New norterpene cyclic peroxides and a new polyketide from the marine sponge Diacarnus megaspinorhabdosa

Two new norterpenes dicarperoxides M and N and one new polyketide diacarnustin C were isolated from the marine sponge Diacarnus megaspinorhabdosa. Detailed spectroscopic analysis guided the elucidation of their structure. Structurally, dicarperoxides M and N incorporate a typical norterpene cyclic peroxide core, while diacarnustin C is noteworthy in that it contains an alpha, beta-unsaturated ester unit linked to a furan ring. Dicarperoxides M and N displayed moderate cytotoxicity against THP-1 (IC50 values of 15.3 and 20.6 mu M, respectively) and u937 cells (IC50 values of 13.4 and 25.7 mu M, respectively). (C) 2021 Elsevier Ltd. All rights reserved.