Prenylated bibenzyl derivatives from Lethocolea glossophylla and Radula voluta

Abstract

Phytochemical investigation of the liverwort, Lethocolea glossophylla, yielded five new prenylated bibenzyl derivatives. Their structures were elucidated by spectral analysis as 2-carboxy-3-methoxy-4,6-di-(3-methyl-2-butenyl)-5,4′-dihydroxy- bibenzyl, 2,4-di-(3-methyl-2-butenyl)-3,5,4′-trihydroxy-bibenzyl, 2,2-dimethyl-5-hydroxy-6-(3-methyl-2-butenyl)-7-[2-(4′- hydroxyphenyl)-ethyl]-chromene, 2,2-dimethyl-5-hydroxy-7-[2-(4′-hydroxyphenyl)-ethyl]-8-(3-methyl-2-butenyl)-chromene and as a bisprenylated bisbibenzyl (glossophyllin) with a chromene and a chromane moiety. From Radula voluta, the previously known bibenzyls, 2-(3-methyl-2-butenyl)-3,5-dihydroxy-bibenzyl and 2-geranyl-3,5-dihydroxy-bibenzyl, were isolated and identified. © 1997 Elsevier Science Ltd. All rights reserved