Five new compounds were isolated from the soft coral Cespitularia sp.collected in Green Island, Taiwan. They are G8-7-7-A (1), G8-9-15-30-A(2), G8-10-B (3), G8-7-6-A (4) and G8-7-5-A (5). All of them belong to diterpenes with three methyl groups at C-16, C-17 and C-18, and an exocyclic double bond between C-4 and C-18. Compounds 1 and 2 are bicycle norditerpenes. G8-7-7-A (1) possesses a 6/13 ring and has an endocyclic double bond between C-7 and C-8. It also contains a hydroxyl group at C-6, a ketone group at C-12 and a lactone ring between C-10 and C-11. G8-9-15-30-A (2) is different from 1 at the lactone ring position. The lactone ring of 2 is between C-10 and C-12, and the ketone group is at C-11. So compound 2 possesses a 6/14 bicyclic ring system. Compounds 3-5 are cespitularin diterpenes, which belong to a 5/6/12 tricyclic ring. They all have an endocyclic double bond between C-7 and C-8. G8-10-B (3) contains an £\-hydroxy-£],£^-epoxy-£_-acetoxy furan and a hydroxyl group at C-6. The only difference between compounds 3 and 4 are substiuents at C-20. The C-20 position of 4 is an acrylic group, while compound 3 has an acetoxyl group at C-20. G8-7-5-A (5) contains an £^-hydroxy-£\,£]-unsaturated-£^-lactone function and a ketone group at C-6. Their structures were elucidated by mass, IR, 1D and 2D NMR spectroscopic analysis.

To investigate the bioactive constituents for evaluation of cytotoxicity, six new diterpenoids¡]1-6¡^and one known compound¡]7¡^were isolated from a sample of soft coral Cespitularia sp. collected in Taiwan.These diterpenoids were divided into three skeletons: GXX-7-L3-1-2¡]1¡^, G8-5-L2-8-1¡]3¡^and G8-4-L3-9-1¡]4¡^are verticillane skeleton. GXX-7-L3-4-1¡]2¡^possesses a cespitularane skeleton. G8-4-L3-7-1¡]5¡^, G8-4-L3-8-1¡]6¡^and cespitularin E ¡]7¡^ contain a norverticillane skeleton.Compound 1 contains an £\,£]-unsaturated ketone at C-11, C-12 and C-10, an ethyl ester group at C-20 position, and a hydroxyl group at C-6 position. There is a £\-hydroxy-£],£^-epoxy-£_-hydroxy furan in compound 3. Compound 4 contains a methyl group at C-20 position, an epoxy ring at C-7 and C-8 position, and loses a hydroxyl group at C-6. Compound 2 has two acetoxyl groups at C-6 and C-20 position. Compound 5 contains an £\,£]-unsaturated ketone at C-11, C-12 and C-10, and olefinic double bond at C-7 and C-8 conjugated with ketone group at C-6 .The olefinic double bond at C-7 and C-8 is oxygenized to an epoxy ring and the ketone at C-6 is reduced to a hydroxyl group in compound 6.The ketone in compound 5 is reduced to a hydroxyl group in compound 7. All of these structures were elucidated on basis of extensive spectroscopic analysis and chemical derivatization.The configuration of hydroxyl group at C-6 in 1 was determined to be £] orientation by using Mosher¡¦s method. All of the isolated diterpenoids were tested against a panel of human tumor cell lines.

This dissertation mainly discussed the investigation of three different kinds of Formosan soft corals, Cespitularia hypotentaculata Roxas, C. taeniata May and Junceella juncea, as well as Formosan star-anise, Illicium arborescens Hayata. Their EtOAc extracts were investigated by intensive chromatography. Twenty new natural products were isolated and purified and their biological activities were studied. The chemical investigation of soft coral Cespitularia hypotentaculata and C. taeniata resulted in the isolation of twenty natural products, including ten new natural products, designated as cespihypotins B, W¡VZ (6, 1 ¡V 4), cespihypotone (5), cespitaenins A (10) and F-H (7-9) as well as fourteen know compounds (21-34). Compounds 1-3 were nor-verticillane-type nor-diterpenes. Compounds 4-6 were verticillane-type diterpenes. Cespitaenins A and F (10 & 7) were nor-verticillane-type nor-diterpenes. Cespitaenins G and H (8 & 9) were verticillane-type diterpenes. Three new briarane-type natural products, juncenolides L-N¡]11-13¡^ toghther with and one know compound (35) were isolated from Junceella juncea. The study of Formosan star anise, Illicium arborescens Hayata has afforded seven new compounds (14-20). Two of them were stereoisomer, named 2,3-dide- hydro-5-O-methyl-11-epiillifunone E (14) and 2,3-Didehydro-5-O-methylillifunone E (15). The others were 8,9-secoprezizaane-type sesquiterpenes (16-20). All the structures of above compounds were elucidated by physical and spectroscopic analyses (IR, mass, UV, optical rotation and NMR), and also by comparisions with the published data. Cytotoxicity and in vitro anti-inflammatory activities were measured by Dr. Yao-Haur Kuo of National Research Institute of Chinese Medicine and Dr. Tsong-Long Hwang of Chang Gung University. The biological activities of compounds against MCF-7 (Human breast adenocarcinoma), Doay (Human medulloblastoma), WiDr (Human colon adenocarcinoma), Hela (Human cervical epitheloid carcinoma) cell lines and effects of compounds on superoxide anion generation and elastase release by human neutrophils in response to FMLP/CB. were tested. The effects of compounds 9-12 on superoxide anion generation and elastase release by human neutrophils in response to FMLP/CB were 6.19, 6.72, 7.56 and 6.72 respectively. The IC50 of compounds 14 and 19 against MCF-7, Doay, WiDr and Hela were 9.0, 7.1, 11.2, 10.9 and 5.1, 6.3, 10.9, 6.24 £gg/mL, respectively.

This dissertation mainly investigates the constituents of one species of sponge (Ircinia formosana) and three species of soft corals¡]Sinularia flexibilis¡BCespitularia hypotentaculata and Clavularia viridis¡^. These organisms were extracted with EtOAc and analyzed them with chemical methods. Twenty three new natural products were isolated and the cytotoxicity of these copounds was tested and evaluated. Four new C22-sesterterpenoids were isolated from the sponge Ircinia formosana, and designated as irciformonins A-D (1-4). In the investigation of the soft coral Sinularia flexibilis, nine new cembranes were purified, and they were called sinuladiterpenes A-I (5-13). Six new diterpenes, cespihypotins Q-V (14-19) were obtained from the soft coral Cespitularia hypotentaculata. In addition, the soft coral Clavularia viridis afforded four new prostanoids, designated claviridic esters A-D (20-23). The structures of these metabolites including their stereochemistries have been established by detailed spectroscopic analyses, particularly 2D NMR (1H¡V1H COSY, HMQC, HMBC, and NOESY) spectroscopy and mass and by comparison with the related physical and spectral data of known compounds. Cytotoxicity of the isolated compounds was measured by Dr. Kuo Yao-Haur, Institute of Chinese Medicine. Irciformonins C (3) and D (4) from sponge Ircinia formosana showed the cytotoxicity against WiDr (Human colon adenocarcinoma) with ED50 at 6.7 and 4.9 £gg/mL, respectively. Cespihypotin T (17) was found to exhibit the inhibition against Daoy (Human medulloblastoma) and WiDr (Human colon adenocarcinoma) at ED50 9.3 and 7.5 £gg/mL. Claviridic esters A (20) and B (21) exhibited significant cytotoxicity against the growth of Hep2 (Human hepatoma) at ED50 0.19 nad 0.16 £gg/mL, respectively. Claviridic ester B (21) also showed significant cytotoxicity against Daoy (Human medulloblastoma) tumor cells at ED50 0.18 £gg/mL.

This dissertation mainly discussed the investigation of two different Formosan soft corals, Junceella juncea and Cespitularia taeniata, as well as twigs and needles of Taxus sumatrana (Taxaceae). Their EtOAc extracts were investigated by intensive chromatography. Twenty-seven new natural products were isolated and parts of their biological activities were studied. Three new briarane-type natural products, Juncenolides I-K¡]1-3¡^, were isolated from Junceella juncea. In the research of soft coral Cespitularia taeniata, eleven new compounds inculding two new skeleton natural products ¡]4-5¡^of 6/13 bicyclic, one cespitularane-type diterpene (6), four verticillane-type diterpenes (7-10), one 10, 11-seco verticillane-type diterpene (11), three sesquiterpenes (12-14) were purified. Chemical investigation of Taxus sumatrana (Taxaceae) resulted in isolation of thirteen new taxane diterpenes, including tasumatrols R-U, W, Z ¡]15-18, 20, 23¡^, six wallifoliol-type diterpenes, tasumatrols V, Y¡]19, 22¡^ and 11(15¡÷1), 11(10¡÷9) diabeotaxane diterpenes , taiwantaxins B-C ¡]25-26¡^ ; 2(3¡÷20) abeotaxane diterpene, tasumatrol X ( 21¡^; one 11(15¡÷1) abeotaxane diterpene, taiwantaxin A¡]24¡^; one 6/8/6 ring system diterpene, taiwantaxin D¡]27¡^,. All the structures of above compounds were elucidated by physical and spectroscopic analyses (IR, mass, UV, optical rotation and NMR), and also by comparisions with the published data. Cytotoxicity and in vitro anti-inflammatory activities were measured by Dr. Kuo Yao-Haur, respectively. The biological activities of compounds 1-14 against MCF-7 (Human breast adenocarcinoma), Doay (Human medulloblastoma), WiDr (Human colon adenocarcinoma), Hela (Human cervical epitheloid carcinoma) , compounds 12 and 14 showd weak cytotoxicity. Tasumatrol Y (22) exhibited mild cytotoxicity against human liver carcinoma (Hepa2) with ED50 at 3.5 £gg/mL. Taiwantaxin B (25) showed marked cytotoxicity against human prostate cancer (PC-3) cell lines with an IC50 of 5.02 +0.6 £gg/mL (8.96 +0.34 £gM).

Eight new metabolites (1-5 and 7-9) and one known compound were isolated from the acetone/methylene chloride (1:1)extracts of the Formosan soft coral Cespitularia hypotenta-culata. These compounds can be divided into five groups: cespitularin I (1), having the verticillane skeleton, cespitularin J (2), that possesses the norverticillane skeleton, cespitularin K (3)¡B6-acetoxycespitularin F (4) and cespitularin L (5), possessing the cespitularane skeleton, (24S)-3£],11-dihydroxy-5£],6£]-epoxy-24-methyl-9,11-secocholestan-9-one (6), 3£],11-dihydroxy-5£],6£]-epoxy-9,11-secocholestan-9-one (7), and 3£]-hydroxy-5£],6£]-epoxy-9-oxo-9,11-secogorgo-stan-11-ol (8) are secosterols, and xenia diterpene, cespolide A (9). All of these structures were elucidated by extensive spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.

Four new diterpenoids, cespitulactones A-B (1-2), C4B1 (7) and E3A (8), were isolated from the soft coral Cespitularia taeniata collected in Taiwan, at a depth of 25 m, together with five known compounds, cespitularin F (3), 6-O-acetylcespitularin F (4), cespitularin D (5), flaccidoxide-13-acetate (6) and florlide A (9). Compound 1 possesses a novel structure with a bond cleavage between C-10 and C-11, and having a 14-membered lactone ring junction between C-10 and C-12. Compounds 2 and 8 have the verticillane skeleton, and compound 9 possesses the cespitularane skeleton. Their structures were elucidated on the basis of extensive spectroscopic analysis and chemical derivatization. The isolated compounds were also evaluated for cytotoxicity toward human cancer cell lines. Compound 1 exhibited significant cytotoxicity against human cervical epitheloid carcinoma (HeLa) and colon adenocarcinoma (DLD-1) cancer cells with IC50 of 3.69 and 9.98 £gg/mL, respectively. Flaccidoxide-13-acetate (6) showed mild activity against human medulloblastoma (Daoy) and colon (WiDr) cancer cells at 16.9 and 13.8 £gg/mL, respectively.

Five new diterpenes, GN67-12-5-4-2 (1)¡BGN67-12-6-4-2 (2)¡BGN67-20-4-3 (3)¡BGN67-25-6-1 (4)¡BGN67-12-5-12-1 (5) and four known terpenoides, GN67-12-5-12 (6)¡BGN67-28-5-3-3 (7)¡BGN67-28-5-4 (8)¡BGN67-23-4 (9) were isolated from the methylene chloride solubles of the Formosan soft coral Cespitularia hypotentaculata. Three new cytotoxic sesquiterpenes, GN78-14-3a-B (10)¡BGN78-22-8I-B (11)¡BGN78-17-3a-B (12) and five known terpenoides, GN78-12-5-B-G (13)¡BGN78-14-3a-N (14)¡BGN78-22-8-W (15)¡BGN78-22-8-H (16)¡BGN78-24-5-Q (17) were isolated from the Formosan soft coral Paralemnalia thyrsodes Three known compounds, GN72-9-8-J (18)¡BGN72-7-4-2 (19)¡BGN72-19-6-8-E (20) were isolated from the methylene chloride solubles of the Formosan soft coral Dendronephthya divaricata The structure of 4 was further confirmed by X-ray crystallographic analysis and the configuration of the hydroxyl at C-6 of 5 was further determined by Mosher¡¦s reactions. It was suggested that the C-6 has the S configuration. The inhibition of these metabolites toward the pro-inflammatory proteins (iNOS and COX-2) expression was also investigated. Compound 17 showed more specific inhibition against the up-regulation of the pro-inflammatory iNOS protein of LPS-stimulated RAW264.7 macrophage 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