Abstract

The antioxidant properties of enzymatic extracts from Stellaria dichotoma were evaluated using seven carbohydrases (Promozyme, Celluclast, Maltogenase, Viscozyme, Termamyl, Dextrozyme, and AMG 300L) and five proteases (Protamex, Flavourzyme, Neutrase, pancreatic trypsin, and Alcalase) (all from Novo Co., Novozyme Nordisk, Bagsvaerd, Denmark) for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, and alkyl radical scavenging activity using an electron spin resonance spectrometer. The DPPH radical scavenging activities of pancreatic trypsin and Celluclast extracts from S. dichotoma were the highest among various protease and carbohydrate extracts, and the 50% inhibitory concentration (IC(50)) values were 10.45 and 13.80 microg/mL, respectively. The Flavourzyme and Promozyme extracts of S. dichotoma showed the highest hydroxyl radical scavenging activities among the tested protease and carbohydrase extracts, with IC(50) values of 1.51 and 1.23 microg/mL, respectively. The S. dichotoma enzymatic extracts also exhibited alkyl radical scavenging activity in a dose-dependent manner. In addition, the ability of the enzymatic extracts to inhibit the oxidative damage of DNA was assessed in vitro by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. It was found that the enzymatic extracts could significantly and dose-dependently protect against hydroxyl radical-induced DNA damage. These results indicate that enzymatic extracts of S. dichotoma possess potent antioxidant activity.