Bibenzyl derivatives from the orchid Bulbophyllum protractum

Two new bibenzyl derivatives were isolated from the orchid Bulbophyllum protractum and designated bulbophyllin and bulbophyllidin. In addition batatasin-III (3,3'-dihydroxy-5-methoxy bibenzyl), 3,3',5-trimethoxybibenzyl, aloifol-I (3',4-dihydroxy-3,5-dimethoxybibenzyl), 3,3'-dimethoxy-4,5-methylenedioxybibenzyl, flavidin (2,7-dihydroxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran), dihydroconiferyl alcohol, stigmasterol and sitosterol were isolated. The structures of bulbophyllin and bulbophyllidin were established as 2,3'-dihydroxy-3-methoxy-4,5-methylenedioxybibenzyl and 2,3'-dihydroxy-3,5-dimethoxybibenzyl, respectively, from spectral and chemical evidence. Copyright (C) 1996 Elsevier Science Ltd