An integrated chromatographic fingerprinting strategy for quality evaluation and Q marker screening based on the bi...

To address the persistent challenges of quality consistency and efficacy stability in traditional Chinese medicine preparations arising from variations in raw materials and manufacturing processes, and the inability of conventional quality control approaches to directly link overall chemical characteristics with bioactivity, this study aimed to develop a function-oriented quality evaluation system and a new pathway for activity-relevant Q-marker screening. Using Xuezhikang capsules (XZK) as a model, high performance liquid chromatography (HPLC) fingerprints and electrochemical fingerprints were constructed for 30 batches of samples, and the Bi Value Method based on macro qualitative similarity (S_m) and macro quantitative similarity (P_m) was applied for qualitative identification and quantitative grading. A novel peak separation information energy index (P_RI) was proposed to characterize chromatographic separation performance and information integrity. Antioxidant activity was evaluated using DPPH radical scavenging and Belousov-Zhabotinsky (B-Z) oscillation inhibition assays, and the relationships between fingerprint features and bioactivity were analyzed via partial least squares (PLS) modeling. The results showed that all samples exhibited high chemical similarity (S_m > 0.996), while P_m enabled classification into three quality grades and was highly correlated with total peak area. P_RI demonstrated good reproducibility and complemented P_m in quality monitoring. Electrochemical fingerprints revealed more refined functional differences, further differentiating samples into five grades. PLS analysis and P_m-activity coupling consistently identified G1, G3, G4, G8, and G17 as key antioxidant-related Q-marker candidates. Overall, this integrated framework combining chromatographic profiling, electrochemical behavior, P_RI evaluation, and bioactivity modeling provides a reliable, function-oriented strategy for quality grading and Q-marker discovery in traditional medicines.