Phenanthrene and other aromatic constituents of Bulbophyllum vaginatum

Two new phenanthrenes (4-methoxyphenanthrene-2,3,7-triol and 4-methoxyphena nthrene-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-trio l and its 9,10-dihydro derivative, 3,4',5-trihydroxy-3'-methoxybibenzyl (tr istin), 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 dete rmined through spectroscopic analysis. (C) 1999 Elsevier Science Ltd. All r ights reserved.