A New Approach to Develop a Standardized Method for Simultaneous Analysis of Astragaloside IV and Formononetin in Radix Astragali by High-Performance Thin-Layer Chromatography

A new high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous estimation of astragaloside IV and formononetin in Radix Astragali. Samples were employed to degrease the materials by petroleum ether (boiling point: 60-90 degrees C) and extracted by methanol, and then were alkalized and extracted with n-butanol saturated with water. Separation was achieved on HPTLC plates using petroleum ether (boiling point: 60-90 degrees C) and n-butanol saturated with water-glacial acetic acid as the mobile phase, the results of which were compared with HPLC. The well-resolved peaks for astragaloside IV and formononetin were observed at R-F values 0.43 +/- 0.02 and 0.75 +/- 0.02, respectively. The calibration curves were found linear with a wide range of concentration 1.01-10.10 mu g mu L-1 with good correlation coefficient for astragaloside IV and formononetin. The method was validated for linearity, precision, reproducibility, accuracy, and limits of detection and quantification. This simple, rapid, sensitive, economic, and reliable HPTLC method is suitable for the routine quantitative analysis and quality control of traditional Chinese medicines (TCMs) such as Radix Astragali, which can be applied for the quality control of saponins and flavonoids in other plants or extracts.