Experimental Adjustment on Drug Interactions through Intestinal CYP3A Activity in Rat: Impacts of Kampo Medicines Repeat Administered

Abstract

To provide the information that is necessary for making the proper use of kampo medicines, we have proposed the adequate methodology focused on the following issues: (i) kampo medicines emphasize the effects produced by the combination of herbal drugs rather than the individual effect of any single herb and (ii) Intestinal CYP3A has become a key factor for the bioavailability of orally administrated drugs. In the present study, we investigated both the in vivo and in vitro effects of Saireito and Hochuekkito (kampo formulas) on CYP3A activities. From our study, oral pre-treatment with Saireito or Hochuekkito did not affect the pharmacokinetics of nifedipine after intravenous administration to rats. When nifedipine was administered to rat intrajejunum, a significant decrease of AUC was showed by pre-treatment with both kampo formulas. Saireito pre-treatment led to 80% decrease in C max of nifedipine. Saireito caused significant increases in both protein expression and metabolic activity of CYP3A in intestinal microsome, whereas it had no effect on CYP3A in hepatic microsome. Our result also showed that this affect of Saireito can be gone by wash-out with 1 week. These findings demonstrated that Saireito may induce CYP3A activity of intestine but not of liver in rats. When resources for research are limited, well-designed scientific studies except clinical trials also have many advantages.

Extracts of Immature Orange (Aurantii fructus immaturus) and Citrus Unshiu Peel (Citri unshiu pericarpium) Induce P-Glycoprotein and Cytochrome P450 3A4 Expression via Upregulation of Pregnane X Receptor

“…We examined changes in intracellular drug concentration using LS180 cells, which are a suitable intestinal epithelial cell model to analyze interactions between drugs and epithelial cells ( Gupta et al, 2008 ; Lau et al, 2013 ), although in vivo studies are needed to confirm our findings. A previous study demonstrated that hochuekki-to containing CP increased CYP3A4 expression in the intestine and decreased the area under the curve for the CYP3A4 substrate nifedipine ( Kinoshita et al, 2011 ). This indicated that that induction of P-gp and CYP3A4 protein via upregulation of PXR in intestinal epithelial cells may occur in vivo .…”

“…Immature orange [ Aurantii fructus immaturus (IO)] and citrus unshiu peel [ Citri unshiu pericarpium (CP)] are common ingredients of kampo that are reported to have anti-hypercholesterolemic or orexigenic effects ( Yoshie et al, 2004 ; Hayakawa et al, 2014 ). However, a previous study reported that kampo containing IO or CP decreased the blood concentration of concomitantly administered CYP3A4 substrates via upregulation of CYP3A4 although the mechanism was unclear ( Kinoshita et al, 2011 ). IO and CP include some flavonoids that have pharmacological effects ( Tokunaga et al, 2016 ).…”

Baicalin pharmacokinetic profile of absorption process using novel in-vitro model: cytochrome P450 3A4-induced Caco-2 cell monolayers combined with rat intestinal rinse fluids

“…Rat intestine microsomes were prepared as described in our previous report . CYP3A enzyme activity was assessed according to 6β‐OH testosterone formation and which was measured using HPLC previously reported .…”

“…Rat intestine proteins were isolated and Western blot analysis was conducted to evaluate CYP3A protein levels according to previous methods . In brief, proteins (12 μg) from total cell lysates were separated using SDS‐PAGE and transferred onto polyvinylidene difluoride membranes.…”

“…Rat intestine microsomes were prepared as described in our previous report. [19] CYP3A enzyme activity was assessed according to 6β-OH testosterone formation and which was measured using HPLC previously reported. [16] The incubation mixture (final volume 0.5 ml) contained intestinal microsomes suspension (0.5 mg protein), 5 mm MgCl2, 100 mm sodium phosphate buffer (pH 7.4) and testosterone solution.…”