Identification of urine tauro-ß-muricholic acid as a promising biomarker in Polygoni Multiflori Radix-induced hepatotoxicity by targeted metabolomics of bile acids.

Polygoni Multiflori Radix (PMR) has been widely used as a tonic for centuries. However, hepatotoxicity cases linked to PMR have been frequently reported and appropriate biomarkers for clinical diagnosis are currently lacking. Here, an approach using UPLC-QqQ/MS-based targeted metabolomics of bile acids (BAs) complemented with biochemistry and histopathology was applied to characterize the development and recovery processes of PMR-induced hepatotoxicity in rats and to identify biomarkers. The expression of bile salt export pump (Bsep) and sodium taurocholate cotransporting polypeptide (Ntcp) were evaluated to investigate the underlying mechanism. Steatosis and inflammatory cell infiltration were observed in PMR-treated rats, which were accompanied by the elevation of serum biochemistry. The metabolic profiles of BAs were analyzed by Principal Component Analysis, hyodeoxycholic acid (HDCA) in serum and tauro-ß-muricholic acid (TßMCA) in urine were identified as potential biomarkers for PMR-induced hepatotoxicity. The elevated expression of Bsep and decreased expression of Ntcp in the liver of PMRtreated rats indicated that hepatotoxicity was related to the disorders of BAs metabolism. Our study demonstrated that BAs may be used for clinical diagnosis of PMR-induced hepatotoxicity. Urine TßMCA was identified as a promising biomarker to facilitate the clinical monitoring of PMR-induced hepatotoxicity and may serve as potential therapeutic target.

Synergistic effects of rhubarb-gardenia herb pair in cholestatic rats at pharmacodynamic and pharmacokinetic levels.

ETHNOPHARMACOLOGICAL RELEVANCE: Herb pair serves as the basic building block of a traditional Chinese medicine (TCM) formula. The rhubarb-gardenia herb pair (RGHP), composed of rhubarb and gardenia, has meaningful clinical effects to cure cholestasis diseases. This study was designed to confirm the expected synergistic effects of RGHP at pharmacodynamic and pharmacokinetic levels. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were divided into control, model and drug-treated groups. After intragastrically administrated with α-naphthylisothiocyanate (ANIT) to induce cholestasis, rats were treated with rhubarb, gardenia or RGHP. For pharmacodynamic study, biochemical and histopathological tests were performed to assess the hepatoprotective effects. While for pharmacokinetic study, a LC-MS method was developed for determination of five main chemical markers, namely genipin, rhein, aloe emodin, emodin and chrysophanol in rat plasma. RESULTS: The biochemical and histopathological tests suggested that RGHP exerted enhanced hepatoprotective effects against the ANIT-induced cholestasis compared with single herbs. The pharmacokinetic study indicated RGHP could significantly elevate systemic exposure level and prolong retention time of five markers in comparison with rhubarb or gardenia alone. CONCLUSIONS: The present study demonstrated the synergistic effects of RGHP in ANIT-induced cholestatic rats at pharmacodynamic and pharmacokinetic levels, and has significant enlightenments for the rational use of the related TCM formulas containing RGHP.

The integrated pharmacokinetics of major rhodojaponins correlates with the cardiotoxicity after oral administration of Rhododendri Mollis Flos extract in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhododendri Mollis Flos (RMF), termed as Naoyanghua in Chinese, is a traditional anti-rheumatoid arthritis and bruises herb with associated cardiotoxicity. The predominant rhodojaponins occurring in RMF are responsible for its efficacy and toxicity. The narrow therapeutic window of rhodojaponins necessitates monitoring the pharmacokinetics and pharmacodynamics so as to ensure the safety in practical applications of RMF. MATERIALS AND METHODS: Fifty-four male Sprague-Dawley rats were divided into a control group, a low-dose group and a high-dose group. After oral administration of RMF extract, the cardiotoxicity of RMF was evaluated by assessing ventricular function and by measuring the plasma levels of LDH, CK-MB and AST. Then, an LC-MS method was established to determine the rat plasma concentrations of three major rhodojaponins including rhodojaponin I, II and III (R-I, II and III) and was applied to pharmacokinetic study. Finally, based on an AUC-weighting approach, the integrated pharmacokinetics of three rhodojaponins was determined. RESULTS: Compared with control group, cardiotoxicity was observed in RMF-treated rats with left ventricular dysfunction and with the continuously increased levels of LDH and CK-MB in a dose-dependent manner. The pharmacokinetic parameters (AUC0-t, AUC0-∞, t1/2, Tmax and Cmax) for R-I, II and III were markedly different, and the integrated pharmacokinetics was therefore converted to describe the holistic pharmacokinetic profiles of R-I, II and III, which correlated pretty well with cardiotoxicity. CONCLUSIONS: It was found that myocardial damage was elicited by RMF extract in a dose-dependent manner and the plasma levels of LDH and CK-MB could reveal the severity of myocardial injury as potential markers. This study also highlighted the potential of integrated pharmacokinetics to provid a more comprehensive understanding of the relationship between the pharmacokinetic behaviors of traditional Chinese herbal medicine and its efficacy.