Adegunloye B J, Omoniyi J O, Owolabi O A, Ajagbonna O P, Sofola O A, Coker H A
Department of Physiology and Pharmaceutical Chemistry, College of Medicine, University of Lagos, Nigeria.
Afr J Med Med Sci. 1996 Sep;25(3):235-8.
The antihypertensive effect of aqueous extracts of the calyx of Hibiscus sabdariffa (HS) has been investigated in anaesthetized rats. Hibiscus sabdariffa caused a dose-dependent decrease in mean arterial pressure (MAP) of the rats. Sectioning of the right and left vagi nerves did not have a significant effect on the fall in MAP produced by HS. Cholinergic blockade with 0.2 mgkg-1 atropine and histaminergic blockade with 1 mgkg-1 cimetidine and 15 mgkg-1 promethazine significantly attenuated the hypotensive response to HS. Pretreatment of the rats with 20 mgkg-1 HS extract did not have a significant effect on increase in blood pressure induced by bilateral carotid occlusion (48.05 +/- 6.83 mmHg vs 46.53 +/- 7.49 mmHg). The cumulative addition of HS to noradrenaline precontracted aortic rings produced dose-dependent relaxation of the rings. The maximum relaxation response was 86.96 +/- 5.20% and this was observed at the dose of 1.70 mgml-1. These findings suggest that the antihypertensive effect of the extracts of calyx of HS is not mediated through inhibition of the sympathetic nervous system but it could be mediated through acetylcholine-like and histamine-like mechanisms as well as via direct vaso-relaxant effects.
在麻醉大鼠中研究了玫瑰茄花萼水提取物的降压作用。玫瑰茄导致大鼠平均动脉压（MAP）呈剂量依赖性下降。切断左右迷走神经对玫瑰茄引起的MAP下降没有显著影响。用0.2mg/kg阿托品进行胆碱能阻滞以及用1mg/kg西咪替丁和15mg/kg异丙嗪进行组胺能阻滞可显著减弱对玫瑰茄的降压反应。用20mg/kg玫瑰茄提取物预处理大鼠对双侧颈动脉闭塞引起的血压升高没有显著影响（48.05±6.83mmHg对46.53±7.49mmHg）。向去甲肾上腺素预收缩的主动脉环中累积添加玫瑰茄可使环产生剂量依赖性舒张。最大舒张反应为86.96±5.20%，在1.70mg/ml的剂量下观察到该反应。这些发现表明，玫瑰茄花萼提取物的降压作用不是通过抑制交感神经系统介导的，而是可能通过乙酰胆碱样和组胺样机制以及直接的血管舒张作用介导的。
