1. Educational Development Center, Mazandaran University of Medical Sciences, Sari, Iran 2. Departmet of physiology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
The use of artemisia annua as a drug is considerable due to containing extensive therapeutic effects, including anti diabetic and cardiovascular ones. a recent study showed that the aqueous extract of this plant reduces the contractile response of the aorta to phenylephrine (α1-adrenoceptor agonist); while its mechanisms were not assessed. therefore, at the present study we investigated the mechanisms underlying the vasodilatation effect of aqueous extract of artemisia annua in adult male rats.
The studied wistar rats were divided into 2 groups: vehicle-treated group (receiving saline by intra peritoneal, daily for a month), intact extract-treated (receiving an aqueous extract of artemisia annua 100mg/kg by intra peritoneal, daily for a month). at the end of the experimental duration, the isolated thoracic aorta was split into rings with and without endothelium. then contractile responses of aorta rings to phenylephrine concentrations (10-4 to 10-9 μmol) were recorded at present and/or absence of l-name as a no synthase inhibitor and indomethacin as a cyclooxygenase inhibitor. the recording of the contractile response was done by an isometric transducer f-60.
Comparison of contractile responses after and before adding l-name and indomethacin showed that contractile responses aorta rings with endothelium at present of these drugs significantly increased at all concentrations of phenylephrine (p<0.05–p<0.0001). furthermore, in endothelial aortic rings, the contractile response to some concentrations of phenylephrine was significantly increased in the presence of indomethacin (p<0.05).
It seems that one of the mechanisms involved in the vasorelaxation effect of this plant is indirect and dependent to endothelium by increasing the synthesis or release of no. in addition, artemisia annua can dilate the vessels directly and independent endothelium by releasing cyclooxygenase vasodilator products. so, with exploration of possible mechanisms of vasodilation effect of this medical plant, perhaps we can declare the mentioned plant is usable for cardiovascular disorders in metabolic defects.
Artemisia annua, vasodilatation, no synthase, cyclooxygenase.