Constituents of the roots of Pueraria lobata inhibit formation of advanced glycation end products (AGEs)

Two isoflavone C-glucosides, puerarin (1) and PG-3 (2), a but-2-enolide, (+/-)-puerol B (3), two isoflavone O-glucosides, daidzin (4) and genistin (5), and three pterocarpans, (-)-medicarpin (6), (-)-glycinol (7) and (-)-tuberosin (8), were isolated from a MeOH extract of the roots of Pueraria lobata, using an in vitro bioassay based on the inhibition of the formation of advanced glycation end products (AGEs) to monitor chromatographic fractionation. The structures of 1-8 were determined by spectroscopic data interpretation, particularly by 1D- and 2D-NMR studies, and by comparison of these data with values in the literature. All of the isolates (1-8) were evaluated for their inhibitory activity on AGEs formation in vitro. Of these, puerarin (1), PG-3 (2), and (+/-)-puerol B (3) exhibited more potent inhibitory activity than the positive control aminoguanidine.