dc.contributor.supervisor |
Ata, Athar (Chemistry) |
en_US |
dc.contributor.author |
Lam, Cheuk Wing
|
|
dc.date.accessioned |
2012-09-28T14:22:39Z |
|
dc.date.available |
2012-09-28T14:22:39Z |
|
dc.date.issued |
2012-09-28 |
|
dc.identifier.uri |
http://hdl.handle.net/1993/9159 |
|
dc.description.abstract |
This thesis describes phytochemical studies on Buxus macowanii, a medicinal plant collected from South Africa and the fungal transformation of glycyrrhetinic acid (71), a triterpenoid found in Glycyrrhiza plants.
The crude methanolic extract of B. macowanii was active in the acetylcholinesterase inhibition assay (IC50 = 30 μg/mL). Chemical investigation of its alkaline dichloromethane extract afforded five novel triterpenoidal alkaloids, 31-hydroxybuxatrienone (56), macowanioxazine (57), 16α-hydroxyma-
cowanitriene (58), macowanitriene (59), and macowamine (60), along with two known Buxus bases, Nb-demethylpapillotrienine (61) and moenjodaramine (62). Compounds 56, 57, and 61 exhibited different level of AChE inhibitory activities with compound 56 being significantly active (IC50 = 8.0 μM).
Glycyrrhetinic acid (71) was incubated with Curvularia lunata (ATCC 12017) for ten days to afford one metabolite which was characterized by NMR spectral data as known biotransformed product, 3-oxo-glycyrrhetinic acid (85). This metabolite was previously obtained through biotransformation of 71 by using other fungi. |
en_US |
dc.rights |
info:eu-repo/semantics/openAccess |
|
dc.subject |
Buxus |
en_US |
dc.subject |
macowanii |
en_US |
dc.subject |
AChE |
en_US |
dc.subject |
Alzheimer |
en_US |
dc.subject |
biotransformation |
en_US |
dc.title |
Phytochemical studies on Buxus macowanii and microbial transformation of glycyrrhetinic acid |
en_US |
dc.type |
info:eu-repo/semantics/masterThesis |
|
dc.degree.discipline |
Chemistry |
en_US |
dc.contributor.examiningcommittee |
Hultin, Philip (Chemistry) Aluko, Rotimi (Human Nutritional Sciences) |
en_US |
dc.degree.level |
Master of Science (M.Sc.) |
en_US |
dc.description.note |
October 2012 |
en_US |