Chemical Constituents from the Aerial Parts of Aster koraiensis with Protein Glycation and Aldose Reductase Inhibitory Activities

Two new eudesmane-type sesquiterpene glucosides, 9 beta-O-(E-p-hydroxycinnamoyl)-1 beta,6 beta-dihydroxy-trans-eu-desm-3-en-6-O-beta-D-glucopyranoside (1) and 9 alpha-O-(E-p-hydroxycinnamoyl)-1 alpha,6 alpha-11-trihydroxy-trans-eudesm-3-en-6-O-beta-D- glucopyranoside (2), were isolated by the activity-guided fractionation of an EtOAc-soluble fraction from the aerial parts of Aster koraiensis. A new dihydrobenzofuran glucoside, (2R,3S)-6-acetyl-2-[1-O-beta-D-glucopyranosyl)-2-propenyl]-5-hydroxy-3-methoxy-2,3-dihydrobenzofuran (3), was also isolated, in addition to 15 known compounds. The structures of 1-3 were determined by spectroscopic data interpretation. All of the isolates were evaluated for in vitro inhibitory activity against the formation of advanced glycation end-products and rat lens aldose reductase.