Yang-Chang Wu, Ping-Jyun Sung, Wei-Hsien Wang, Yu-Wei Chang, Yung-Husan Chen, Wu-Fu Chen, Ting-Jang Lu, Zhi-Hong Wen, Michael Yen-Nan Chiang, Li-Chung Hu, Jui-Hsin Su, and Wei-Hsuan Yen
A new norcembranoidal diterpene, 1-epi-sinulanorcembranolide A (1), and a new cembranoidal diterpene, flexibilin D (2), were isolated from the soft corals, Sinularia gaweli and Sinularia flexibilis, respectively. The structures of new metabolites 1 and 2 were elucidated by spectroscopic methods, and compound 2 was found to significantly inhibit the accumulation of the pro-inflammatory iNOS and COX-2 proteins of the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. In addition, S. flexibilis yielded a known cembrane, 5-dehydrosinulariolide (3); the structure, including its absolute stereochemistry, was further confirmed by single-crystal X-ray diffraction analysis.