Flavonoid aglycones and a dihydrostilbene from the frond exudate of Notholaena nivea

Abstract

The frond exudate of the fern Notholaena nivea var. nivea contains a novel dihydrostilbene as a major constituent. This compound was identified by spectroscopic methods as 3-hydroxy-5,4-dimethoxy-6-carboxylic bibenzyl, which is isomeric to the earlier reported notholaenic acid. The exudate of N. nivea also contains flavonoid aglycones which form patterns that are characteristic for the two varieties. The distribution of notholaenic and isonotholaenic acids in further Notholaena species is reviewed.