Screening and identification of inhibitors of advanced glycation endproduct formation from microalgal extracts.

The formation and accumulation of advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of many chronic diseases, such as aging, Alzheimer's disease, diabetes and diabetic complications. The present study was aimed to investigate the inhibitory effects of the extracts from nine microalgae on the formation of AGEs by using in vitro models and identify key antiglycation constituents of the microalgae. A BSA-glucose model with simulated physiological conditions was used to evaluate the inhibitory effect on total AGE formation. A BSA-MGO model was used to study the inhibitory activity against the dicarbonyl-induced AGE formation. The results showed that the aqueous acetone extracts exhibited stronger antiglycation activity than the other extracts (ethyl acetate and dichloromethane) and that the marine microalgal extracts were generally more effective than the freshwater ones. Their inhibitory rates ranged from >60% to 90% when used at a concentration of 0.5 mg mL-1. HPLC-DAD and UPLC-Q-TOF-MSE analyses revealed that fucoxanthin was likely the principal component which contributed to the observed antiglycation activity. Further analysis established a highly significant positive correlation (R2 > 0.95) between the fucoxanthin content and the antiglycation activity of the aqueous acetone extracts. This is the first report on the antiglycation activity of fucoxanthin. The findings of the present study have not only identified a promising inhibitor of AGE formation, but have also identified a valuable natural source of this phytochemical which possesses great potential to be developed as functional food ingredients and pharmaceutical products to help reduce health risks associated with AGEs.