Two new subergane-based sesquiterpenes from a Taiwanese Gorgonian coral Subergorgia suberosa

Chemical investigation of the ethyl acetate extract of the Taiwanese Gorgonian coral Subergorgia suberosa has resulted in the isolation of two new subergane-based sesquiterpenes, subergorgiol (1) and 2beta-acetoxysubergorgic acid (2), along with four known compounds, subergorgic acid methyl ester (3), 2beta-acetoxy methyl ester of subergorgic acid (4), 2beta-hydroxysubergorgic acid (5), and subergorgic acid (6). The structures of the new metabolites 1 and 2 were determined on the basis of extensive spectral analyses. Subergorgiol (1) may be the biosynthetic precursor of 2-6. Compound 3 was found to exhibit moderate cytotoxicity against the growth of HeLa cancer cells.