Phytochemical studies on Buxus macowanii and microbial transformation of glycyrrhetinic acid
| dc.contributor.author | Lam, Cheuk Wing | |
| dc.contributor.examiningcommittee | Hultin, Philip (Chemistry) Aluko, Rotimi (Human Nutritional Sciences) | en_US |
| dc.contributor.supervisor | Ata, Athar (Chemistry) | en_US |
| dc.date.accessioned | 2012-09-28T14:22:39Z | |
| dc.date.available | 2012-09-28T14:22:39Z | |
| dc.date.issued | 2012-09-28 | |
| dc.degree.discipline | Chemistry | en_US |
| dc.degree.level | Master of Science (M.Sc.) | en_US |
| 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.description.note | October 2012 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/9159 | |
| dc.language.iso | eng | en_US |
| dc.rights | open access | en_US |
| 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 | master thesis | en_US |