Validation of HPLC method for quantitative determination of active compounds in Thai traditional herbal medicine to treat gastrointestinal disease

Abstract

Quality control is essential for determining the quality and consistency of medicinal plant products before their use. Thatbunjob is a Thai herbal formulation included in the National List of Essential Medicines for treating gastrointestinal diseases. This study aimed to develop and validate a high-performance liquid chromatography method for determining active compounds in Thatbunjob. The main compounds, gallic acid, chebulagic acid, rutin, and eugenol, were determined following the International Conference on Harmonization (ICH) guidelines. The method was validated in terms of linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), and found to be linear, with a correlation coefficient (R2) ranging from 0.9995 to 0.9998. The LOD and LOQ values calculated from the calibration curve ranged from 7.29 to 20.29 and 22.09 to 61.48 µg/mL, respectively. The method also exhibited acceptable precision, with relative standard deviation values lower than 2%. The accuracy of the method was evaluated based on the recovery percentages, and found to be within an acceptable range (90.12–105.39%). The validated protocol developed in this study was employed to analyze the concentration levels of gallic acid, chebulagic acid, rutin, and eugenol in eight different Thatbunjob products commercially available in Thailand. The performance parameters show that the developed and validated method is appropriate for the quantitative determination of gallic acid, chebulagic acid, rutin, and eugenol in Thatbunjob.