Re-evaluation of the antiglycation activity of herbal extracts using multiple antiglycation assays

The glycation process in vivo, including early intermediates, advanced glycation end products (AGEs), and crosslinked species, is involved in diabetes-associated tissue damage. Although some herbal extracts have been reported to exert antidiabetic or antiglycation effects, most studies have used co-addition assays to evaluate the inhibition of AGE formation. We re-evaluated eight herbal extracts using both co-addition and postaddition assays in distinct glycation models, namely glyceraldehyde-induced collagen and lysozyme glycation models. In the collagen model, Coptis, Cinnamomum, Connarus, and Pueraria reduced AGE-derived fluorescence under both co-addition and postaddition assays. In the lysozyme postaddition model, Cinnamomum, Connarus, and Pueraria reduced the dimer band, whereas Coptis showed a more limited effect. Multiple antiglycation assays helped distinguish inhibition of the formation of glycation-related modifications from effects on preformed glycation-related modifications and revealed distinct antiglycation profiles among the herbal extracts. Our results highlight the value of multiple glycation assays for antiglycation profiling of herbal extracts.