RP-HPLC Determination of Contents of Quercetin and Kaempferol in Mulberry Leaves,Twigs and Flowers

To develop the analysis method to determine the contents of quercetin and kaempferol in mulberry leaves,twigs,and flowers by HPLC.Method:The flavones in mulberry leaves,mulberry twigs,and mul- berry flowers were hydrolyted into quercetin and kaempferol with the mixed solution of methanol -25% hydrochloric acid and the quercetin and kaempferol were chromatographed on LC-10VAp HPLC with Shim-ODS( 150 mm× 4.6 mm,5μm) and detected at 368 nm.The mobile phase was methanol -0.4% phosphoric acid solution(70:30) and flow rate was 1 mL·min~(-1).Results:The linear range of quercetin and kaempfero were 0.025 -0.15μg,0.05 -0.3μg and the coefficient were 0.9999,0.9998.The average recovery were 96.2%,95.3% individually.The contents of quercetin and kaempferol of May mulberry leaves were the highest,the contents of kaempferol of mul- berry flowers were higher,the contents of quercetin and kaempferol of August mulberry leaves were the lowest.. Conclusion:The method is convenient,reliable and good reappearance for the determination of quercetin and kaempferol in mulberry leaves.