||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 3α,11β-dihydroxy-24-methyl-22,25epoxy-5α- furostan-18,20β-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, 3β,11-dihydroxy-24- methylene-9,11-secocholest-5-en-9-one (8), 3β,11-dihydroxy-24-methyl-9, 11-secocholest-5-en- 9-one (9) and 3β-hydroxy-11-acetoxy-24-methylene-9, 11-secocholest-5-en-9-one (10) were isolated from S. gibberosa. Among them, compounds 1–3, are new products. All metabolites 1–10 are steroids.|
The structures of 1–10 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.