Pharmacological evidence of hypotensive activity of Marrubium vulgare and Foeniculum vulgare in spontaneously hypertensive rat

The hypotensive effects of the water extract of Marrubium vulgare L. and Fo eniculum vulgare L. were investigated in spontaneously hypertensive rats (S HR) and in normotensive Wistar-Kyoto rats (WKY). Oral administration of Mar rubium or Foeniculum extract lowered the systolic blood pressure of SHR but not of WKY. In SHR, Foeniculum but not Marrubium treatment increased water , sodium and potassium excretion. Ex vivo as well as in vitro. Marrubium ex tract inhibited the contractile responses of rat aorta to noradrenaline and to KCl (100 mM). Inhibition was greater in aorta from SHR compared to WKY and was not affected by the NO synthase inhibitor N-nitro-L-arginine. Vascu lar effects of Foeniculum extract were less pronounced than those of Marrub ium and were blocked by N-nitro-L-arginine. These results indicate that hyp otensive activity of Marrubium and Foeniculum extracts seems to be mediated through different pathways: Foeniculum appeared to act mainly as a diureti c and a natriuretic while Marrubium displayed vascular relaxant activity.