In our continuing study on the chemical constituents of Taiwanese soft corals, the EtOAc extracts of a gorgonian coral Isis hippuris and a alcyonarian coral Sinularia gibberosa were investigated, respectively. Seven compounds, including 3£\,11£]-dihydroxy-24-methyl-22,25epoxy-5£\- furostan-18,20£]-lactone (1), 3-acetyl-2-deacetyl-22R-hippurin-1 (2), hippuristerone F (3), hippurin-1 (4), 22-epi-hippurin-1 (5), 3-acetyl-2- desacetyl-22-epi-hippurin-1 (6) and 2-desacetyl-22-epi-hippurin-1 (7) were isolated from I. hippuris. Three metabolites, 3£],11-dihydroxy-24- methylene-9,11-secocholest-5-en-9-one (8), 3£],11-dihydroxy-24-methyl-9, 11-secocholest-5-en- 9-one (9) and 3£]-hydroxy-11-acetoxy-24-methylene-9, 11-secocholest-5-en-9-one (10) were isolated from S. gibberosa. Among them, compounds 1¡V3, are new products. All metabolites 1¡V10 are steroids. The structures of 1¡V10 were determined by physical and spectral analysis, including IR, MS, 1D NMR (1H, 13C) and 2D NMR ( 1H-1H COSY, HMQC, HMBC and NOESY ) and by comparison with the related physical and spectral data of the known compounds. The cytotoxicity of the isolates against the P-388 ( mouse lymphocytic leukemia ), A-549 ( human lung adenocarcinoma ) and HT-29 ( human colon adenocarcinoma ) cancer cell lines were studied. Compound 9 and 10 showed significant cytotoxicity against P-388 cancer cell line. Metabolites 6 and 8 showed significant cytotoxicity against P-388 and HT-29 cancer cell lines. Compound 2, 4 and 5 exhibited potent cytotoxicity against the growth of P-388, A-549 and HT-29 cancer cell lines.

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.

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.