A sesquiterpene hydroquinone, Aureol (6), was isolated from extracts of Taiwanese Smenospongia sp. collected at Green Island in Taiwen. 6 was acylated to yield a series of derivatives and their structures were identified as O-Methylaureol (40)¡BAureol acetate (7)¡BAureol N,N-dimethylthiocarbamate (41)¡BO-Benzoyl-aureol (43)¡BO-4-Chlorobenzoyl-aureol (44)¡BO-4-Flurobenzoyl-aureol (45)¡BO-Nicotinoyl-aureol (46)¡BO-4-Methylbenzoyl-aureol (47) ¡BO-2-Thienylcarbonyl-aureol(48) ¡BO-2-Furoylcarbonyl-aureol (49) on the basis of 1D and 2D NMR techniques, including 1H-NMR¡B13C-NMR ¡BCOSY¡BHMQC¡BHMBC experiments. Preliminary pharmacological study revealed that some of the compounds possessed significant cytotoxicity against human cancer cells (Hepa59T/VGH¡BHela¡BKB). Kadsura philippinensis Elmer is medicinal plant which is rich in C18 type dibenzocyclooctadiene lignans. kadsuphilin A (50)¡B kadsuphilin B (51)¡B kadsuphilin C (52)¡B kadsuphilin D (53)¡B kadsurin (54)¡B kadsulignan D (55)¡Bkadsulignan K (56)¡Bbinankadsyrin A (57) ¡Bangeloyl-binankadsurin A (58) ¡Bkadsumarin A (59)¡Bschizanrin F (60) ¡Bschizanrin J (61) isolated from the lipophilic extract of aerial part of Kadsura philippinensis collected at Green Island in Taiwen. It is the first time to isolate Kadsuphilins A-D (50, 51, 52, 53). Kadsulignan D (55) and Kadsulignan K (56) were confirmed by single crystal X-ray analysis. The structures of new compounds were elucidated on the basis of 1D- and 2D-NMR techniques including COSY, HMQC, HMBC and NOESY experiments. Preliminary pharmacological study revealed that some of the compounds possessed significant cytotoxicity against human cancer cells.

This dissertation mainly discussed the investigation of three different Formosan soft corals, Xenia florida, Cespitularia sp., and Asterospicularia laurae, and also the coral medicinal herb Kadsura philippinensis. Their EtOAc extracts were investigated by chromatography. Forty-three natural products, including twenty- five new natural products were isolated and parts of their biological activities were studied. Xeniolactone A (1), a new skeleton natural product, and xeniolactones B and C (2, 3) were isolated from Xenia florida, together with eight known compounds florlide C, 9-deoxyxeniolide B, xeniolide H, florlides A and G, floridicin, blumiolide B and xeniaoxolane . In the research of soft coral Cespitularia sp.,eighe new compounds inculding four cespitularane-type diterpenes (4