Phenanthrene and other aromatic constituents of Bulbophyllum vaginatum

Abstract

Two new phenanthrenes (4-methoxyphenanthrene-2,3,7-triol and 4- methoxyphenanthrene-2,3,6,7-tetrol) and two new 9,10-dihydrophenanthrenes (5- methoxy-9,10-dihydrophenanthrene-2,3,7-triol and 4-methoxy-9,10- dihydrophenan-threne-2,3,6,7-tetrol), along with the known 4,6- dimethoxyphenanthrene-2,3,7-triol and its 9,10-dihydro derivative, 3,4',5- trihydroxy-3'-methoxybibenzyl (tristin), dihydroferulic acid, p-coumaric acid, 3,4-dihydroxybenzoic acid and (±)-syringaresinol were isolated from the dichloromethane extract of the orchid Bulbophyllum vaginatum. The structures of these compounds were determined through spectroscopic analysis.