Quantitative determination of multiple components in Herba Epimedii using a single reference standard: a comparison of two methods

Multi-component analysis has gained significant attention in the quality control of Traditional Chinese Medicines. However the high cost of reference standards and their limited availability have posed major challenges. Practical solutions to these problems include use of a single reference standard contained in the analyte as an internal standard. In the first part of this study, using Herba Epimedii as an example, we selected icariin as the external standard to determine the content of icariin and used the same compound as the internal standard to simultaneously determine the other four components (epimedin A, epimedin B, epimedin C and baohuoside I). Icariin is the main compound found in Herba Epimedii. In the second part of the study, we selected a different compound (rutin) that is not found in Herba Epimedii but is closely related to icariin in chemical and physical properties as the internal standard to calculate the content of the other five components listed above. There was no significant deviation in the results obtained in the two alternate methods as compared to the traditional calibration equation method. The two methods yielded similar results and can therefore be used in the routine quality control of Herba Epimedii and other herbs.