Lemnalol acetate, ylangene-type sesquiterpenoid isolated as natural product from the soft coral genus Lemnalia collected in Okinawa

Compounds 1 and 2 were isolated from soft corals of the genus Lemnalia on Ishigaki Island, Okinawa Prefecture. Analysis of the spectral data obtained from nuclear magnetic resonance (NMR) analysis and comparison of the optical rotations with those in previous literature revealed that compound 2 was lemnalol, which was previously isolated from L. tenuis on Ishigaki Island. Compound 1 was identified as lemnalol acetate, in which the OH at the 4-position of lemnalol was acetylated. Compound 1 was previously synthesized artificially; however, this is the first report as a natural product. Compounds 1 and 2 exhibited moderate cytotoxicity against S1T cells, which are rampant adult T-cell leukemia cells in the Kyushu and Okinawa regions.