Determination of the antioxidative activities of herbs harvested in Japan by oxygen radical absorbance capacity methods

Abstract

Oxygen radical absorbance capacity (ORAC) is a method for evaluating antioxidant capacities of both hydrophilic (H-ORAC) and lipophilic compounds (L-ORAC). In this study, we evaluated the antioxidant capacities of eight herbs (Italian parsley, coriander, celery white, watercress, rocket, mustard green, basil, and corn salad) by ORAC. Basil showed the highest antioxidant capacity among the herbs assessed in this study. The harvest season affected both the H-and L-ORAC values of the herbs, except for the H-ORAC value of Italian parsley. The ratios of H-to L-ORAC values of the herbs ranged from 36-86%. Total polyphenol contents of herbs were positively correlated with H-ORAC values, and were also affected by harvest season. We found that isoquercitrin and rutin but not ferulic acid contributed to the seasonal change in the H-ORAC value of basil.