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The purpose of this work was to study the influences of Realgar-Indigo naturalis(RIF) and its principal element realgar on 4 main cytochrome P450 enzymes activities in rats. A simple and efficient cocktail method was developed to detect the four probe drugs simultaneously. In this study, Wistar rats were administered intragastric RIF and realgar for 14 days; mixed probe drugs were injected into rats by caudal vein. Through analyzing the pharmacokinetic parameter of mixed probe drugs in rats, we can calculate the CYPs activities. The results showed that RIF could inhibit CYP1A2 enzyme activity and induce CYP2C11 enzyme activity significantly. Interestingly, in realgar high dosage group, CYP3A1/2 enzyme activity was inhibited significantly, and different dosage of realgar manifested a good dose-dependent manner. The RIF results indicated that drug coadministrated with RIF may need to be paid attention in relation to drug-drug interactions (DDIs). Realgar, a toxic traditional Chinese medicine (TCM), does have curative effect on acute promyelocytic leukemia (APL). Its toxicity studies should be focused on. We found that, in realgar high dosage group, CYP3A1/2 enzymes activity was inhibited. This phenomenon may explain its potential toxicity mechanism.

To investigate the effects of P. ginseng C.A. Mey (P. ginseng) on the metabolism of diester alkaloids and explore the potential mechanism. P. ginseng was administered orally to rats for 7 days, after which liver microsome samples were prepared and then incubated with diester alkaloids. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry was used to determinate the concentration of diester alkaloids to calculate the clearance rate. The cocktail method was used to evaluate the effects of oral administration of P. ginseng extracts on the activities of cytochrome P450 (CYP) isoforms in rats through the changes in the pharmacokinetic parameters of the probe drugs. The protein and gene expression of CYP3A2 and pregnane X receptor (PXR) in rats were evaluated by western blotting and quantitative PCR. The specific enzyme inhibitor method and human recombinant enzyme method were used to identify the involvement of sub-CYPs in the metabolism of diester alkaloids in human liver microsomes (HLMs). The clearances of aconitine, mesaconitine, and hypaconitine in the P. ginseng groups were lower than those of the control group. The areas under the curve of midazolam were 2.37 ± 1.05, 4.96 ± 0.51, and 6.23 ± 1.30 mg·L−1·h for the low-, medium-, and high-dose P. ginseng groups, respectively, which were higher than that of the control (2.23 ± 0.64 mg·L−1·h). The clearances of midazolam for the medium- (1.87 ± 0.16 L·h−1·kg−1) and high-dose (1.60 ± 0.34 L·h−1·kg−1) P. ginseng groups were lower than that of the control group (4.66 ± 1.43 L·h−1·kg−1). After exposure to P. ginseng extracts, the gene and protein expression levels of CYP3A4 and PXR were decreased. The hepatic metabolism rates of aconitine, mesaconitine, and hypaconitine in HLMs were decreased to 60.37%, 21.67%, and 10.11%, respectively, when incubated with ketoconazole, a specific inhibitor for CYP3A. The kinetic plots indicated that the KM and Vmax values of CYP3A4 were 10.08 ± 3.26 μM and 0.12 ± 0.01nmol·mg protein−1·min−1 for aconitine, 131.3 ± 99.75 μM and 0.73 ± 0.44 nmol·mg protein−1·min−1 for mesaconitine, and 17.05 ± 9.70 μM and 0.16 ± 0.04 nmol·mg protein−1·min−1 for hypaconitine, respectively. The in vitro mean intrinsic clearance rates by CYP3A4 were 0.0119, 0.0056, and 0.0091 mL·nmol CYP−1·min−1 for aconitine, mesaconitine, and hypaconitine, respectively. Therefore we implied that P. ginseng inhibited the metabolism of diester alkaloids in vitro and decreased the CYP3A4 enzyme activity as well as the gene and protein expression of CYP3A4 and PXR in vivo. CYP3A4 had a larger effect on diester alkaloid metabolism than the other human CYP isoforms, CYP1A2, CYP2C9, and CYP2E1.

Xianxie Zhang,1 Yuguang Wang,2 Zengchun Ma,2 Qiande Liang,2 Xianglin Tang,2 Donghua Hu,2 Hongling Tan,2 Chengrong Xiao,2 Yue Gao2 1Air Force General Hospital of People’s Liberation Army, Beijing, People’s Republic of China; 2Department of Pharmacology and Toxicology, Beijing Institute of Radiation Medicine, Beijing, People’s Republic of China Abstract: Tanshinone IIA (Tan IIA) (C19H18O3) is one of the major active lipophilic components in a conventional Chinese medicine called danshen, and it has long been used in the People’s Republic of China and other neighboring countries to treat patients suffering from inflammatory bowel disease (IBD). Previous experiments by many teams determined which mechanism of Tan IIA is relevant to the treatment of IBD associated with inflammation and the pregnane X receptor (PXR). The current study demonstrated that Tan IIA is an efficacious PXR agonist and its ability to induce CYP3A4 mRNA and protein expression was mediated by the transactivation of PXR, a known target of abrogating inflammation in IBD. Clinical symptoms in mice and histological assessment data suggested that administration of Tan IIA in mice demonstrated significant protection and showed that in DSS-induced IBD it acts in a concentration-dependent manner. PXR-silenced mice treated with Tan IIA demonstrated low protection against DSS-induced mouse IBD and exacerbated the severity of IBD compared with wild-type mice; PXR-silenced mice demonstrated the necessity for PXR in Tan IIA-mediated upregulation of xenobiotic metabolism genes. The IBD treatment effects of Tan IIA are partially due to PXR-mediated upregulation of xenobiotic metabolism and downregulation of inflammatory mediators. The novel findings reported here may contribute to the effective utilization of Tan IIA and its derivatives as a PXR ligand in the treatment of human IBD. This suggests that Tan IIA may have considerable clinical utility. Keywords: dashen, ulcerative colitis, Crohn’s disease, tanshinone IIA, pregnane X receptor, inflammatory bowel disease, dextran sodium sulfate

The eighteen incompatible medicaments is an important theory in traditional Chinese medicine. The theory suggests that drugs in the eighteen incompatible medicaments can be toxic when used together.Veratrum nigrumL. andRadix paeoniae albabelong to the eighteen incompatible medicaments and have been prohibited for thousands of years. This study offers preliminary insight into the mechanism and chemical constituents responsible for the incompatibility and toxicity of these two agents. Specifically, we performed toxicology studies to identify and quantify the constituent substances of the two agents. Experiments revealed that acute toxicity increases when the dose ofV. nigrumL. is higher than, or equal to, RPA. UPLC-TOF-MS analysis showed that, although the volumes ofV. nigrumL. were the same, the content of some veratrum alkaloids changed significantly and had a trend toward a highly positive correlationr≥0.8with toxicity. This suggests that the increased toxicity of theV. nigrumL. and RPA combination was due mainly to increased content of the special veratrum alkaloids. The cytotoxicity of veratridine in SH-SY5Y cells was decreased with increasing paeoniflorin concentrations. This study provides insight into the mechanism behind the incompatibility theory of TCM.

In the present study, an ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOFMS) based chemical profiling approach to rapidly evaluate chemical diversity after co-decocting of the incompatible pairs of Veratrum nigrum and radix ginseng. Result showed significant difference between two kinds of decoction samples, and Veratrum steroid alkaloids (VSAs), eg. jervine, pseudojervine, rubijervine, deoxyjervine, angeloylzygadenine, veratroylzygadenine, veratridine were identified as the most changed/increased toxic components of the incompatible pairs of Veratrum nigrum during co-decocting.

Combined research on prescriptions and zheng hou sets up a bridge between theory and therapy in traditional Chinese medicine (TCM). Based on Si wu tang (SWT) and blood deficiency (BD), three BD animal models were induced by 60Co irradiation, cyclophospha- mide, or chronic bleeding. Factors such as circulating blood cells, the ability of colony-forming unit of bone marrow cells, CD34+ count, cell cycle, and apoptosis play important roles in the pathogenesis and development of BD. Based on pharmacology mechanism research on the entire body, tissue, cell and molecular level, polysaccharide, paeoniflorin, tetramethylpyrazine, and ferulic acid were found to be hematopoietic constituents of SWT. And hematopoietic cytokines are also involved in hematopoietic mechanism of SWT.