Studies on the antihypertensive and antidyslipidemic activities of Viola odorata leaves extract

Abstract

BackgroundThis study was undertaken to provide pharmacological basis for the medicinal use of Viola odorata Linn. in hypertension and dyslipidemia using the in vivo and in vitro assays.ResultsViola odorata leaves extract (Vo.Cr), which tested positive for alkaloids, saponins, tannins, phenolics, coumarins and flavonoids, caused a dose-dependent (0.1-1.0 mg/kg) decrease in mean arterial blood pressure in anaesthetized rats. In isolated guinea-pig atria, Vo.Cr equally inhibited force and rate of spontaneous atrial contractions. On the baseline of rat thoracic aortae (endothelium-intact and denuded), the plant extract caused phentolamine-sensitive vasoconstriction. When tested on phenylephrine (PE, 1 μM) and K+ (80 mM)-induced vasoconstriction, Vo.Cr caused a concentration-dependent relaxation and also caused a rightward shift of Ca++ concentration-response curves as well as suppression of PE (1 μM) control peaks in Ca++-free medium, similar to that caused by verapamil. In the presence of L-NAME, the relaxation curve of Vo.Cr was partially inhibited showing involvement of Nitric oxide (NO) mediated pathway. In Tyloxapol-induced dyslipidemia, Vo.Cr caused reduction in total cholesterol and triglyceride levels. In high-fat diet-induced dyslipidemia model, the plant extract caused a significant decrease in total cholesterol, LDL-C, atherogenic index and prevented the increase in average body weights, while it increased HDL-C.ConclusionsThese data indicate that the vasodilator effect of the plant extract is mediated through multiple pathways like inhibition of Ca++ influx via membranous Ca++ channels, its release from intracellular stores and NO-mediated pathways, which possibly explain the fall in BP. The plant also showed reduction in body weight and antidyslipidemic effect which may be due to the inhibition of synthesis and absorption of lipids and antioxidant activities. Thus, this study provides a pharmacologic rationale to the medicinal use of Viola odorata in hypertension and dyslipidemia.

Comparative effects of different fractions of crude aqueous extract of Ficus exasperata leaves on blood pressure

“…This extract reduced blood pressure by activation of muscarinic receptors (Ghayur and Giliani, 2006). Similar effects had also been reported for leaf extract Viola odorata which tested positive for alkaloids, saponins, tannins, flavonoids and phenols (Siddiqi et al, 2012).…”

Viola odorata

“…Viola odorata leaf extract caused a reduction in total cholesterol and triglyceride levels in tyloxapol-induced dyslipidemia (Siddiqi et al 2012 ). In high-fat diet-induced dyslipidemia model, the plant extract caused a signifi cant decrease in total cholesterol, LDL-C and atherogenic index and prevented the increase in average body weights, while it increased HDL-C.…”

Perfil lipídico sérico de ratos tratados com surfactante

“…O surfactante tyloxapol, um detergente não iônico, através da sua habilidade em inibir a lipase lipoprotéica (LLP) 7,8 , induz ao aumento do colesterol e triacilgliceróis séricos, além de favorecer o aumento da atividade da enzima hidroximetilglutaril -CoAredutase (HMG-CoA), que é a enzima-chave intracelular para síntese do colesterol hepático 4,5,9,10,11 . …”