Antioxidative activities and the total phenolic contents of tonic Chinese medicinal herbs

Chinese medicated diet is an everyday practice in China. In this study, 16 commonly used soup making tonic Chinese medicinal herbs were selected for antioxidative capacities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP), and the total phenolic contents of these herbal extracts were measured by the Folin-Ciocalteu method. It confirmed that drinking tonic soups could supplement total antioxidants intake. Amongst the tested herbal extracts, extracts of Canarium album Raeusch., Flos caryophylli and Fructus amomi were found to have the highest antioxidative activities in both DPPH and FRAP assays. Their antioxidative activities were comparable to ascorbic acid and butylated hydroxytoluene. Thus, these herbs are safe and inexpensive sources of natural antioxidants. A significant relationship between the antioxidative effects and total phenolic contents were found, indicating phenolic compounds are the major contributor of antioxidative capacities of these herbs. In addition, a strong correlation between DPPH assay and FRAP assay implied that antioxidants in these herbs were capable of scavenging free radicals and reducing oxidants.