Three new oxylipins from an Okinawan marine sponge Plakortis sp.

Three new oxylipins, manzamenone P (1), 6'-O-methylmanzamenone K (2), and 6'-O-ethylmanzamenone K (3), were isolated from an Okinawan marine sponge Plakortis sp. Manzamenone P (1) is a unique oxylipin possessing two long acyl chains and a novel core unit consisting of spiro-bonded cyclohexanone and beta-keto-gamma-lactone rings. The structures of 1-3 were elucidated on the basis of spectroscopic evidences including 2D NMR and FABMS/MS spectra as well as a comparison of DFT calculated NMR data with those experimental data. (C) 2015 Elsevier Ltd. All rights reserved.