-methoxyhelikrausichalcone, cedreprenone and cedrediprenone have not been isolated previously. Cedrelopsis microfoliata is another medicinal plant used in Madagascar. The leaves of this plant are used to prepare a decoction for woman to drink after childbirth. This is the first phytochemical investigation of Cedrelopsis microfoliata. The hexane extract of the dried stem bark yielded three compounds after column chromatography, a chalcone, microfolian and two flavanones, microfolione and (+)-agrandol. The dicholoromethane extract of this compound yielded four compounds after column chromatography, three coumarins, cedrecoumarin A, obliquin and microfolicoumarin and a sesquiterpenoid, sesquichamaenol. Four of the compounds isolated from Cedrelopsis microfoliata, microfolidione, microfolione, (+)-agrandol and microfolicoumarin have not been isolated previously. Khadia alticola is one of the species added to "Khadi", a Tswana/South Sotho name for beer brewed traditionally using the fleshy roots of a variety of taxa. Khadia is also reported to be used medicinally by the Manyika people of the Umtali district of Zimbabwe. The phytochemical investigation of the roots of Khadia alticola, which have not been studied previously, was undertaken to determine whether mesembrine type alkaloids were present in this species and thus contributing to the "potency" of the beer brewed traditionally. No mesembrine alkaloids were isolated in this work, however, a common sterol, sitosterol was isolated from the acidic chloroform fraction of the roots of this species and a flavonoid, 3,4',5,7-tetrahydroxyflavan was isolated from the basic chloroform fraction. Two chalcones, 3’,5’-dihydroxychalcone and 2’-hydroxychalcone were synthesised using the Claisen condensation. An isoprenylated acetophenone intermediate and an isoprenylated chalcone were also synthesised. / Thesis (Ph.D.)-University of Natal, Durban, 2001.