Effect of borneol on cytochrome P450 3A enzyme and midazolam pharmacokinetics in rats.

Borneol is a commonly used herbal medication in China and Japan. Previous studies have indicated that borneol could reduce the plasma concentrations of oneself and concomitant drugs, and its first-pass metabolism could be catalyzed by the cytochrome P450 3A (CYP3A) enzyme as well. The impact of borneol on CYP3A activity and efficacy in influencing the pharmacokinetics of co-administrated drugs is currently unknown. Therefore, the purpose of the current study is to investigate the effect of borneol on CYP3A enzyme in vivo. After treatment with borneol twice daily for 3 days, rat liver microsomes were exposed to probe substrates to determine CYP3A enzyme activity, protein, and RNA harvested using microsomal testosterone 6ß-hydroxylation as a marker of enzyme activity. To verify the result, the effect of borneol on the pharmacokinetics of the CYP3A model substrate midazolam was further examined. The results showed that borneol treatment had increased CYP3A expression at the mRNA, protein, and activity (testosterone 6ß hydroxylase activity) level in rat liver microsomes. In addition, borneol accelerated the metabolism of midazolam, which was consistent with the enhancement in CYP3A metabolic capacity. The hepatic clearance (Cl) of midazolam injected via the caudal vein in rats following borneol co-administration was higher; however, the area under the curve (AUC0-∞) was lower than the solvent. Hence, it was proposed that borneol could increase the metabolic activity of the CYP3A enzyme, which might cause drug-drug interactions in humans when using Chinese herbal or Western medicine with borneol.

[The anti-portal hypertension effect of oleanolic acid in CCl4-induced cirrhosis rats].

OBJECTIVE: To study the anti-portal hypertension effect of oleanolic acid (OA) in CCl4-induced cirrhosis rats and its mechanism. METHODS: Rats were induced to portal hypertension by CCl4. After treatment with low dose of OA (30 mg/kg) and high dose of OA (60 mg/kg) by intragastrically for a month, the parameters in serum or liver tissue including ALT, AST, MDA, GSH-Px, NOx, eNOS, cGMP and type I collagen were measured. The MAP, PP and HR were determined by hameodynamic method and the eNOS expression in liver was measured by western blot. The pathological changes of liver tissue were also tested by Masson dye. The normal group and model group were given 0.25% of CMC-Na solution. RESULTS: Compared with the model group, treatment with 30 mg/kg and 60 mg/kg OA significantly decreased the levels of ALT, AST, ALP, gamma-GT and MDA and enhanced the level of GSH-Px in liver (P<0.05). Moreover, the collagen content also notably lowered in CCl4-induced cirrhosis rats, thus decreasing the portal pressure (PP). However, the MAP and HR were not affected by OA treatment. In addition, the expression of eNOS in liver markedly increased after one mouth treatment of OA, hereof enhancing the level of cGMP and NOx in the CCl4-induced portal hypertensive rats (P<0.05). CONCLUSION: OA could inhibit the progress of fibrosis and lower the PP in CCl4-induced portal hypertensive rats and the anti-portal hypertension effect might be related to increasing the expression of eNOS and enhance the NOx level in liver.

[Anticoagulative effect and antiplatelet aggregation effect of combination of Hirudo and Tabanus on rat model of blood stasis syndrome].

OBJECTIVE: To observe anticoagulative effect and antiplatelet aggregation effect of the combination of Hirudo and Tabanus with different dose-ratio on rat model of blood stasis syndrome. METHODS: The rat model of blood stasis syndrome was established by subcutaneous injection of adrenaline combined with stimulation of icy water. Then prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) contents and inhibition rate of blood platelet aggregation were determined. RESULTS: Platelet aggregation increases, APTT and PT reduced, and FIB contents increased in model control group significantly (P<0.001). Hirudo, Tabanus and the combination of Hirudo and Tabanus had antiplatelet aggregation effect in varying degrees. APTT and PT were prolonged significantly (P<0.05 and P<0.01, respectively) in Hirudo group, Tabanus group and combination groups, especially in the group with dose-ratio of Hirudo to Tabanus being 4:3. FIB contents decreased significantly in combination group with dose-ratio being 3:1 (P<0.05). CONCLUSIONS: The combination groups of Hirudo and Tabanus have better effect of anticoagulation and antiplatelet aggregation than Hirudo group and Tabanus group. While in the four combination groups, the group recommended by classical TCM monograph with dose-ratio of Hirudo to Tabanus being 4:3, has the best anticoagulation effect.

[Effects of Rhizoma zingiberis and Pericarpium citri reticulatae extracts on myocardial ischemia in rats].

OBJECTIVE: To observe the effects of Rhizoma Zingiberis and Pericarpium Citri Reticulatae extracts on acute myocardial ischemia rats and explore the mechanism. METHODS: The model of myocardial ischemia in rats was established by ligating the front descending anterior branch of the coronary artery. With Fufang Danshen Pill as positive control drug,the effects of Rhizoma Zingiberis and Pericarpium Citri Reticulatae extracts on the electrocardiogram (ECG), the extension of myocardial infarction, the hemorheology indexes, lactic dehydrogenase (LDH), creatine kinase (CK), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in rats were evaluated. RESULTS: Rhizoma Zingiberis and Pericarpium Citri Reticulatae extracts decreased the ST-segment of ECG (P < 0.01), reduced the extension of myocardial infarction (P < 0.05), decreased the contents of CK and LDH in serum (P < 0.01 or P < 0.05), improved hemorheology (P < 0.05), increased SOD and GSH-Px activity and decreased MDA content (P < 0.05). CONCLUSION: Rhizoma Zingiberis and Pericarpium Citri Reticulatae extracts have protective effect on myocardial ischemia in rats, and its mechanism may be related to inhibiting lipid peroxidation.

[Effect of Wuling Powder on rats with renal hypertension].

OBJECTIVE: To observe the therapeutic effect of Wuling Powder extract on rats with renal hypertension and to evaluate the influence of it on the volume of urine and the concentrations of Na(+), K(+), Cl(-). METHODS: Reformed Gold-blatt hypertension rat model (G-2K1C) was established. The rats were divided into 6 groups as follows: sham-operation group; model group, Wuling Powder high dosage group (80 g/kg), Wuling Powder middle dosage group (40 g/kg), Wuling Powder low dosage group (20 g/kg), and hydrochlorothiazide (HCT) group (25 mg/kg). Urine volume of the rats was measured during the experiment. Tail arterial pressure and [Na(+)], [K(+)], [Cl(-)] in serum of the rats were detected after 30 days of treatment. RESULTS: The blood pressure of the G-2K1C rats was decreased in the three Wuling Powder groups (P<0.05 or P<0.01), but higher than that of the false-operation group (P<0.01), and there was no difference between each of the Wuling Powder groups and the HCT group (P>0.05). Diuretic effect of the three dosages of Wuling Powder was weaker than that of the HCT (P<0.05 or P<0.01). The effects of the three dosages of Wuling Powder and HCT on [Na(+)] and [Cl(-)] in the serum were not obviously different (P>0.05), but [K(+)] of the HCT group was significantly decreased compared with that of the false-operation group and the three Wuling Powder groups (P<0.01). CONCLUSION: Wuling Powder extract had satisfying therapeutic effects in increasing the discharge of urine, decreasing the blood pressure and keeping the balance of the serum electrolyte contents in rats with renal hypertension.