In order to discover for bioactive compounds, we have studied the chemical constituents from the organic extracts of soft coral Klyxum molle. This study had led to the isolation of 16 eunicellin-type diterpenoids, including ten new compounds, klymollins A¡VJ (1¡V10), along with six know compounds 11¡V16. The structures of compounds 1¡V16 were established by spectroscopic methods and by comparison of the spectral data with those of the related known compounds. It is noteworthy to mention that compounds 1¡V10 represent the first example of eunicellins possessing a C-11/C-17 epoxide. The absolute configuration of 4 was determined using a modified Mosher¡¦s method. The cytotoxicity of compounds 1¡V8 and 11¡V16 against the A549 (human lung epithelial cells), HepG2 (human hepatocellular carcinoma), Hep3B (human hepatocellular carcinoma), MCF-7 (human breast adenocarcinoma)¡BMDA-MB231 (human breast adenocarcinoma) tumor cell lines were determined. Compound 11 showed cytotoxicity toward A549 tumor cells (IC50 value of 3.14 £gg/mL) and compounds 15 and 16 were found to exhibit cytotoxicity toward HepG2 tumor cell (IC50 values of 3.82 and 2.50 £gg/mL). Compounds 6 and 7 were found to show significant activity against the accumulation of the pro-inflammatory iNOS and COX-2 protein at 1 £gM.

In order to discover marine bioactive compounds, we investigated the chemical constituents from the organic extracts of soft coral Klyxum molle. Repeated column chromatography on the ethyl acetate extract of soft coral Klyxum molle, resulted in the isolation of nine new eunicellin-type diterpenoids, klymollins V¡ÐZ (1¡Ð5) and klyxumollins A¡ÐD (6¡Ð9), and four known compounds (10¡Ð13). The structures of new compounds were determined on the basis of extensive spectroscopic data (IR, MS, 1D and 2D NMR) and by comparison of the spectral data with those of the related known compounds. The cytotoxicity of compounds 1¡Ð13 was evaluated against five tumor cell lines including CCRF-CEM (human T cell lymphoblast-like cell line), K562 (human erythromyeloblastoid leukemia cell line), Molt 4 (human acute lymphoblastic leukemia cell line), T47D (human ductal breast epithelial tumor cell line) and DLD-1 (human colorectal adenocarcinoma cell line). Compound 2 exhibited weak cytotoxicity toward three cancer cells (CCRF-CEM, Molt 4 and T47D) and compounds 4 and 9 showed weak cytotoxicity against CCRF-CEM cancer cells. Compound 11 was found to exhibit stronger cytotoxicity toward CCRF-CEM cancer cells (ED50 values of 4.2 £gg/mL). On the other hand, compound 3 showed weak activity against the accumulation of the pre-inflammatory cytokine IL-6 in LPS-induced macrophages, at a concentration of 25 £gM.