Isolation and structure elucidation of onnamide a, a new bioactive metabolite of a marine sponge, Theonella sp.

Marine sponges of the genus Theonella have been shown to elaborate diverse chemical structures with interesting biological activities.1 We have recently described the isolation of misakinolide A, a dimeric 40-membered lactone having antitumor activity from a species of Theonella. 1a In our screening for bioactivity in marine organisms occurring in Okinawan waters, another species of Theonella gave an extract showing antiviral activity. Bioassay-guided separation led to the isolation of an active constituent, onnamide A (1)2 which belonged to a class of metabolites new to Theonella species. We herein report the isolation and structure elucidation of onnamide A (1).