Pharmacological basis for the medicinal use of Wrightia tinctoria in hypertension and dyslipidemia.

This study was aimed to offer a possible pharmacological basis regarding the remedial utilization of Wrightia tinctoria in hypertension and dyslipidemia in certain South Asian traditional systems of medicine, using in vivo and in vitro assays. The aqueous methanolic extract of W. tinctoria seeds (Wt.Cr) caused a dose-dependent (1-10 mg/kg) decrease in arterial pressure in anesthetized rats. In the right atria of isolated guinea pigs, Wt.Cr equally inhibited force and rate of spontaneous atrial contractions. When tested on phenylephrine-, high K(+)-, and low K(+)-induced vasoconstrictions in isolated rat aorta, Wt.Cr produced a concentration-dependent vasorelaxation, the most potent being against low K(+)-induced contraction. It also created a rightward shift in the Ca(++) concentration-response curves and suppressed phenylephrine control peaks in a Ca(++)-free environment. In the rat model of tyloxapol-induced dyslipidemia, Wt.Cr produced a decline in the serum levels of total cholesterol and triglycerides. In high fat diet-induced dyslipidemia, it decreased serum total cholesterol and low-density lipoprotein cholesterol, improved high-density lipoprotein cholesterol, and prevented the increase in average body weights by causing a decrease in diet consumption. These data suggest that Wt.Cr(++) lowers blood pressure through a combination of K(+)-channel opening and Ca(++)-channel blocking effects along with antidyslipidemic and weight-reducing properties.