Development of a Method for Simultaneous Determination of Two Stilbenes and Four Anthraquinones from Polygonum Cuspidatum by RP-HPLC

Background: Polygonum cuspidatum Sieb. et Zucc. (named Huzhang in China) is a traditional and popular Chinese medicinal herb used in removing jaundice, clearing heat-toxin, improving blood circulation, expelling stasis, dispelling wind and dampness, repelling phlegm, and suppressing cough. It is widely used in drug and functional food fields and distributed throughout the world, including in China, Japan, and North America. Objective: To control the quality of Polygonum cuspidatum, an effective, reliable, and simple method for simultaneous determination of two stilbenes (polydatin, resveratrol) and four anthraquinones (emodin, physcion, rhein, and anthraglycoside B) was developed and validated for the first time in this study by reversed-phase HPLC (RP-HPLC). Methods: Separation was carried out on Agilent C₁₈ column (250 × 4.6 mm I.D., 5 μm) with acetonitrile and 0.10% aqueous phosphoric acid as mobile phase and gradient elution at a flow rate of 0.8 mL/min. Detection was conducted with mobile wavelength at 30°C. Results: Good validation of the method including linearity, precision, repeatability, and recovery was performed. The contents of the studied analytes are significantly different, and resveratrol and rhein in particular existed in greater fluctuation among the samples. Conclusion: A simple, reliable, and sensitive method has been successfully established and applied to the analysis for simultaneous determination of the target compounds in 11 batches of samples. Highlights: Separation and quantitative analysis of two stilbenes and four anthraquinones from P. cuspidatum were developed by RP-HPLC. This method is convenient, sensitive, and accurate and can provide a reliable basis for further applications of P. cuspidatum in drug or food fields.