Vascular effects of Tanacetum vulgare L. leaf extract: In vitro pharmacological study

Aim of the studyTanacetum vulgare L. (Asteraceae/Compositae) is principally used in traditional Moroccan medicine as antihypertensive remedy. The aim of the present study was to investigate the in vitro vascular activity of the aqueous extract of Tanacetum vulgare L.Materials and MethodsThe activity of Tanacetum vulgare L. extract was tested on contractile response of Wistar rat aorta to high KCl and noradrenaline and on endothelium-dependent relaxation evoked by acetylcholine.ResultsThe addition of Tanacetum extract during the plateau phase of noradrenaline-evoked contraction produced a rapid relaxation that reached a maximum of 30% of the contraction and was suppressed by the NO synthase inhibitor NG-nitro-l-arginine. At higher extract concentrations this rapid relaxation was followed by a slowly developing, NG-nitro-l-arginine-resistant, relaxing effect. Tanacetum extract also depressed KCl-evoked contraction by 30% at maximum. This effect was abolished in the presence of NG-nitro-l-arginine. The endothelium-dependent relaxation induced by acetylcholine was depressed in the presence of Tanacetum extract in the bathing solution.Conclusion:This study indicates that the aqueous extract of Tanacetum possesses NO-mediated and NO-independent vasorelaxing properties in vitro.