Chemical Composition Of Laurencia Spp. Collected From The Seto Inland Sea Of Japan

The chemical composition of three Laurencia spp., Laurencia sp., L. okamurae and L. saitoi, which were collected from the Seto Inland Sea of Japan, has been examined. Laurencia sp. collected from the coast of Matoba Park, Takehara, Hiroshima Prefecture, contained a brominated chamigrane-type sesquiterpene (1), named matobol, as the main metabolite. The structure of matobol was determined as (+)-(2R,3R,6R,10S)-2,10-dibromochamigr-7 (14)-en-3-ol (1). This is the first time that the optically active 1 has been isolated from Laurencia. On the other hand, L. okamurae from the coast of Ikunoshima Island, Hiroshima Prefecture, produced laurinterol (2) that is a known cyclolaurane-type sesquiterpene characteristic to this species in Japan. L. saitoi from the coast of Matoba Park contained a known bromoallenic C15-acetogenin, neolaurallene (3).