Bioactive terpenes from the soft coral Heteroxenia sp. from Mindoro, Philippines

A marine soft coral species of the genus Heteroxenia collected from Mindoro Island, Philippines yielded two cadinene sesquiterpenes, (+)-alpha-muurolene (1) and a novel derivative (+)-6-hydroxy-alpha-muurolene (2), as well as the biologically active polyhydroxysterol, sarcoaldosterol A (3). The structure of the novel compound was unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct and long range 13C-1H correlations) and mass spectrometric (EIMS) data. All compounds were active against the phytopathogenic fungus Cladosporium cucumerinum. The isolated terpenes were also active in the brine shrimp lethality test.