[Quality evaluation standards of Rehmanniae Radix based on "pharmacological activity-chemical component group" and...

This study aims to address the bottlenecks in the current quality control system for traditional Chinese medicine(TCM), such as the poor rationality in quality control standards and the difficulty in reflecting the overall quality of medicinal materials, with Rehmanniae Radix as an example. By strengthening the efficacy-component correlation and considering various pharmacological effects of Rehmanniae Radix, this study establishes a systematic and rational control standard with chemical component groups as indicators. The establishment of holistic quality control indicators for TCM by comprehensive expression of the effectiveness of TCM can scientifically and comprehensively reflects the intrinsic quality of Rehmanniae Radix and enhance the quality standards of TCM and its products, providing reference for the high-quality development of TCM. This study explored the efficacy-component relationship of the main chemical components, glycosides, in fresh Rehmanniae Radix and raw Rehmanniae Radix during intervention in the kidney-Yin deficiency model, thus constituting the pharmacological activity-chemical component group structure. Finally, a chemical component group fingerprint was established, and quantitative characterization of the two active components was conducted for Rehmanniae Radix samples from different authentic production areas and stored for different years. Twelve and 13 characteristic peaks were identified in the chemical component group fingerprints of the iridoid glycosides fraction and the phenylethanol glycosides fraction, respectively. According to the calculation method for content determination, the quality control coefficient Q was introduced, and a mathematical model was established to evaluate the quality of Rehmanniae Radix based on the value of Q. With catalpol, rhmannioside D, and acteoside as reference peaks, the quality control coefficients Q_Z=0.17A_(total)/A_(min), Q_D=0.085A_(total)/A_(min), Q_M=0.017A_(total)/A_(min) were calculated. It was defined that the catalpol coefficient Q_Z≥0.57 or the rhmannioside D coefficient Q_D≥0.69 indicated that the iridoid glycosides fraction of the tested sample was qualified; the acteoside coefficient Q_M≥0.019 indicated that the phenylethanol glycosides fraction of the tested sample was qualified. Moreover, a high Q value suggested that the glycoside content was high. It is considered that the Q coefficient, in addition to reflecting the authenticity of the sample, serves as an indicator of the sample quality. According to the evaluation based on the quality control coefficient Q, it is suggested that the quality of Rehmanniae Radix is good within the storage period of 6 years, and the quality is better within a shorter storage period. Comparison of samples from the same year showed that the evaluation results obtained based on Q_Z, Q_D, and Q_M were generally consistent and parallel. The construction of the pharmacological activity-chemical component group structure relationships for iridoid glycosides and phenylethanoid glycosides in Rehmanniae Radix, aimed at intervening and regulating kidney-Yin deficiency, enables the successful establishment of the quality control coefficient Q. This methodology provides a reference for enhancing the quality assessment standards of other TCMs and their products.