Studies on the antioxidant activity of Chinese medicinal herbs

Sequential extraction with petroleum ether, chloroform–ethyl acetate, methanol, and water was carried out on 40 commonly used Chinese medicinal herbs. The antioxidant power of different fraction extracts was measured with both the DPPH assay and the FRAP assay. Ascorbic acid and butylated hydroxytoluene were used as two reference antioxidants. The total phenolic content of the extracts was measured by Folin-Ciocalteu method. The fraction extracts showed different antioxidant activity in the two assays; however, there was a significant positive correlation between the DPPH assay and the FRAP assay. Methanol fraction extracts generally demonstrated stronger antioxidant power and higher total phenolic content than did the others. The results suggest that Radix Sanguisorbae, Cortex cinnamomi, Herba taxilli, Semen arecae, and L., Cinnamomum cassia Presl., Taxillus sutchuenensis (Lecomte) Danser, Areca catechu Linn. and Scutellaria baicalensis Georgi contain relatively high values in antioxidant power and/or high total phenolic content. This study is the first comprehensive antioxidant activity evaluation among Chinese medicinal herbs. It demonstrates that most Chinese medicinal herbs are also useful in preventing various degenerative diseases