Impact of Herbal Medicines like Nigella sativa, Trigonella foenum-graecum, and Ferula asafoetida, on Cytochrome P450 2C11 Gene Expression in Rat Liver.

AIM: Combined use of herbs and drugs may result in clinically important herb-drug interactions. The majorities of these interactions are thought to be metabolism-based and involve induction or inhibition of cytochrome P450 (CYP). The current study was designed to investigate the effect of some commonly used herbs on rat CYP2C11 gene expression and metabolic activity. METHODS: Wistar rats were treated for 7 days with increasing doses of 3 herbs; Nigella sativa, Trigonella foenum-graecum, and Ferula asafoetida. Thereafter, CYP2C11 mRNA and protein levels were determined by real-time polymerase chain reaction (RT-PCR) and western blot analyses, respectively. In vitro metabolic activity of CYP2C11 was performed on rat hepatic microsomes using tolbutamide as specific substrate. RESULTS: Our results showed that all the 3 herbs significantly inhibited the mRNA and protein expression levels of CYP2C11 in a dose-dependent manner. Furthermore, the in vitro enzyme metabolic activity study showed a significant decrease in the formation of 4-hyroxy-tolbutamide, a tolbutamide metabolite, at the higher doses. The inhibitory effects of the investigated herbs on rat CYP2C11 was in the order: Nigella Sativa > Trigonella foenum-graecum > Ferula asafoetida. CONCLUSIONS: The 3 herbs are strong inhibitor of CYP2C11 expression, which can lead to an undesirable pharmacological effect of clinically used CYP2C11 substrate drugs with a low therapeutic index.

Renal expression of arachidonic acid metabolizing enzymes and RhoA/Rho kinases in fructose insulin resistant hypertensive rats.

Fructose feeding has been shown to induce insulin resistance and hypertension. Renal protein expression for the cytochrome P (CYP) 450 arachidonic acid metabolizing enzymes has been shown to be altered in other models of diet-induced hypertension. Of special interest is CYP4A, which produces the potent vasoconstrictor, 20-hydroxyeicosatetraenoic acid and CYP2C, which catalyzes the formation of the potent dilators epoxyeicosatrienoic acids as well as soluble epoxide hydrolase (sEH) which metabolizes the latter to dihydroxyeicosatrienoic acids. The RhoA/Rho kinase (ROCK) signaling pathway is downstream of arachidonic acid and is reported to mediate metabolic-cardio-renal dysfunctions in some experimental models of insulin resistance and diabetes. The aim of the present study was to determine the expression of CYP4A, CYP2C23, CYP2C11, sEH, RhoA, ROCK-1, ROCK-2, and phospho-Lin-11/Isl-1/Mec-3 kinase (LIMK) in kidneys of fructose-fed (F) rats. Male Wistar rats were fed a high fructose diet for 8 weeks. Body weight, systolic blood pressure, insulin sensitivity, and renal expression of the aforementioned proteins were assessed. No change was observed in the body weight of F rats; however, euglycemia and hyperinsulinemia implicating impaired glucose tolerance and significant elevation in systolic blood pressure were observed. Renal expression of CYP4A and CYP2C23 was significantly increased while that of CYP2C11 and sEH was not changed in F rats. Equal expression for RhoA in both control and F rats and an enhanced level of ROCK-1 and ROCK-2 constitutively activate 130 kDa cleavage fragments as well as phospho-LIMK. These data suggest that the kidneys could be actively participating in the pathogenesis of insulin resistance-induced hypertension through the arachidonic acid CYP 450-RhoA/Rho kinase pathway(s).

Changes of midazolam pharmacokinetics in Wistar rats treated with lipopolysaccharide: relationship between total CYP and CYP3A2.

It has been reported that infection interferes with drug metabolism, resulting in changes in pharmacokinetics. In this study, we investigated the effects of lipopolysaccharide (LPS) on hepatic total cytochrome P450 (CYP), CYP3A2, and CYP2C11 contents in a transient, LPS-induced, endotoxemia model of rats. In addition, to assess the effects on CYP3A2 activities, the pharmacokinetics of midazolam (CYP3A2 substrate) and 1-OH-midazolam (metabolite of midazolam) were investigated. Hepatic total CYP contents were significantly low until day 3 (P < 0.05) but returned to the control level on day 5. Hepatic CYP3A2 contents were significantly decreased on day 1 until day 5 (P < 0.05) but returned to the control level on day 7. Hepatic CYP2C11 contents were continuously low until day 7, and lowest on day 3. The AUC of 1-OH-midazolam was significantly decreased on day 1 after LPS administration (P < 0.01). In conclusion, LPS (5 mg/kg) challenge decreased hepatic total CYP, CYP3A2, and CYP2C11 contents and also decreased the activities of hepatic CYP3A2. It took at least 7 days for hepatic total CYP and CYP3A2 to recover to control levels, and it was suggested that the changes of hepatic total CYP contents might correlate with those of hepatic CYP3A2 contents and activities. Additionally, it is shown that their changes might reflect the recovery process from inflammation.

Altered kidney CYP2C and cyclooxygenase-2 levels are associated with obesity-related albuminuria.

OBJECTIVE: To determine cytochrome P450 (CYP450) and cyclooxygenase (COX) expression and metabolite regulation and renal damage in the early stages of obesity-related hypertension and diabetes. RESEARCH METHODS AND PROCEDURES: Obese and lean Zucker rats at 10 to 12 weeks of age were studied. Blood pressure was measured in the conscious state using radiotelemetry. Blood glucose levels and body weight were measured periodically. Protein expression of CYP450 and COX enzymes in the kidney cortex, renal microvessels, and glomeruli was studied. The levels of CYP450 and COX metabolites in urine were measured, and urinary albumin excretion, an indicator of kidney damage, was measured. RESULTS: Body weight and blood glucose averaged 432 +/- 20 grams and 105 +/- 5 mg/dl, respectively, in obese Zucker rats as compared with 320 +/- 8 grams and 91 +/- 5 mg/dl, respectively, in age-matched 10- to 12-week-old lean Zucker rats. Renal microvascular CYP4A and COX-2 protein levels were increased 2.3- and 17.0-fold, respectively, in obese Zucker rats. The protein expression of CYP2C11 and CYP2C23 was decreased 2.0-fold in renal microvessels isolated from obese Zucker rats when compared with lean Zucker rats. The urinary excretion rate of thromboxane B(2) was increased significantly in obese Zucker as compared with lean Zucker rats (22.0 +/- 1.8 vs. 13.4 +/- 1.0 ng/d). Urinary albumin excretion, an index of kidney damage, was increased in the obese Zucker rat at this early age. DISCUSSION: These results suggest that increased CYP4A and COX-2 protein levels and decreased CYP2C11 and CYP2C23 protein levels occur in association with microalbuminuria during the onset of obesity-related hypertension and type 2 diabetes.

Differential expression of cytochrome P450 isoforms in the lungs of septic animals.

OBJECTIVE: Sepsis is characterized by an early, hyperdynamic phase and a late, hypodynamic phase. Although studies have shown that cytochrome P450 (CYP) plays an important role in the regulation of vascular reactivity, alterations of vascular CYP isoforms in sepsis remain unknown. Since CYP2C11 and CYP2J4 convert arachidonic acid to vasodilative epoxyeicosatrienoic acids, and CYP4A3 metabolizes arachidonic acid to both epoxyeicosatrienoic acids and vasoconstrictive 19,20-hydroxyeicosatetraenoic acid, the aim of this study was to examine the expression of these isoforms in sepsis and their association with hemodynamic changes. DESIGN: Prospective, controlled, and randomized animal study. SETTING: An institute research laboratory. SUBJECTS: Male adult Sprague-Dawley rats were subjected either to polymicrobial sepsis by cecal ligation and puncture or to sham operation followed by the administration of normal saline solution (i.e., fluid resuscitation). INTERVENTIONS: At 5 hrs (early sepsis) or 20 hrs (late sepsis) after cecal ligation and puncture, blood vessel-rich tissues (i.e., lungs) were harvested. The expression of CYP isoforms at both messenger RNA and protein levels was determined by reverse transcription polymerase chain reaction and Western blot analysis (CYP2C11), respectively. Hemodynamic variables were measured by radioactive microspheres. MAIN RESULTS: The results indicate that the gene expression of CYP2C11 and CYP2J4 was significantly down-regulated at 20 hrs after cecal ligation and puncture, whereas the expression of CYP4A3 was markedly up-regulated at 5 hrs. The protein concentrations of CYP2C11 also decreased significantly at 20 hrs after cecal ligation and puncture. Although total peripheral resistance markedly increased, mean arterial pressure did not change significantly at 20 hrs after the onset of sepsis. In contrast, cardiac output and pulmonary perfusion markedly decreased in late sepsis. CONCLUSIONS: Since the up-regulated CYP4A3 is associated with the early, hyperdynamic phase of sepsis and the down-regulated CYP2C11 and CYP2J4 are associated with the late, hypodynamic phase, vascular CYP isoforms that metabolize arachidonic acid may be involved in regulating the cardiovascular response during the progression of sepsis.