Isolation of Pyranocoumarins from Angelica Gigas

Abstract

A mixture of diastereomers of the coumarin glycoside 3′-O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (1), along with six known pyranocoumarins, columbianoside (4), marmesin (5), 3′-hydroxy-3′,4′-dihydroxanthyletin (6), decursin (7), decursinol angelate (8), and isoimperatorin (9), were isolated from the roots of Angelica gigas Nakai. The racemic compound 1 was successfully separated by preparative HPLC to obtain a new isomer 3′(S)-O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (2), and a known isomer 3′(R)-O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (3). The absolute configuration of compounds 2 and 3 was determined by comparison of optical rotation and NMR data of their acid hydrolysis products.