Relaxant effects of the neutral extract of the leaves of Bidens pilosa Linn on isolated rat vascular smooth muscle
Relaxant effects of the neutral extract of the leaves of Bidens pilosa Linn on isolated rat vascular smooth muscle
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DOI：
10.1002/ptr.1646
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发表时间：
2005-03-01
影响因子：
7.2
通讯作者：
Kamanyi, A
中科院分区：
文献类型：
--
作者：
Nguelefack, TB;Dimo, T;Kamanyi, A
鬼针草中性提取物的持久降压作用被认为是由于血管扩张所致。目前的工作就是为了评估这一假说。用氯化钾或去甲肾上腺素收缩大鼠离体主动脉，观察其中性提取物(NBP)的血管舒缩作用。NBP在0.25~1.5 mg/mL的浓度范围内，对KCl60 mM预收缩的大鼠主动脉具有浓度依赖性的血管松弛作用，收缩幅度为25%~105%。1.5 mg/mL的最大浓度可使去甲肾上腺素引起的收缩反应松弛88%。丹参提取物对有、无内皮血管条的作用无明显差异。在吲哚美辛或马来酸吡咯胺存在下，植物提取物诱导的松弛反应在较低浓度时被显著抑制。该植物提取物能降低大鼠主动脉静息张力，抑制KCl1.5 mg/mL90%的收缩作用和0.75 mg/mLCaCl2引起的95%的收缩作用。这些结果证明了鬼针草中性提取物的血管扩张特性，并表明它可能是一种钙拮抗剂。版权所有(C)2005 John Wiley&Sons，Ltd.
The long-lasting antihypertensive effect of a neutral extract of Bidens pilosa has been suggested to be due to vasodilation. The present work was undertaken to assess this hypothesis. The vasorelaxant effect of a neutral extract (NBp) of the leaves of B. pilosa was evaluated in vitro on isolated rat aorta contracted with KCl or norepinephrine. NBp induced a concentration-dependent vasorelaxation of the rat aorta precontracted with KCl (60 mm) by 25%-105% at the respective concentrations of 0.25-1.5 mg/mL. The maximal concentration of 1.5 mg/mL provoked 88% relaxation of norepinephrine-induced contractions. There were no significant differences between the effects of the extract on the aorta strips with or without endothelium. In the presence of indomethacin or pyrilamine maleate, the relaxant response induced by the plant extract was significantly inhibited at the lower concentrations. The plant extract was able to reduce the aorta resting tone, inhibit the KCl-induced contractions (90% at 1.5 mg/mL) and the CaCl2-induced contractions by 95% at a concentration of 0.75 mg/mL. These results demonstrate the vasodilating properties of the neutral extract of Bidens pilosa and indicate that it may act as a calcium antagonist. Copyright (c) 2005 John Wiley & Sons, Ltd.