Thesis (Ph. D.)--University of California, San Diego, 2009. / Title from first page of PDF file (viewed July 9, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 369-389).

BACKGROUND: Ethnobotanical knowledge continues to be important for treating illness in many rural communities, despite access to health care clinics and pharmaceuticals. However, access to health care clinics and other modern services can have an impact on the distribution of medical ethnobotanical knowledge. Many factors have been shown to be associated with distributions in this type of knowledge. The goal of the sub-analyses reported in this paper was to better understand the relationship between herbal remedy knowledge, and two such factors, age and social network position, among the Yucatec Maya in Tabi, Yucatan. METHODS: The sample consisted of 116 Yucatec Maya adults. Cultural consensus analysis was used to measure variation in herbal remedy knowledge using competence scores, which is a measure of participant agreement within a domain. Social network analysis was used to measure individual position within a network using in-degree scores, based on the number of people who asked an individual about herbal remedies. Surveys were used to capture relevant personal attributes, including age. RESULTS: Analysis revealed a significant positive correlation between age and the herbal medicine competence score for individuals 45 and under, and no relationship for individuals over 45. There was an insignificant relationship between in-degree and competence scores for individuals 50 and under and a significant positive correlation for those over 50. CONCLUSIONS: There are two possible mechanisms that could account for the differences between cohorts: 1) knowledge accumulation over time; and/or 2) the stunting of knowledge acquisition through delayed acquisition, competing treatment options, and changes in values. Primary ethnographic evidence suggests that both mechanisms may be at play in Tabi. Future studies using longitudinal or cross-site comparisons are necessary to determine the whether and how the second mechanism is influencing the different cohorts.

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Biological Sciences / Doctoral / Doctor of Philosophy

No description available.

In this study, two plant species, Schefflera umbellifera (Araliaceae) and / Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2007.

Cancer is a human tragedy that strikes and kills the lives of our beloved people. With a limited number of effective anticancer drugs from natural resources currently in use, there is a real need for new, safe, cheap and effective anticancer drugs to combat this dreaded and formidable disease. Plants have a long history of use in the treatment of cancer. Several plant-derived anticancer agents including taxol, vinblastine, vincristine, the camptothecin derivatives, topotecan and irinotecan and etoposide derived from epi- podophyllotoxin are in clinical use all over the world. In this study, two endemic plant species from the Rubiaceae and Asteraceae families, namely Anthospermum hispidulum E.Mey. ex Sond. and Eriocephalus tenuifolius DC. were investigated for their anticancer properties. The organic (methanol/dichloromethane, 1:1 v/v) extracts of both plant species were found to have moderate anticancer activity against a panel of three human cancer cell lines namely, breast MCF7, renal TK10 and melanoma UACC62 at the CSIR anticancer screen. Bioassay-guided fractionation of the organic extracts of Anthospermum hispidulum led to the isolation of an active compound which was characterised as ursolic acid. Another compound, namely scopoletin was also isolated. The compounds isolated here are known compounds, but have not previously been reported as present in the genus Anthospermum. Bioassay-guided fractionation of the organic extracts of Eriocephalus tenuifolius resulted in the isolation of 8-O-isobutanoylcumambrin B as the active constituent. This compound is reported to have been isolated from related plant species; however its biological activity is not known. The compounds pectolinagenin, hispidulin, friedelinol and tetracosanoic acid were also isolated, but did not show any significant anticancer activity. The structures of all compounds isolated in this study were elucidated using nuclear magnetic resonance spectroscopy, mass spectroscopy and also by comparison with data reported in the literature. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

The research presented in this study combines natural product chemistry with organic / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

All over Africa, traditional healers use medicinal plants to prepare medicines to treat a wide range of illnesses. One of these illnesses is sickle cell anaemia or drepanocytosis or sicklemia. This disease is particularly common among sub-Saharan Africans with a clear predominance in equatorial Africa. However, it also exists in North Africa, Greece, Turkey, Saudi Arabia and India. An estimated 50 million people are affected worldwide. A literature review on sickle cell anaemia revealed that a number of plants have anti-drepanocytosic activity. The availability and frequency of ethnobotanic use of plants were taken into account when selecting the plants investigated in this study. Cajanus cajan, Callistemon viminalis, Melaleuca bracteata var. Revolution Gold and Syzygium guineense (from DRC and South Africa) were selected for study. The selected plants were subjected to modern phytochemical analysis. A total of 8 compounds were isolated from the plants’ extracts and their structures determined by modern spectroscopic techniques (1D and 2D NMR, FT-IR and MS). S. guineense from DRC (Democratic Republic of Congo) yielded flavanonoid glycoside (A) as its major chemical constituent. The South African S. guineense afforded 4 compounds namely betulinic acid (B), sitosterol (C), friedelan-3-one (D) and a betulinic acid derivative (E). Cajanus cajan showed the presence of fatty acids, one of them was characterized as an unsaturated fatty acid (I). Callistemon viminalis afforded one compound, betulic acid (F) and Melaleuca bracteata afforded two compounds which were characterized as betulinic acid acetate (G) and ursolic acid acetate (H). CH3-(CH2)n-CH2-CH=CH-CH2-CH=CH-(CH2)n-CH2-CH2-COOH The investigation of the anti-drepanocytosis activities of the extractives and their crude extracts showed in vitro antisickling activity. Ethyl acetate crude extracts of Callistemon viminalis and Melaleuca bracteata; hexane, dichloromethane and ethyl acetate crude extracts of Syzygium guineense of DRC, betulinic acid, betulinic acid acetate and maslinic acid showed a high antisickling activity, more than 70% of normalization. The compound BF4, a fatty acid, from Melaleuca bracteata was found to have a medium activity, between 50 and 70% of normalization and oleanolic acid showed the weakest activity, between 10 and 50 % of normalization. Maslinic acid and oleanolic acid which were used for anti-sickling bioassay were isolated and characterized from Syzygium cordatum by my supervisor, Professor Shode. Others crude extracts and pure isolated compounds were found to be non-active antisickling agents. These included crude hexane and methanol extracts of Cajanus cajan; crude dichloromethane extract of Callistemon viminalis; crude dichloromethane, methanol and 80% aqueous methanol extracts of Melaleuca bracteata; crude hexane, dichloromethane, ethyl acetate, and methanol extracts of Syzygium guineense (South Africa); ursolic acid from Melaleuca bracteata and flavanone glycoside from Syzygium guineense of DRC. This is the first report of the in vitro anti-sickling activity of betunilic acid, betulinic acid acetate, oleanolic acid, and maslinic acid. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.