PhD Theses

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Browsing PhD Theses by Author "Baraza, Lilechi Danstone"

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    Bioactive terpenoids, polyunsaturated fatty acids, and other constituents of two hugonia and some wild mushroom species
    (University of Dar es Salaam, 2006) Baraza, Lilechi Danstone
    University of Dar es Salaam, College of Natural and Applied Science, 2006 This Thesis reports on chemical investigations for fungitoxic, antibacterial, mosquito larvicidal and cytotoxic activity of extracts of Hugonia busseana and H. castaneifolia (Linaceae), Cantharellus mushroom species, and Termitomyces letestui, Agaricus sp. and Lactarius edulis collected in Tanzania. The root bark of H. castaneifolia yielded a new sesquiterpenoid 4a-methoxy-10-himachalen-5|3-ol (hugonianene A), the rosane diterpenoids hugorosenol and 3-deoxy-18-hydroxyhugorosenone and the aldehyde 2- hydroxyhenpentacont-2-enal, 12-hydroxy- 13-methylpodocarpa-9,l 1,13-trien-3-one, caryophyllene oxide, tetracosyl-(£)-ferrulate, hugorosenone, hugonone A and hugonone B. 12-Hydroxy-13-methylpodocarpa-9,ll,13-trien-3-one, hugorosenone and 18-hydroxyhugorosenone, were found to be active principles. H. busseana yielded a new sesquiterpenoid 4a-methoxy-5,9-oxahimachal-9-ene (hugonianene B), 18- hydroxyhugorosane, 3,18-dihydroxyhugoros-l-ene, a mixture of 12-methoxy-13- methylpodocarpa-8,ll,13-triene-3,7-dione and 12-methoxy-13-methylpodocarpa- 1,8,11,13,-tetraene-3,7-dione, hugonone B and 2-hydroxyhenpentacont-2-enal. Fungitoxic bioassay guided analysis of the Cantharellus extracts yielded as the active principles 10-hydroxy-SZT, 12Z-octadecadienoic, (9Z,14Z)-octadecadien-12-ynoic and 9- hydroxy-10is,14Z-dien-12-ynoic acid as well as ergosterol, some of which were detected by HPLC analysis only. Antimicrobial and cytotoxic extracts from L. edulis, Agaricus sp. and T. letestui yielded ergosterol, 5,8-peroxyergosterol and ergosta-5,22- dien-3|3-ol while a mixture of ergosterol and its derivatives was detected by *H NMR and GC/MS analysis of some Agaricus sp. fractions and L. edulis and T. letestui yielded mannitol, a,al,l'-trehalose and ergosta-5,22-dien-3|3-ol. C14, C15, CI6 and C18 fatty acids were also established upon GC-MS analysis of the less polar fractions from T. letestui. Structural determination of all the compounds was based on spectroscopic data.