Simultaneous determination of trans-resveratrol and emodin in Polygonum cuspidatum root extracts and pharmaceutical preparations by high performance liquid chromatography

A simultaneous determination of trans-resveratrol and emodin by high performance liquid chromatography (HPLC) in Polygonum cuspidatum root, extracts and dosage forms was developed and validated. HPLC analysis was performed on a reversed phase C-18 column using the gradient formed by 0.1% (v/v) phosphoric acid in water and acetonitrile at the flow rate of 1 mL/min with photodiode array detection at 280 run. The linear regression analysis data for the calibration plots for trans-resveratrol and emodin showed good linear relationship with correlation coefficients (r(2)) 0.9995 +/- 0.0002 and 0.9995 +/- 0.00025, in the concentration range 0.5-2.0 and 0.25-1.00 mu g per injection, respectively. The method was validated for precision and recovery. The limit of detection (LOD) and limit of quantification (LOQ) were 3.06, 9.27 and 1.03, 3.13 ng per injection, respectively, for trans-resveratrol and emodin. Statistical analysis confirmed that the method is accurate, precise and selective and can be applied for the identification and quantification of trans-resveratrol and emodin, simultaneously, in herbal extracts and pharmaceutical preparations.