Quantitative determination of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside in the roots of Polygonum cuspidatum by HPLC and elementary study on their fluorescence

AimTo establish an optimal HPLC method for the determination of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside from the roots of Polygonum cuspidatum. Methods The determination was conducted by using reversed-phase high liquid chromatography. Nucleodur 100-5 C₁₈ column (250 mm×4.6 mm ID, 5 μm), and a mobile phase program of gradient elution with iso-propyl alcohol and water at a flow rate of 0.6 mL·min^-1was employed. The fluorescence detection wavelengths were: λ_ex 334 nm, λ_em 404 nm. ResultsA good linear relationship was obtained under the optimum condition. The average recoveries were 96.7%, 99.1% for the (E)-diastereomers of resveratrol and resveratrol glucoside, 91.1%, 93.7% for the (Z)-diastereomers of resveratrol and resveratrol glucoside, respectively. The RSD of E-resveratrol and its glucoside were 1.34% and 0.72%, respectively. The RSD of Z-resveratrol and its glucoside were 1.27% and 2.08%, respectively. ConclusionThis method is accurate and reliable for the quantity analysis of the (E)- and (Z)-diastereomers of resveratrol and resveratrol glucoside in the roots of Polygonum cuspidatum.