Artemisia herba-alba Asso relaxes the rat aorta through activation of NO/cGMP pathway and K(ATP) channels.

Artemisia herba-alba Asso (Compositae) is used in oriental Morocco to treat diabetes and arterial hypertension. The present work evaluated the vasorelaxant effect of Artemisia herba-alba aqueous extract (AHAE) in isolated rat aorta and the mechanism underlying this effect. In endothelium-containing aorta preparations, AHAE (10(-3), 10(-2), 10(-1), 1 and 2 mg/mL) relaxed the contraction elicited by noradrenaline in a concentration-dependent manner. This effect is dependent upon integrity of the vascular endothelium as it was fully abolished in endothelium-denuded preparations. The vasorelaxant effect of AHAE (2 mg/mL) was also inhibited by N(G)-nitro-L-arginine methyl-ester (100 microM), methylene blue (10 microM) or 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (50 microM) but not by 10 microM atropine. This effect remained unchanged by tetraethylammonium (5 mM) or indomethacin (10 microM) whereas it was significantly attenuated by glibenclamide (10 microM). These results suggest that AHAE produces an endothelium-dependent relaxation of the isolated rat aorta, an effect that seems mainly mediated through stimulation of the endothelial nitric oxide synthase by mechanisms other than activation of muscarinic receptors. Activation of ATP-dependent potassium channels partly contributes in the mediation of AHAE-induced endothelium-dependent relaxation.

Effect of essential oil of Anthemis mauritiana Maire & Sennen flowers on intestinal smooth muscle contractility.

The aim of the present study is to determine the chemical composition of the essential oil extracted from the flowers of Anthemis mauritiana Maire & Sennen (EOAM) and to investigate its antispasmodic effects on intestinal smooth muscle. The phytochemical composition was revealed by gas chromatography-mass spectrometer. Eighteen compounds were identified representing 90.56% of the oil. The major constituents were described as alpha-pinene (27.02%), sabinene (15.25%), cedrenol (14.53%) germacrene (9.61%) geraniol formate (6.82%), and caryophylene (5.38%). EOAM (10-100 microg/ml) elicited reversible relaxation of spontaneous contractions of isolated rabbit jejunal smooth muscle preparations, and similarly inhibited contractions induced by high-potassium solution ([K(+)](o) = 76 mM) and carbachol (10(-6) M) with IC(50) values of 14.98 and 27.29 microg/ml, respectively. Furthermore, EOAM exhibited an inhibitory effect on the dose-response curves induced by carbachol and CaCl(2) on rat jejunum preparations. These results clearly demonstrated the antispasmodic effect of EOAM which was strongly suggested to be mainly due to an inhibitory effect on Ca(2+) influx through the membrane of jejunal smooth muscle cells.