Development of a three-step-based novel strategy integrating DMPK with network pharmacology and bioactivity evaluation for the discovery of Q-markers of traditional Chinese medicine prescriptions: Danlou tablet as an example

Background: Quality marker (Q-marker) serves an important role in promoting the standardization of the quality of traditional Chinese medicine (TCM) prescriptions. However, discovering comprehensive and representative Q-markers from TCM prescriptions composed of multiple components remains difficult. Purpose: A three-step-based novel strategy integrating drug metabolism and pharmacokinetics (DMPK) with network pharmacology and bioactivity evaluation was proposed to discover the Q-markers and applied to a research example of Danlou tablet (DLT), a famous TCM prescription with remarkable and reliable clinical effects for coronary heart disease (CHD). Methods: Firstly, the metabolic profile in vivo of DLT was systemically characterized, and the pharmacokinetic (PK) properties of PK markers were then investigated. Secondly, an integrated network of "PK markers - CHD targets - pathways - therapeutic effects" was established to screen out the crucial PK markers of DLT against CHD. Thirdly, the crucial PK markers that could exhibit strong myocardial protection activity in the H9c2 cardiomyocyte model were selected as the candidate Q-markers of DLT. According to the proportion of their C-max value in vivo, the candidate Q-markers were configured into a composition; the bioactivity was then evaluated to confirm their synergistic effect and justify their usage as Q-markers. Results: First of all, a total of 110 DLT-related xenobiotics (35 prototypes and 75 metabolites) were detected in bio-samples, and the pharmacokinetic properties of 13 PK markers of DLT were successfully characterized, revealing the quality transitivity and traceability from prescription to in vivo. Then, 6 crucial PK markers with three topological features (degree, betweenness, and closeness) greater than the average values in the pharmacology network were screened out as the key components of DLT against CHD. Furthermore, among these 6 crucial PK markers, 5 components (puerarin, alisol A, daidzein, paeoniflorin, and tanshinone IIA) with strong myocardial protection activity were chosen as the candidate Q-markers to constitute a new composition. The composition activated the expression of the PI3K/AKT pathway and exhibited strong myocardial protection activity, and the effective concentrations (nM level) of these components in the composition were significantly lower than their individually effective concentrations (uM level), indicating that there was a certain synergistic effect between them. Hence, the 5 components with multiple properties, including testability, quality transitivity and traceability from prescription to in vivo, effectiveness, and compatibility contribution, were defined as comprehensive and representative Q-markers of DLT. Conclusion: This study not only presented a novel idea for the revelation of comprehensive and representative Q-markers in quality control research of TCM prescriptions, but also identified the reasonable Q-markers of DLT for the first time to improve the quality control level of DLT.