Objective: Established a assay method for the content of active component in Melastoma candidum. Method: The raw materials was hydrolyzed by adding methanol-25% hydrachloride aqeous solution(4 ∶1) mixture and the result quercetin in the solution was assayed RP-HPLC method. Shimpack VP-ODS(4.6 mm× 150 mm

5 μm) C18 column was used

the mobile phase was methanol-0.4% phosphoric acid aqueous solution (50 ∶50)

the flow rate was 1.0 mL ·min-1

and the detection wavelength was 360 nm. Result: The calibration curve of quercetin was linear in 21.2-169.6 mg ·L-1(r=0.999 5). The average recovery is 96.3%

and its RSD was 1.54%. Conclusion: The method was convenient

accurate and of good recovery and was effective for the assay of quercetin in M. candidum.