Advanced glycation end products inhibitors from Alpinia zerumbet rhizomes

Advanced glycation end products (AGES) are major factors responsible for the complication of diabetes. The present study was carried out to investigate the inhibitory activities on fructosamine adduct and alpha-dicarbonyl formations by hexane extracts of various parts of Alpinia zerumbet. Furthermore, we isolated two previously known compounds, namely 5,6-dehydrokawain (OK) and dihydro-5,6-dehydrokawain (DDK). 8(17),12-Labdadiene-15,16-dial (labdadiene) was isolated for the first time from the rhizome of A. zerumbet. The results showed that labdadiene (IC50 = 51.06 mu g/mL) had similar activity to rutin and quercetin against fructosamine adduct. The inhibition of alpha-dicarbonyl compounds formation by labdadiene was significantly higher than that of DK and DDK. Our results indicate that labdadiene is a potent antiglycation agent which was found to inhibit AGEs formation in three different steps in the pathway. These data indicate that labdadiene could be used to prevent glycation-associated complications in diabetes. (C) 2011 Published by Elsevier Ltd.