University of Macau / Institute of Chinese Medical Sciences

University of Macau / Institute of Chinese Medical Sciences

M.Sc. / The continued use and popularity of plant based traditional medicine necessitates scientific validation of the therapeutic potential of medicinal plants through phytochemical and pharmacological screening as well as the isolation and identification of bioactive compounds. Since the pharmacological effectiveness of medicinal plants is affected by several intrinsic and extrinsic factors, studies on the variations on chemical composition and biological activity are important as well. These provide a scientific rationale for using plants from different regions for the same medicinal purposes and allow traditional healers and consumers to make informed decisions with regard to the collection and use. Rapanea melanophloeos is a popular medicinal plant from the Myrsinaceae family widely distributed in southern Africa. It‟s bark, fruits and rarely the leaves are used traditionally for ailments ranging from stomach disorders, respiratory problems to disorders of the nervous system. Available chemical information reports on the accumulation of benzoquinones as major compounds, as well as some triterpenoid saponins and tannins. In view of the plant‟s wide distribution and medicinal use of different plant parts, this study comparatively evaluated the chemical composition of various crude extracts of the leaves, fruits and bark of plants collected from six localities. This was coupled with antibacterial tests to evaluate the therapeutic potential of different solvent extracts of the leaves, fruits and bark as well as the isolation of bioactive compounds from the fruits. Plants were collected from six different localities between Swaziland and South Africa and sequentially extracted with petroleum ether, ethyl acetate, methanol and water as a series of increasingly polar solvents. Thin layer chromatography (TLC), Gas-Chromatography/Mass spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC) were used to obtain a semi-quantitative chemical composition profile of different extracts. The TLC fingerprints of petroleum ether, ethyl acetate and methanol extracts showed the accumulation of non-polar terpenes, benzoquinones, saponins, tannins and flavonoids in the three plant parts. Slight variations in the chemical composition of the leaves, bark, and fruits were noted. Some components occurred in specific plant parts and others occurred in all three plants. The chemical profile of the leaves and bark were quite comparable in most instances with the fruits showing a generally different profile. This confirms previous literature reports on the comparability of leaves and the bark accounting for interchangeable use in traditional medicine.

Ph.D. (Chemistry) / The following study was conducted to explore the in vitro antimicrobial and synergistic properties of the two medicinal plants (Elephantorrhiza elephantina, Fabaceae and Pentanisia prunelloides, Rubiaceae), which are widely used in southern Africa. These two plant species are used to remedy various ailments including diarrhoea, dysentery, inflammation, fever, rheumatism, heartburn, tuberculosis, haemorrhoids, skin diseases, perforated peptic ulcers and sore joints. The cytotoxicity of the aqueous and methanol extracts and fractions of both species was studied using the brine shrimp lethality tests for the first time. The results demonstrated that the lethality (LC₅₀) for crude extracts for both plants ranged between 1.8 and 18 μg/mL which was relatively greater than the fractions of the extracts. This suggested that crude extracts were more potent than their respective fractions which further implied that the different fractions of phytochemicals in these plant species work jointly (In synergy) to exert their therapeutic efficacy. The antimicrobial activity of methanol and aqueous extracts of rhizomes was investigated by means of a checkerboard micro-dilution technique in a bid to validate possible synergistic interactions between the two plants...

Ph.D. (Chemistry) / The Forensic Chemistry Laboratory of Johannesburg (FCL JHB) is tasked with the chemical analysis of a variety of samples to assist in determining the cause of death where unnatural cause is suspected. Some of the samples submitted to the laboratory have a herbal or muti connotation, but a large portion of these cases turn out to have no herbal components present as only pharmaceutical or agricultural products are detected in these samples. This study combined, for the first time, forensic investigation, chemistry and botany to create a unique platform needed for the identification of poisonous plants and their components in forensic exhibits and viscera. The research was focussed on the poisonous plants previously detected at the laboratory, as well as the requests received for the analysis of muti/toxic plant components. The selection of plants included Nicotiana glauca, Datura stramonium / Datura ferox, Callilepis laureola, Boophone disticha / Ammocharis coranica, Abrus precatorius, Ricinus communis, Nerium oleander / Thevetia peruviana and Bowiea volubilis. All these species are known to have caused fatalities, hence their choice. Nicotiana glauca has been implicated in the deaths of at least 15 people since 2001. It was previously detected by GC-MS (EI) in plant exhibits, but could not be detected in a viscera matrix. A selective extraction method for alkaloids was used to extract botanical and viscera samples. Anabasine was successfully detected on the HPLC-MS (EI) system but this detection technique was not considered sensitive enough. A very sensitive HPLC-MS method was developed on the ZMD detector by using electrospray technology. This method outperformed both electron impact detectors (GC and HPLC) and could detect 1ng/ml anabasine with relative ease in full scan mode. Datura stramonium and D. ferox have not been previously positively linked to any human poisoning or death due to exposure to botanically derived products at the FCL JHB. Atropine and scopolamine were successfully ionised in ESI positive mode and could be detected at 10 pg/ml and 100 pg/ml level respectively. The identities of the compounds were confirmed by characteristic ISCID fragmentation patterns. The developed method was successfully applied to a suspected heart attack case. The results proved conclusively that the deceased was given D. ferox seeds as part of his meal and an overdose of atropine and scopolamine contributed to his death...

M.Sc. / A biosystematic study of the genus Sutherlandia (L.) R. Br., a poorly studied genus with confusing geographical variants, is presented. The species of Sutherlandia are all endemic to southern Africa. The species are very closely related and problems regarding their taxonomy are discussed. A few morphological characters that are useful in distinguishing amongst species are illustrated and discussed in detail. Morphological data are used to investigate infrageneric relationships in a phenetic analysis of 51 geographically separated populations. Sutherlandia has traditional medicinal uses, mainly as an anti-cancer treatment for internal cancers and as a general tonic. A survey of chemical compounds was done and the results are illustrated and presented in tables. The nature of this study did not allow detailed medical investigations, but the medicinal value of Sutherlandia and the compounds detected are highlighted. It is suggested that the anti-cancer activity can mainly be ascribed to the high levels of canavanine, a non-protein amino acid, in the leaves of the plant. Canavanine, an arginine analogue, is known for its antitumourigenic properties. The value of the plant as a bitter tonic is probably related to the presence of several triterpenoids, some of which may well also have other beneficial effects. Enzyme electrophoresis was done to explore genetic relationships amongst the numerous regional forms of Sutherlandia. A study of 19 populations showed that they are all closely related and that a more conservative treatment of the taxa is called for. As a result the number of taxa is reduced. A complete taxonomic revision of the genus is presented. The number of species is reduced from six to two, namely S. frutescens and S. tomentosa. The former is divided into three subspecies, namely subsp. frutescens, subsp. microphylla and subsp. speciosa. Some regional forms are described and illustrated, but these are not formally recognised as taxa. A key to the species, subspecies and regional forms is provided, and the. nomenclature, typification, description and geographical distribution for each of the taxa are given. The multidisciplinary approach of this study provided a better understanding of the morphological, chemical and genetic variation in this relatively poorly known but potentially valuable ornamental and medicinal plant.

Magister Artium - MA / This study aims to investigate the extent to which the increasing demand for medicinal plant and the resulting pressure on local cultivators to meet the demand impact upon cultivation and gathering practices of such plants. The specific focus is on the social practices of cultivation and gathering of medicinal plants in Ebenhaezer, a small-scale peri-urban town in Matzikama in the Western Cape Province in South Africa. This study will utilize survey and in-depth interviews techniques complemented with a focus group discussion on observed cultivation and gathering practices.

No description available.

Magister Scientiae - MSc / This study aimed to evaluate the antimicrobial efficacy of medicinal hemp plant extracts to determine the antibacterial effects of indigenous Sansevieria species and exotic Cannabis sativa phytotherapy varieties. This study also assessed whether aqueous o / South Africa

Magister Scientiae - MSc / 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. / South Africa