RP-HPLC simultaneous determination of six flavonoids in Radix Astragali

Objective:To develop an RP-HPLC method for the simultaneous determination of six flavonoids in Radix Astragali.Methods:The reversed phase HPLC system consisting of a Diamonsil C18 column (250 mm×4.6 mm,5 μm ) and a mixture of acetonitrile and 0.05% phosphoric acid as the mobile phase was adopted with gradient elution. The column temperature was set at 35 ℃ and the flow rate was 1.0 mL·min-1. The absorbance was monitored at 210 nm and 250 nm.Results:The linear response ranges were 3.31-33.12 μg·mL-1(r = 0.9996) for formononetin,2.52-25.20 μg·mL-1(r=0.9992) for formononetin-7-O-β-D-glucoside,6.64 -66.40 μg·mL-1(r=0.9992) for calycosin,10.80-108.0 μg·mL-1(r=0.9994) for calycosin-7-O-β-D-glucoside,2.42-24.16 μg·mL-1(r=0.9993) for 9,10-dimethoxypterocarpan-3-O-β-D-glucoside and 2.79-27.90 μg·mL-1(r=0.9994) for 2'-hydroxy-3',4'-dimethoxy-isoflavane -7-O-β-D-glucoside ,respectively (n=6). The average recoveries (n=9) of six flavonoids were greater than 95.0%,and RSD were less than 2.9%.Conclusion:The results demonstrated that the method had adequate accuracy and selectivity to measure the concentrations of six flavonoids in Radix Astragali.