Simultaneous LC Determination of Major Constituents in Red and White Peony Root

A reversed phase high performance liquid chromatography method was established for the simultaneous determination of eight major constituents, namely gallic acid, paeoniflorin sulfonate, catechin, albiflorin, paeoniflorin, benzoic acid, pentagalloylglucose and benzoylpaeoniflorin in red and white peony roots, the two commonly used traditional Chinese medicinal herbs. The optimal conditions of separation and detection were achieved on a C₁₈ analytical column with a gradient mobile phase consisting of acetonitrile and 0.015% phosphoric acid at the flow rate of 1.0 mL min^?1 and detection wavelength set at 230 nm. All calibration curves showed good linear regression (r>0.9995) within test ranges. This method provided good reproducibility with overall intra-and inter-day precision of less than 5% and 4% and good accuracy with recovery of more than 93%, respectively. The method was successfully applied to determine 71 samples of red and white peony roots collected from different areas. The results indicated that the contents of eight compounds varied significantly among the samples determined, which mainly resulted from processing procedure and habitat variation. The roots of Paeonia veitchii Lynch. contained a much higher amount of gallic acid and pentagalloylglucose than that of Paeonia lactiflora Pall., which could be used to distinguish the two similar species.