A novel diterpene and six new sesquiterpenes from the sea hare Aplysia dactylomela

Abstract

Aplydactylonin D (1), a diterpene possessing an unprecedented carbon skeleton with a 3-(p-tolyl)-7,7a-dihydrocyclopenta[b]pyran-6(2H)-one core, and six new brominated sesquiterpenes, aplydactylonins E–K (2–7), were isolated from the sea hare Aplysia dactylomela. Their structures and absolute configurations were elucidated by the interpretation of spectroscopic data, quantum chemical calculations, and electronic circular dichroism (ECD) analyses. All of the isolated compounds were evaluated for their cytotoxicity against HepG2, A549 and MCF7 cells. Aplydactylonin G (4) exhibited cytotoxicity against the A549 cell line with an IC₅₀ value of 8.15 ± 0.96 μM.