Four New Flavan-4-ol Glycosides from Pneumatopteris pennigera

Abstract

From the fronds of Pneumatopteris pennigera, four new flavan-4-ol glycosides, named pneu- matopterins A, B, C and D, were isolated. Their structures were determined as (2S,4R)-5,7-di-β-D-glucopyranosyloxy-6-hydroxymethyl-8-methylflavan-4-ol, (2S,4R)-5,7-di-β-D-glucopyranosyloxy-6,8-dimethylflavan-4-ol, (2S,4R)-5-β-D-glucopyranosyloxy-7-hydroxy-6-hydroxymethyl-8-methyl-4,2′′-oxo-flavan, and (2S,4R)-5-β-D-glucopyranosyloxy-7-hydroxy-6,8-dimethyl-4,2′′-oxo-flavan, respectively, on the basis of spectroscopic data and chemical correlations.