Phenanthrenes, dihydrophenanthrenes and bibenzyls from the orchid Bulbophyllum vaginatum

Abstract

Two new phenanthrenes (4,9-dimethoxyphenanthrene-2,5-diol and 4,6- dimethoxyphenanthrene-2,3,7-triol) and two new 9,10-dihydrophenanthrenes (4- methoxy-9,10-dihydrophenanthrene-2,3,7-triol and 4,6-dimethoxy-9,10- dihydrophenanthrene-2,3,7-triol), along with six known phenanthrenes, four known 9,10-dihydrophenanthrenes no known bibenzyls and the triterpenoid friedelin were isolated and characterized from the hexane extract of the orchid Bulbophyllum vaginatum. The structures of these compounds were determined by spectroscopic analyses.