A quantifiable grading standard for Codonopsis Radix based on the multidimensional quality evaluation system of phenotype, chemistry, and bioactivity.

As a medicinal and edible herb, the quality grade of Codonopsis Radix (CR) is the key determinant of its market price. However, the current grading system remains significantly inadequate. Single-dimensional indices (including phenotypic traits, chemical components, or bioactivity) fail to accurately characterize the comprehensive quality of CR. Under this circumstance, this study established a multidimensional quality evaluation system integrating phenotypic traits, chemical components, and bioactivity. A multi-index weighted quality comprehensive evaluation index (QCEI) was constructed by combining the entropy weight method (EWM), criteria importance through inter-criteria correlation (CRITIC) method, technique for order preference by similarity to ideal solution (TOPSIS) method, and triangular area method. Hierarchical cluster analysis (HCA) based on QCEI classified 50 CR batches into 3 grades: Grade I (QCEI≥0.56, excellent quality), Grade II (0.38 ≤ QCEI<0.56, good quality), and Grade III (QCEI<0.38, general quality). In vivo validation showed a significant positive correlation between QCEI grades and immunomodulatory effects. Specifically, the CR of Grade I significantly enhanced the body weight growth rate, elevated thymus and spleen indices, and regulated serum levels of IL-2, IL-6, and TNF-α in immunosuppressed mice (p < 0.05-p < 0.0001). This study establishes a scientific and reliable quality grading standard for CR, providing a valuable reference for the comprehensive quality evaluation of other traditional Chinese medicinal materials.