Hirsutalins A-H, eunicellin-based diterpenoids from the soft coral Cladiella hirsuta

Abstract

Eight new eunicellin-base diterpenoids, hirsutalins A-H (1-8), were isolated from the soft coral Cladiella hirsuta. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute configuration of 1 was determined by Mosher's method. Compounds 1, 5, and 6 have been shown to exhibit cytotoxicity toward several cancer cell lines. Compounds 2-4 and 8 were found to display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein, with compound 2 also effectively reducing the level of COX-2 protein.