Soft corals of the genus Sinularia have been proved to yield a wide variety of secondary metabolites. In order to search for novel bioactive substances from marine organisms, we have investigated the secondary metabolites of the soft corals Sinularia leptoclados and Sinularia sandensis. Chromatographic separation of the organic extracts of the Formosan soft coral Sinularia leptoclados, collected at Dongsha Atoll of the South China Sea, led to the isolation of four new steroids (1-3 and 11), along with an unexpected artificial sterol (5) and six known 9,11-secosteroids (4 and 6-10). In addition, the acetone extract of the soft coral, Sinularia sandensis, collected at the Tsau-Lou-Cho Island off the southwestern coast of Taiwan, yielded three novel sesquiterpenoids (12-14). The structures of the isolated metabolites were elucidated by extensive spectroscopic analyses (IR, UV, mass, optical rotations, CD, 1D and 2D NMR) and by comparison of the spectral data with those of the related known compounds. Moreover, the absolute configuration of 12 was established by application of modified Mosher¡¦s method. The cytotoxicity against of P-388 (mouse lymphocytic leukemia), HT-29 (human colon adenocarcinoma), and A-549 (human lung epithelial carcinoma) cells of metabolites 1-4 and 6-14 as well as the anti-HCMV (human cytomegalovirus) activities of metabolites 4, 10, 11, and 13 were evaluated. Metabolites 2, 4 and 6-10 exhibited significant activity against P-388 cell in vitro (IC50¡Ø4 mg/mL).

In order to discover bioactive secondary metabolites, we have studied the chemical constituents from the organic extracts of soft coral Sinularia flexibilis. This study had led to the isolation of eighteen natural compounds 1¡V18, including seven new cembrane-type diterpenoids, flexibilisolides C¡VG (1, 2, 3, 6, 7), flexiblilisin C (5), 11,12-secoflexibillin (4) along with eleven know compounds. The structure of compounds 1¡V18 were established by detailed spectral data analysis (IR, MS, 1D, 2D NMR) and by comparison of the spectral data with those of the related known compounds. The cytotoxicity of compounds 1¡V6, 8¡V14, 16¡V18 against the Hela (human cervical epitheloid carcinoma), SK-Hep1 (human liver carcinoma), and B16 (human melanin carcinoma) tumor cell lines were screened. Compounds 1, 9, 12, and 13 showed moderate activity toward the Hela and SK-Hep1 tumor cells. Compound 12 also showed moderate activity toward the B16 cells, and compound 14 showed activity toward the Hela cells. On the other hand, compounds 1, 9, 13, and 17 were found to show significant activity against the accumulation of the pro-inflammatory iNOS and COX-2 protein at 10 £gM. Compounds 2¡V4, 7, 8, 10, 14, 16 were found to show activity against the accumulation of the pro-inflammatory iNOS protein at 10 £gM.

Our chemical investigation on the soft coral Sinularia facile which was collected off the coast of Kengting, Taiwan, has led to the isolation of ten metabolites 1¡Ð10, including four cembranoids and six polyhydroxylated steroids. Cembranoids isolated are two new natural compounds, (3E,7E,11E,15E)-cembra-3,7,11,15-tetraen-1-ol (1) and (1R*,12R*,3E,7E,10E,15E)-cembra-3,7,10,15-tetraen-12-ol (2), and two known compounds diepoxycembrene A (3) and isocembrol A (4). Moreover, five new polyhydroxylated steroids, cholest-5-ene-1£\,3£]-diol- 11£\-monoacetate (5), cholesta-5,24-diene-1£\,3£] -diol-11£\-monoacetate (6), cholesta-5,24-diene-1£\,3£]-11£\-triol (7), 24- methylenecholesta-5-ene-1£\, 3£]-diol-11£\,18-diacetate (8) and 24(S)- methylcholest-5-ene-1£\,3£]-diol- 11£\-monoacetate (9), and one known compound, 24-methylenecholest-5- ene-1£\,3£],11£\-triol (10). The chemical structures of these compounds (1¡Ð10) were elucidated by spectroscopic evidences (IR, MS, 1D NMR, and 2D NMR) and by comparison of the spectral data of these compounds in the literature. Cytotoxicity of these compounds toward various cancer cell lines has also been determined.

In order to search for bioactive compounds, we have studied the chemical constituents from the organic extracts of five soft corals including Sinularia lochmodes, Sinularia nanolobata, Sinularia grandilobata, Sinularia depressa and Lobophytum crassum. This study had led to the isolation of eighteen natural compounds 1¡Ð18, including seven new compounds, lochmolins A ¡Ð G (1 ¡Ð 7) from S. lochmodes, a new compound nanolobatolide (8) featuring with a new carbon skeleton from S. nanolobata, two new compounds grandilobatin G (9) and sinugrandisterol E (10) from S. grandilobata, a new compound depressoloide A (11) and a known compound sarcophytol L (12) from S.depressa, and three new compounds crassumolides G¡ÐI (13¡Ð15) along with three known compounds durmolides B and C (16 and 17) and sinularolide C (18) from L. crassum. The structures of compounds 1¡Ð18 were established by detailed spectral data analysis (IR, MS, 1D & 2D NMR) and by comparison with the spectral data of the related known compounds. The relative stereochemistries of compound 8 was further confirmed by X-ray single-crystal diffraction analysis. Among them, compounds 13¡Ð15 and 16¡Ð17 were found to show significant activity against the accumulation of the pro-inflammatory iNOS and COX-2 proteins at 10 £gM.

Investigation on the chemical constituents of the Formosan soft coral Sinularia gibberosa, collected by hand using scuba off the coast of Kenting, had led to the isolation of seven new cembranoids , gibberorenes A-G¡]2-8¡^, three new sterols, gibberoketosterol B¡]10¡^, gibberoepoxysterol¡]11¡^, gibberoketosterol C ¡]12¡^ along with two known compounds, (1Z,3E,7E,11S,12S,14S)-11,12-epoxycembra-1,3,7 -trien-14-ol¡]1¡^and gibberoketosterol¡]9¡^. The structures of 1-12 were elucidated on the basis of extensive spectroscopic analysis, including IR, MS, 1D, and 2D NMR. Cytotoxicities of 1-12 against a limited panel of cancer cell lines were also evaluated. Among these metablites, compounds 9 and 11 were found to exhibit moderate cytotoxicity toward MCF-7, A549, MDA-MB-231, and HepG2 tumor cells. The ability of 9 and 10 to inhibit the pro-inflammatory iNOS and COX-2 expression of LPS-stimulated RAW264.7 macrophage cells has been also estimated.

Corals are the dominant species of the coral reefs. The diversity of species is classified by traditional morphological traits, especially relied on the calcious deposits-sclerites. The formation of sclerites may be affected by the environmental conditions; therefore, some controversies may exist. The ambiguities may be clarified with molecular approaches. Five soft coral species, Lobophytum pauciflorum, Sinularia leptoclado, Sinularia flexibilis, Sarcophyton sp., Nephthea erecta were chosen for this study. The total mitochondrial DNA sequences were determined by PCR and primer walking. The genome contains 18562 bp, 18732 bp, 18752 bp, 18806 bp, 18716 bp separately, which harbors 14 protein-coding genes (ATP6¡BATP8¡BCOI¡BCOII¡BCOIIII¡BCYTB¡BND1¡BND2¡BND3¡BND4¡BND4L¡BND5¡BND6¡BMSH), 2 rRNA and only 1 tRNA genes. The phylogenetic relationship of alcyonacea corals were analyzed and compared with published sequences. The possibility of using a short ¡§DNA bar-code sequence¡¨ of the mitochondria as an alternative for species identification may be feasible. We found the short DNA signature sequences for these five corals. They may speed up the identification of corals in the long run.

Marine organisms have attracted much attention as potential source for drugs over recent years. Soft corals have yielded many bioactive metabolites. Some of them have been examined for their pharmacological properties. For the process of drug discovery, we have examined bioactive metabolites from the organic extracts of two soft corals Sinularia gibberosa and Sarcophyton sp. collected off Formosan coast. This study had led to the isolation of forty-two natural products (1¡V42), including one new £]-caryophyllene-type sesquiterpenoid (1), four new xeniaphyllane-type norditerpenoids (2, 14, 16, and 17), fourteen new xeniaphyllane-type diterpenoids (3¡V13 and 18¡V20), one novel nor-humulene (15), seven new xeniaphyllane-type diterpenoids (21¡V26) with cyclic peroxyhemiketal (3,6-dihydro-1,2-dioxin-3-ol) moiety, and one new steroid (27), along with five known compounds (28¡V32) from Sinularia gibberosa. Three new cembrane-type diterpenoids (33¡V35), along with seven known cembranolides (36¡V42) were isolated from Sarcophyton sp. The structures of metabolites 1¡V42 including their stereochemistry have been established by detailed spectroscopic analyses, particularly mass, 2D NMR (1H¡V1H COSY, HMQC, HMBC, and NOESY) spectroscopy and by comparison with the related physical and spectral data from other known compounds. In above metabolites, two compounds (8, 9) exhibited cytotoxicity against the growth of MCF-7, Hep 3B, Ca9-22 cancer cell lines. Furthermore, nine compounds (4, 8, 9, 11, 12, 13, 21, 31, 39) exhibited cytotoxicity against the growth of MDA-MB-231, Hep G2 and A-549 cancer cell lines.

<p> Colonies of the soft coral Sinularia polydactyla collected from the vicinity of Panjang island, Jepara region, Central Java, Indonesia were tested to examine their antibacterial properties. </p> <p> Chemical analysis and bioassay-directed purification by repetitive column chromatography using Vibrio harveyi as tester strain revealed that S. polydactyla possesses antibacterial properties against this test strain. Purification gives a mixture of esters, which inhibited the growth of the marine biofilm forming bacterium, V. harveyi with an EC50 value of 0.075 mg/10 mL of culture medium. </p> <p> Chemical synthesis of the esters Hexadecyl palmitate (1 ), hexadecyl stearate (2), octadecyl palmitate (3), and octadecyl stearate (4) was accomplished from the alcohols and fatty acid acyl halides. Each purified ester was characterized by NMR and MS. Comparison of the MS for these authentic synthetic samples with that for the biologically derived sample showed that the latter was composed predominantly of esters 1 and 3. The individual esters were tested against V. harveyi. Compound 1 was active and 4 was less active, while 2 and 3 were inactive. Hence, 1 is the major active compound against V. harveyi in the natural mixture. </p> / Thesis / Master of Science (MSc)

Marine invertebrates have been found to be a rich source of bioactive secondary metabolites. In order to search for bioactive compounds, we have studied the chemical constituents from the organic extracts of two Formosan soft corals, Sinularia Scabra and Lemnalia flava. This study had led to the isolation of eight natural compounds, including two new sesquiterpenoids, scabralin A (1) and scabralin B (2) along with two known compounds (3 and 4) from Sinularia scabra, and two new sesquiterpenoids, flavalin A (5) and flavalin B (6) along with three known compounds (4, 7 and 8) from Lemnalia flava. The structures of these compounds were established by the detailed spectral analysis (IR, MS, 1D, 2D NMR) and by comparison of the spectral data with the related known compounds. Lobohedleolide (9), with a great quantity in Lobophytum crassum, have also been modified to compounds 10−19 by chemical conversions with the corresponding reactants via EDC-coupling with an aid of HCl salt of DMAP to yield the related esters and amides.The cytotoxicity of compounds 1, 3−8 and 10¡V19 against the MCF-7 (human breast adenocarcinoma), WiDr (Human colon adenocarcinoma), Daoy (human medulloblastoma), Hep2 (human laryngeal carcinoma), Hep G2 (human liver carcinoma), CCRF-CEM (human T-cell acute lymphoblastic leukemia), and DLD-1 (human colon adenocarcinoma) tumor cell lines were determined. Compound 1 showed moderate activity against the growth of Daoy, Hep2, MCF-7, Hela and CCRF-CEM. Both 15 and 16 exhibited a moderate cytotoxicity against the growth of Hep G2, and compounds 10, 12¡V14, 17 and 18 showed a weak cytotoxicity of it. Compounds 10, 12 and 16¡V18 were found to exhibit moderate inhibition against the growth of CCRF-CEM. Compounds 10, 16 and 18 showed weak activity against the growth of DLD-1. Furthermore, compounds 10, 12 and 14-19 were found to show significant activity against the accumulation of the pro-inflammatory iNOS protein at 10 £gM.