Phenolic antioxidants in beans and their effects on inhibition of radical-induced DNA damage

Four bean varieties with different hull colors (white, brown, red, and black) were extracted with 80% acetone and evaluated for their antioxidant potential. Red, brown, and black bean extracts were able to effectively retain supercoiled DNA against 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced radical damage at the concentration levels (5, 10, 50, and 100 ppm) tested. Delphinidin, cyanidin, and procyanidins B2, C1, C2, and X were identified in red, brown, and black bean hull extracts, whereas white bean hull extract contained only a small amount of flavonoids. Vanillic, caffeic, p-coumaric, ferulic, and sinapic acids were the main phenolic acids identified in bean hull extracts.