1H NMR Quantification of Polydatin and Emodin in Huganning, a Chinese Patent Herbal Medicine

Huganning, a Chinese patent medicine, has been used in clinical practice for the treatment of hepatitis in China for more than 20 years, and its main physiologically active components are polydatin and emodin. In this study, a rapid and accurate proton nuclear magnetic resonance method for the quantification of these constituents was developed. 4-Nitrochlorobenzene was selected as an internal standard, and the signals for polydatin at δ 6.44 ppm and emodin at δ 7.54 ppm were chosen for the quantification. Validation of the method was performed in terms of specificity, precision, and stability. The results indicated that the method was precise and in line with the China Food and Drug Administration guidance. The method has been successfully applied to characterize tablets and capsules obtained from six pharmaceutical companies. This study indicated that the rapid 1 H NMR method is more suitable for the quality control of Huganning than the high-performance liquid chromatography method. Graphical Abstract