Re-evaluation of the Anti-glycation Activity of Herbal Extracts Using Multiple Anti-glycation 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 anti-glycation 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 post-addition 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 post-addition assays. In the lysozyme post-addition model, Cinnamomum, Connarus, and Pueraria reduced the dimer band, whereas Coptis showed a more limited effect. Multiple anti-glycation assays helped distinguish inhibition of the formation of glycation-related modifications from effects on preformed glycation-related modifications and revealed distinct anti-glycation profiles among the herbal extracts. Our results highlight the value of multiple glycation assays for anti-glycation profiling of herbal extracts.