Comparative study on antioxidant activity of 10 Chinese herbal medicines

Ten commonly-used Chinese Herbal Medicines were investigated for their antioxidant properties of aqueous extracts using DPPH radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP) assay, and Folin-Ciocalteu (FC) method. Antioxidant properties and total phenolic content differed significantly among selected Chinese Herbal Medicines. It was found that Polygonum Cuspidatum Sieb, Scutellaria baicalensis Georgi, Prunella vulgaris L, Ligustrum lucidum Ait of aqueous extracts possessed the highest antioxidant capacities in three methods used, which may be related to its heat-clearing effect and could be potential rich sources of natural antioxidants. These extracts showed a strong ferric ion reducing activities ( ＞ 1.8 mmol/L), a high antioxidant capacity ( ＞ 70% of DPPH inhibition), and a high phenolic content ( ＞ 2.8 μg/mL). A significant relationship between antioxidant capacity and total phenolic content was found, indicating that phenolic compounds are the major contributors to the antioxidant properties of these ten Chinese Herbal Medicines.