Abstract
The present study aimed to determine the effect of Hibiscus sabdariffa and Zingiber officinale on antihypertensive activity and pharmacokinetic of losartan in hypertensive rats. Hypertension was induced in rats by oral administration of L-NAME (40 mg/kg per day). Pharmacodynamics and pharmacokinetics of losartan were evaluated without and with herbal treatment in hypertensive rats. Treatment of hypertensive rats with investigated herbs substantially reduced systolic blood pressure (SBP), and diastolic blood pressure (DBP) of rats. Treatment of rats (n = 5) with L-NAME plus H. sabdariffa plus losartan and L-NAME plus Z. officinale plus losartan reduced SBP by 16.20% and 14.88% and DBP by 14.82% and 17.52% respectively after 12 h, as compared to L-NAME alone treated rats. In a pharmacokinetic study, the C-max and AUC(0-t) of losartan in L-NAME plus H. sabdariffa plus losartan and L-NAME plus Z. officinale plus losartan treated rats was increased by 0.7, 1.99 and 1.51, 3.00 fold respectively in comparison to the C-max and AUC(0-t) obtained for L-NAME plus losartan treated group. In conclusion, both the investigated herbs significantly increased the antihypertensive effect and plasma concentration of losartan in L-NAME induced hypertensive rats. The current study predicted that the herb-drug interaction between H. sabdariffa-losartan and Z. officinale-losartan could occur; hence these results in rats may warrant further studies in humans, either in humans or in in vitro human liver microsomes.