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[摘要]：The aim of this work was to evaluate the antihypertensive activity of the hydroalcohol extract of the leaves of Syzygium guineense (Willd) D. C. (Myrtaceae) in a 1-kidney-1-clip rat model and its vasorelaxant effect on isolated aorta. The extract reduced blood pressure in a dose and time dependent fashion. Following 3 days of treatment, single oral daily doses of 50, 100 and 150 mg/kg caused an overall reduction (p < 0.05) of systolic blood pressure by 6.9, 34.0 and 40.8 mmHg, respectively. The diastolic blood pressure was, however, significantly reduced (p < 0.05) by 100 mg/kg (10.3 mmHg) and 150 mg/kg (18.4 mmHg) doses only. The mean blood pressure was reduced by 5.0, 18.3 and 25.9 mmHg by the respective doses. The extract also caused a dose-dependent relaxation of aorta precontracted with KCl at a concentration of 5-70 mg/mL, with a maximum relaxation of 56.22% achieved at 70 mg/mL concentration. The relaxation mechanism was found to be independent of the endothelium system, muscarinic receptors, histamine receptors, ATP dependent K+ channels, cyclooxygenase enzymes and cGMP/NO pathway. The findings suggest that the extract had an antihypertensive effect most likely caused by dilation of the blood vessels, a confirmation for the folkloric use of the plant. Copyright (c) 2010 John Wiley & Sons, Ltd. |
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