Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
J Ethnopharmacol. 2013 Jun 21;148(1):56-61. doi: 10.1016/j.jep.2013.03.061. Epub 2013 Apr 12.
Artemisia copa Phil. (Asteraceae) is a medicinal plant commonly used in traditional medicine in Argentina.
The vasorelaxant and hypotensive activities of the aqueous extract of Artemisia copa have been investigated.
The in vitro effect of the extract and isolated compounds from Artemisia copa was investigated using isolated rat aortic rings. The acute effect caused by the intravenous (i.v.) infusion (0.1-300mg/kg) on blood pressure and heart rate was evaluated in spontaneous hypertensive rats. In addition, a phytochemical analysis of the extract was performed by HPLC.
Artemisia copa had a relaxant effect in endothelium-intact aortic rings that had been pre-contracted with 10(-7)M phenylephrine (Emax=96.7±1.3%, EC50=1.1mg/ml), 10(-5)M 5-hydroxytriptamine (Emax=96.7±3.5%, EC50=1.5mg/ml) and 80mM KCl (Emax=97.9± 4.4%, EC50=1.6mg/ml). In denuded aortic rings contracted by phenylephrine, a similar pattern was observed (Emax=92.7±6.5%, EC50=1.8mg/ml). l-NAME, indomethacin, tetraethylammonium and glibenclamide were not able to block the relaxation induced by the extract. Nevertheless, the pre-treatment with Artemisia copa attenuated the CaCl2-induced contraction in a concentration-dependent manner (Emax: 86% of inhibition for 3mg/ml and 52% de-inhibition for 1mg/ml). This pre-treatment also induced a significant attenuation of the norepinephrine-induced contraction in a concentration-dependent manner (Emax: 72.7% of inhibition for 3mg/ml and 27% de inhibition for 1mg/ml) in a Ca(2+) free medium. Upon analyzing the composition of the extract, the presence of p-coumaric acid, isovitexin, luteolin and chrysoeriol were found. Luteolin (CE50: 1.5μg/ml), chrysoeriol (CE50: 13.2μg/ml) and p-coumaric acid (CE50: 95.2μg/ml), isolated from the aqueous extract, caused dilatation of thoracic aortic rings pre-contracted with phenylephrine. Artemisia copa administered i.v. also induced a decrease in the mean arterial pressure but did not affect the heart rate in hypertensive rats.
The aqueous extract of Artemisia copa proved to have vasorelaxing and hypotensive effects through the inhibition of Ca(2+) influx via membranous calcium channels and intracellular stores. The presence of luteolin, chrysoeriol and p-coumaric acid found in this plant could be involved in this effect.
Copa 属蒿草（菊科）是一种药用植物，在阿根廷传统医学中被广泛使用。
研究 Copa 属蒿草的水提物的血管舒张和降压活性。
使用分离的大鼠主动脉环研究提取物和 Copa 属蒿草分离化合物的体外作用。在自发性高血压大鼠中评估静脉（i.v.）输注（0.1-300mg/kg）引起的急性血压和心率变化。此外，通过 HPLC 对提取物进行了植物化学分析。
Copa 属蒿草对用 10(-7)M 苯肾上腺素（Emax=96.7±1.3%，EC50=1.1mg/ml）、10(-5)M 5-羟色胺（Emax=96.7±3.5%，EC50=1.5mg/ml）和 80mM KCl（Emax=97.9±4.4%，EC50=1.6mg/ml）预收缩的内皮完整主动脉环具有舒张作用。在用苯肾上腺素收缩的无内皮主动脉环中，观察到类似的模式（Emax=92.7±6.5%，EC50=1.8mg/ml）。l-NAME、吲哚美辛、四乙铵和格列本脲均不能阻断提取物诱导的舒张。然而，Copa 属蒿草预处理以浓度依赖性方式减弱了 CaCl2 诱导的收缩（Emax：3mg/ml 时抑制 86%，1mg/ml 时抑制 52%）。这种预处理还以浓度依赖性方式显著减弱了去钙介质中由去甲肾上腺素诱导的收缩（Emax：3mg/ml 时抑制 72.7%，1mg/ml 时抑制 27%）。在分析提取物的组成时，发现存在对香豆酸、异荭草苷、木樨草素和 chrysoeriol。从水提物中分离出的木樨草素（CE50：1.5μg/ml）、chrysoeriol（CE50：13.2μg/ml）和对香豆酸（CE50：95.2μg/ml）导致预收缩的胸主动脉环扩张用苯肾上腺素。静脉内给予 Copa 属蒿草也可降低平均动脉压，但不影响高血压大鼠的心率。
通过抑制膜钙通道和细胞内储存的 Ca2+内流，Copa 属蒿草的水提物显示出血管舒张和降压作用。在这种植物中发现的木樨草素、chrysoeriol 和对香豆酸可能参与了这种作用。
