Thesis (Ph.D.)--Chulalongkorn University, 2002

The investigation of chemical constituents from Mansonia gagei Drumm., the heartwood extracts; dichloromethane, ethyl acetate and methanolic extracts, were separated to furnish sixteen compounds. by means of their physical properties and spectroscopic data, these compounds were firmly elucidated their strutures as mansorin A (1), mansorin B (2), mansorin C (3), mansonone N (4), mansonone O (5), mansonone P (6), mansonone Q (7), mansonone C (8), mansonone E (9), mansonone G (10), mansonone H (11), dehydrooxoperezinone (12), 3-methoxy-4,5-dihydroxybenzaldehyde (13), mansoxetane (14), mansonone R (15) and mansonone S (16). Among them, mansonones N, O, P, Q, R and S together with mansoxetane were characterized as new naturally occurring compounds. Moreover, those compounds were tested for their biologically activities. Mansonone C displayed the most potency activities. It showed high toxicity against brine shrimp Artemia salina Linn., larvae Aedes egyptiand a variety of cancer cell lines. In addition, it revealed antifungal activities against Cladosporium cucumerinum and Candida albicans. Mansonone E exhibited the same activities as mansonone C except for larvicidal activity. Mansorins A and B were found to be active against C. cucumerinum. Mansonone N and 3-methoxy-4,5-dihydroxybenzaldehyde possessed radical scavenging properties toward DPPH. Furthermore, mansonones G, H and dehydrooxoperezinone displayed significant activity in antithrombin assay