Diversity of proanthocyanidin content in soybean landraces

Proanthocyanidins (PAs) are natural plant antioxidants, whose radical scavenging activities (RSA) degrade harmful free radicals. In the current study, PA contents were analyzed in 52 soybean [Glycine max (L) Merril] landraces having different seed coat colors. PA was extracted by HCl-Butanol method; RSA was determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and quantified using spectrophotometer. Soybean cultivar KaiFengKuoZhuangqingDou had the highest PA content, 946 ABS.ml g-1, followed by Peking, 860 ABS.ml g-1. Both the cultivars had black seed coats. Chasengoku 81Go had the highest PA content (485 ABS.ml g-1) among the landraces with brown seed coat color. In landraces with green seed coats, PA content ranged from 1 to 6 ABS.ml g-1. In landraces with yellow seed coats PA content ranged from 0 to 10 ABS.ml g-1. The RSA was directly proportional to PA content with a high correlation coefficient (r2 = 0.9724), so PA content contributed highly to RSA. Reasons for these wide variations in PA content and RSA within the same colored landraces are discussed.