A new rare asteriscane sesquiterpene and other related derivatives from the Hainan aeolid nudibranch Phyllodesmium magnum

► This is the first report on the phytochemical investigation of P. magnum. ► A new rare asteriscane sesquiterpene has been isolated from Phyllodesmium magnum. ► The seven known sesquiterpenes have never been reported in the genus Phyllodesmium. ► The occurrence of the metabolites supports recent chemecological study of P. magnum.