Briaexcavatins V-Z, discovery of new briaranes from a cultured octocoral briareum excavatum

Abstract

[[abstract]]Five new briarane derivatives, briaexcavatins V-Z(1-5), have been isolated from a cultured octocoral Briareum excavatum. The structures of compounds 1-5 were established by spectroscopic methods. Single-crystal X-ray diffraction data for 2 confirmed the structure. Briarane 4 possesses an unprecedented 8, 9-epoxy moiety. The relationships between 13C NMR chemical shifts and the conformations of briaranes possessing an 11, 12-epoxy group are described. Briaranes 1, 3, and 4 have displayed weak inhibitory effects on superoxide anion generation by human neutrophils. Briarane 1 was found to show mild inhibitory effects on human neutrophil elastase release and 5 exhibited mild activity to enhance human neutrophil elastase release. © 2009 The Chemical Society of Japan