Influence of Zhuanggu Guanjie Pill on Seven Cytochrome P450 Enzymes Based on Probe Cocktail and Pharmacokinetics Approaches.

BACKGROUND: The use of herbal medicines has tremendously increased over the past few decades. Case reports and controlled clinical investigations of herbal-drug interactions have been reported. Since Cytochrome P450 (CYP) enzymes play an important role in drug interactions. The evaluation of the influence of herbal medicines on the activities of CYPs is beneficial to promote scientific and rational clinical use of herbal medicines. OBJECTIVE: Herein, we aimed to develop and validate a method to simultaneously quantify seven CYP cocktail probe drugs consisting of phenacetin (PNC), bupropion (BPP), losartan potassium (LK), omeprazole (OMP), dextromethorphan (DM), chlorzoxazone (CZZ) and midazolam (MDZ) and their respective metabolites in a single acquisition run and use this method to evaluate the influence of Zhuanggu Guanjie Pill (ZGGJP) on seven CYPs. METHODS: A cost-effective and simple UHPLC-(±)ESI-MS/MS method for simultaneous determination of seven probe drugs and metabolites in rat plasma was developed and validated. Male and female rats were randomly divided into three groups and treated with 1.2 g/kg/d ZGGJP, 5 g/kg/d ZGGJP and 0.5% CMC-Na for 14 consecutive days. After 24 h of the last administration, all rats were administrated orally with probe drugs. The influence of ZGGJP on the CYPs was carried out by comparing the metabolic ratio (Cmax, AUC0-t) of metabolites/probe drugs in rats. RESULTS: The calibration curves were linear, with correlation coefficient > 0.99 for seven probe drugs and their corresponding metabolites. Intra- and inter-day precisions were not greater than 15% RSD and the accuracies were within ±15% of nominal concentrations. The ZGGJP showed significant inductive effect on CYP1A2, CYP2B6, CYP2C9 and CYP3A in male and female rats. CONCLUSION: ZGGJP had inductive effects on CYP1A2, CYP2B6, CYP2C9 and CYP3A in male and female rats.

[Determination of concentrations and toxicokinetics of triptolide in plasma and liver of mice by UHPLC-MS/MS].

This study aims to establish an ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS) method for determining the concentrations of triptolide(TP) in plasma and liver, and to explore the toxicokinetics of TP and the relationship between TP exposure and liver injury in C57 BL/6 mice, so as to provide reference for dissecting the toxicity mechanism of TP. The liquid chromatography was conducted with ZORBAX SB-C_(18) column(3.0 mm×100 mm, 3.5 µm) and the mobile phase of methanol-0.05 mmol·L~(-1) ammonium acetate. Electrospray ionization(ESI) and multiple reaction monitoring(MRM) mode were employed for mass spectrometry. After oral administration of TP(toxic dose 600 µg·kg~(-1)), the blood and liver tissues of the C57 BL/6 mice were collected at different time points to measure the TP concentrations in plasma and liver tissues. Furthermore, the blood biochemical indexes, including alkaline phosphatase(ALP), alanine aminotransferase(ALT), aspartate aminotransferase(AST), and total bile acid(TBA), were determined. After being processed by DAS 2.0, the experiment data showed that the TP in mice had the toxicokinetic parameters of T_(max)=5 min, C_(max)=14.38 ng·mL~(-1), t_(1/2)=0.76 h, AUC_(0-t)=5.63 h·ng·mL~(-1), MRT_(0-t)=0.56 h, and CL_(Z/F)=103.19 L·h~(-1)·kg~(-1). The trend of TP concentration in mouse liver tissue was consistent with that in plasma. The concentration of TP peaked at the time point of 5 min and then decreased until TP was completely metabolized. The plasma biochemical indexes(ALT, AST, ALP, and TBA) showed no significant changes within 3 h after TP administration. TP had high clearance rate and short residence time and did not significantly increase the blood biochemical indexes in mice. The results suggested that the exposure amount of free TP in vivo cannot directly cause liver injury, which might be caused by the binding of TP to some substances or the stimulation of inflammation and immune response.

Antioxidant Activities of Stilbenoids from Rheum emodi Wall.

Rheum emodi Wall has been reported to possess protective effect in many inflammatory diseases and oxidative stress-related injuries. This study aims to investigate antioxidant power of stilbenoids from R. emodi and then explore the material basis for its antioxidant potential. The most abundant stilbenoid piceatannol-4'-O-ß-D-glucopyranoside (PICG) and its aglycon piceatannol (PICE) were isolated from R. emodi rhizome. Using well-accepted antioxidant chemicals as reference, antioxidant activity of these stilbenoids was examined by measuring DPPH and superoxide anion radical scavenging, ferric reducing power, and inhibition of lipid peroxidation in vitro. Both PICG and PICE displayed promising antioxidant activity in all the four assays. Comparisons among the tested compounds indicated that PICE has the most potent antioxidant activity and the presence of 3'-hydroxyl group may enhance antioxidant activity of stilbenoids. The antioxidative effect of PICE at the cellular level was further demonstrated on the model of hydrogen-peroxide-induced H9c2 rat cardiomyoblasts injury. Taking into account the rapid in vivo metabolic transformation of PICG into PICE it can be inferred that the most abundant stilbenoid PICG may be an important constituent responsible for the antioxidant potential of R. emodi and promising to be developed as an antioxidant agent for supplementary or therapeutic use.