||In order to discover new bioactive compounds, the chemical constituents from the organic extracts of the cultured soft coral Klyxum simplex and wild-type soft coral Cladiella hirsute were studied. 27 new eunicellin-based|
diterpenoids, klysimplexins A–X (1–24) and klysimplexin sulfoxides A–C (25–27), were isolated from a cultured soft coral Klyxum simplex. Furthermore, eight new eunicellin-base diterpenoids, hirsutalins C (28) and F–L (29–35), were isolated from the soft coral Cladiella hirsuta. The structures of compounds 1–35 were elucidated by spectroscopic methods, in particular 1D and 2D NMR
experiments. The absolute stereochemistries of 1, 3, 12, and 22 were determined by Mosher’s method. The structure of 1 was further confirmed by a single-crystal X-ray diffraction analysis. The absolute configurations of 1, 3, 12, and 22 were determined by Mosher’s method. Compounds 2, 8, 17, 20, and 29 have been shown to exhibit cytotoxicity toward a limited panel of cancer cell
lines. Compounds 10–14, 18, 19, 25–28, and 31 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. Compounds
18, 19, and 27 also could effectively reduce the level of the COX-2 protein.