We have investigated the chemical constituents of the organic extracts of soft coral Lobophytum crassum, collected at Dongsha Atoll. This study has led to the isolation of eight new compounds, including six cembrane-type diterpenoids 1-6 and two a-tocopherol-type compounds 7 and 8 The chemical structures of compounds 1-8 were elucidated by extensive analysis of 1D, 2D NMR spectroscopic data (1H and 13C NMR¡B1H-1H COSY¡BHSQC¡BHMBC¡BNOESY), UV, IR, CD and MS. Compounds 1 and 6 possess unprecedented diterpenoid skeletons. The absolute configurations of compound 1 were determined using a modified Mosher¡¦s method. Compounds 1-8 were tested against A-549 (human lung epithelial carcinoma)¡BHT-29 (human colon adenocarcinoma)¡BP-388 (mouse lymphocytic leukemia) tumor cell lines. Compounds 1, 7, and 8 displayed modest cytotoxicity against P-388 cell line with ED50 values of 3.2, 3.2, and 2.7 £gg/mL, respectively. Compound 8 exhibited marginal cytotoxicity against H-29 cell line with an ED50 value of 3.9 £gg/mL.

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.

In order to search for novel bioactive compounds, we have investigated the secondary metabolites of the soft corals Nephthea erecta, Lobophytum durum, and Sarcophyton ehrenbergi. Chemical examinations on the organic extracts of N. erecta, have resulted in the isolation of six new sesquiterpenoids (1-6), a new calamenene-type sesquiterpene with a mercaptan group, erectathiol (7), a new tri-nor-eudesmadienone (8), two known sesquiterpenoids (9 and 10), one novel seco-germacrane sesquiterpene (11), three unexpected artificial 19-oxygenated steroids (12-14), as well as twelve new polyhydroxylated steroids (15-26). Furthermore, twelve new cembranolids, durumolides A-L (27-38), three unprecedented hemiketal cembranoids, durumhemiketalolides A-C (39-41), six previously described cembranolids (42-47), together with one known metabolite, peridinin (48), were isolated from the acetone extracts of L. durum. Chemical investigation of S. ehrenbergi, has led to the isolation of a known ceramide (49), two new cerebrosides, sarcoehrenosides A (50) and B (51), along with three previously characterized cerebrosides (52-54). The structures of the isolated metabolites were elucidated through extensive spectroscopic analyses, while the relative stereochemistry of 10 and 44 were further confirmed by X-ray diffraction analyses. Moreover, the absolute configurations of 24, 25, 29, 34, 38, and 43-45 were established by application of modified Mosher¡¦s method. The cytotoxicities, antibacterial activities, anti-inflammatory effects, and inhibition assay of HCMV (human cytomegalovirus) endonuclease activities of these isolated metabolites were evaluated in vitro.

Investigation on the chemical constituents of the EtOH extract of the soft coral Lobophytum sarcophytoides, collected off the coast of Dongsha Atoll, Taiwan, has led to the isolation of ten natural compounds 1¡V10, including four new cembrane-type diterpenoids, Sarcophytolins A¡VD (1¡V4) and one new polyhydroxylated steroid 23, 24-Dimethyl-cholesta-5, 16-diene-3£], 20£\-diol (5) along with five know compounds 6¡V10¡CThe structure of compounds 1¡V10 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 relative stereochemistries of compound 5 was further confirmed by X-ray single-crystal diffraction analysis. The cytotoxicity of compounds 1¡V10 against the Daoy (human medulloblastoma), Hep-2 (human laryngeal carcinoma), MCF-7 (human breast adenocarcinoma), CCRF-CEM (human T-cell acute lymphoblastic leukemia), and DLD-1/WiDr (human colon adenocarcinoma) tumor cell lines were determined. Compounds 6, 8, 9, and 10 exhibited moderate cytotoxicities against the tested tumor cells. Furthermore, compounds 1, 2, 4, 6, and 10 were found to show significant activity against the accumulation of the pro-inflammatory iNOS protein at 10 £gM.

Soft corals of the genus Lobophytum (Alcyoniidae) have been well recognized as a rich source of various secondary metabolites that have attracted much interest for the natural products chemists due to their structural complexity and remarkable pharmacological activities such as cytotoxicity, antibacterial activities, anti-inflammatory properties, and antiviral activity. Twelve cembrane diterpenes including six new secondary metabolites 1−6 were isolated organic extracts of soft coral Lobophytum durum collected at Dongsha Atolls. The structures of these six new cembranolides were determined by 1H, 13C, DEPT, COSY, HMBC, HSQC, NOESY, IR and Mass spectra. Furthermore, these six new secondary metabolites 1−6 were evaluated in vitro for the cytotoxicity against A-459 (human lung carcinoma), HT-29 (human colon adenocarcinoma), and P-388 (mouse lymphocytic leukemia) cancer cell lines, and antiviral activity against HCMV (human cytomegalovirus) cells.

Marine invertebrate have been found to be a rich source of bioactive secondary metabolites. During the course of our investigation on the bioactive chemical constituents from marine invertebrates, twenty-eight metabolites have been isolated from two soft coral Lobophytum crassum and Dendronephthya griffini. Investigation on L. crassum has led to the isolation of fourteen compounds, including seven new cembranoids, crassumolides A¡VG (1¡V7), and three new glycolipids (2R)-1-hydroxy -3-hexadecyloxy-propyl-£]-D-arabinopyranoside (8), (2R)-1-hydroxy-3- octadecyloxy-propyl-£]-D-arabinopyranoside (9), and (2R)-1-acetoxy-3- hexadecyloxy-propyl-£]-D-arabino-pyranoside (10), coupled with four known compounds, lobohedleolide (11), 17-dimethylaminolobohedleolide (12), sinulariol A (13), and denticulatolide (14). Ten new steroids, griffinisterones A¡VJ (15¡V24), were isolated from the soft coral D. griffini, while a known, 15-chlorogriffinsulfate (25), and three new polychlorinated acyclic compounds¡Agriffinsulfate (26), 15-chlorogriffinol (27), and griffinol (28), were also purified from the same organism. Structures of these metabolites were identified as new natural products by extensive spectroscopic methods. Except for the use of 2D NMR, the 24-epimers of 15 and 16 were identified by a single-crystal X-ray crystallography on 15. Lobohedleolide (11), obtained in large quantity in L. crassum, has also been modified to 29¡V34 by chemical conversion. Oxidation with meta-chloro-peroxybenzoic acid (MCPBA) afforded compounds 29 and 30, and with selenium dioxide led to the formation of 31. Compound 34 is the product of O-coupling reaction of 11 with 1-hydroxybenzotriazole (HOBt). Over 99¢Mdiastereoselectivity was observed in the process of Henbest hydroxyl-directed epoxidation on 11 to yield 32. EDC-coupling with an aid of HCl salt of DMAP afforded methylester 33 in high yield, and proved the absolute stereochemistry of 3. The cytotoxicity and anti-inflammatory activities of the natural and modified compounds were also discussed herein.

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.