Halogenated metabolites with antibacterial activity from the Okinawan Laurencia species

The chemical compositions of five species of the red algal genus Laurencia from coastal waters of Okinawa Prefecture, Japan, have been investigated. A halogenated C-15 acetogenin, (12E)-lembyne-A, was isolated front L. marian nensis, and a halogenated sesquiterpene, (6R,9R,10S)-10-bromo-9-hydroxy-cha migra-2,7(14)-diene, was first found from L. majuscula as a naturally occur ring compound. Laurencia nidifica yielded previously known laurinterol and isolaurinterol. Samples of L. cartilaginea and L. concreta afforded no halo genated metabolites. The structures of these halogenated metabolites as wel l as their antibacterial activity against some marine bacteria are reported ., (C) 2001 Elsevier Science Ltd. All rights reserved.