Beyond chemistry: A multidimensional approach to assessing Cortex fraxini

• We formulated an ECI to assess the antioxidant properties of Cortex fraxini . • Cortex fraxini samples with high, medium, and low ECIs were selected for analysis. • This novel approach can bridge herbal quality with therapeutic efficacy. • It augments the quality assessment framework for herbal medicines. Traditional chemical analysis methods for evaluating the quality of traditional Chinese medicine (TCM), such as Cortex Fraxini (C. Fraxini), often fail to comprehensively address spectrum–effect, dose–effect, and toxicity–effect relationships, limiting their ability to predict clinical efficacy and safety. To overcome this challenge, this study introduces the effect–constituent index (ECI), a novel metric integrating multidimensional chemical composition data and bioactivity-based weighting strategies for holistic quality assessment. Focusing on the antioxidant properties of C. Fraxini, we established a high-performance liquid chromatography (HPLC) fingerprint profile to quantify four key bioactive components (esculin, fraxin, esculetin, and fraxetin) and evaluated their antioxidant capacities via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging assays. The ECI framework revealed significant variability in antioxidant potential across 38 batches, with batches S13, S16, and S11 exhibiting the highest DPPH- and ABTS-based ECI values, while S10, S35, and S14 consistently ranked lowest. Validation experiments confirmed a strong correlation between calculated ECI values and experimentally determined antioxidant activities, although certain batches (e.g., S11, S13, S15, S16) demonstrated higher measured bioactivity than predicted. This study successfully bridges chemical composition with therapeutic efficacy by establishing concentration–effect relationships for active constituents, offering a robust and innovative tool for advancing quality control paradigms in herbal medicine. The ECI model provides a scientific foundation for optimizing the safety, efficacy, and standardization of TCM.