Antiglycative and Antioxidative Properties of Ethyl Acetate Fraction of Chinese Purple Yam (Dioscorea alata L.) Extracts

This study investigated the antioxidative and antiglycative abilities of flesh and peel extracts of Chinese purple yam. Among five fractions of purple yam extracts, the ethyl acetate (EA) fraction exerted the best antioxidant activity. Peel (P-EA) and flesh EA extracts (F-EA) exhibited excellent antiglycation ability by efficiently suppressing different stages of the glycation cascade, and the effect was mainly due to their antioxidant activities. The cytoprotective effect of F-EA and P-EA on methylglyoxal induced oxidative damage in HepG2 cells was also determined, and the underlying mechanism was the strengthened antioxidant defense system in HepG2 cells. Peel extract exerted better bioactivity than flesh extract, which indicated that purple yam peel, a kind of kitchen waste that is always overlooked, might serve as a promising therapeutic natural product for the prevention of diabetes or other advanced glycation end products-related diseases.