Antioxidative activity of five flavones glycosides from corn silk (Stigma maydis)

Five flavones glycosides (i.e., 2''-O-α-l-rhamnosyl-6-C-3''deoxyglucosyl-3'-methoxyluteolin, ax-5'-methane-3'-methoxymaysin, ax-4''-OH-3'-methoxymaysin, 6,4'-dihydroxy-3'-methoxyflavone-7-O-glucoside, and 7,4'-dihydroxy-3'-methoxyflavone-2''-O-α-l-rhamnosyl-6-C-fucoside) were successfully isolated from corn silk and identified. We evaluated their antioxidant activity among in vitro assay systems. Most of the flavones glycosides showed a high antioxidant activity in a lecithin liposome system, as well as a strong scavenging activity against radicals such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and hydroxyl radicals. The study indicated that the corn silk flavonoids, especially 6, 4'-dihydroxy- 3'-methoxyflavone-7-O-glucoside, may be beneficial natural food antioxidants.