New Flavonoids from the Exudate of Baccharis bigelovii (Asteraceae)

Abstract

Four flavonoids have been identified from the leaf and stem resin produced by Baccharis bigelovii (Asteraceae) in addition to twelve previously described aglycones. A flavonol (alnusin) and a dihydroflavonol (alnustinol) with 3,5,7-trihydroxy substitution had both been reported only twice before. The novel compound 2β,5,7-trihydroxy-flavanone is remarkable for its 2β-substitution at the heterocyclic ring. 7-Benzoyl-chrysin is the first flavone aglycone found as ester and the first flavonoid aglycone at all that is esterified with an aromatic acid.