Antioxidant activities of several Chinese medicine herbs

The antioxidant activity (AA) of ethyl acetate extracts of Caesalpinia sappan, Lithospermum erythrorhizon, Anemarrhena asphodeloides, Paris polyphylla and Illicium verum were tested in refined peanut oil at 60 ± 0.5 °C. The concentrations of the extracts added were 0.20% (w/w). The rate of oxidation was assessed by the measurement of peroxide value (PV) and calculation of such characteristics as induction period (IP), when PV reaches 20 meq kg−1, protection factor (PF), which is the ratio of `IP of the sample with additiveʹ and `IP of the sample without additiveʹ, and AA (the ratio of `IP increase of the sample with extractʹ and `IP increase of the sample with butylated hydroxytolueneʹ). All of C. sappan, L. erythrorhizon extracts and their combinations were found to be high effective in peanut oil. But the extracts of A. asphodeloides, P. polyphylla and I. verum slightly decrease the formation of peroxides in peanut oil as compared with pure oil.