The HPLC condition was expressed as follows:The mobile phase was acetonitrile (solvent A) and water (solvent B) , a gradient system of solvent A from 10% to 64% in 40 minwith flow rate 1 mL/min was used. The ABTS solution was supplied with a flow rate of 0.5 ml/min. The chromatogram was recorded at 210 nm and 280 nm as the positive peaks, and the visible detector was set at 734 nm to measure the decrease in the ABTS radicals as the negative peak