Mawoza T, Ojewole J A, Owira P M
Department of Pharmacology, School of Pharmacy and Pharmacology, Faculty of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.
Cardiovasc J Afr. 2012 Feb;23(1):12-7. doi: 10.5830/CVJA-2010-098.
Sclerocarya birrea (Anacardiaceae) is traditionally used for treating hypertension. The pharmacological effects of S birrea leaf aqueous extract (SBE) on rabbit and rat vascular smooth muscles were investigated in this study.
Fresh S birrea leaves (1 kg) were air dried at 26 ± 1°C, milled, macerated in 2.5 l of distilled water for 48 hours, filtered, and the filtrate was concentrated in a rotary evaporator. Rat isolated portal vein preparations, as well as rabbit isolated endothelium-denuded and endothelium-intact descending thoracic aortic ring preparations were mounted in 30-ml Ugo Basile organ baths under physiological conditions, and challenged with SBE (50-400 mg/ml). The contractile effects of SBE and/or other reference drugs on the isolated vascular smooth muscle preparations were recorded by means of Ugo Basile's force-displacement transducers and Gemini recorders.
SBE (50-400 mg/ml) caused a significant, concentration-dependent upward shift in baseline tone in the aortic ring preparations (p < 0.01-0.001). Indomethacin (20 µM) markedly attenuated the contractile effects of SBE in both the endothelium-intact and -denuded aortic rings, while N(G)-nitro-(L)-arginine methyl ester (L-NAME, 100 µM) significantly (p < 0.05) increased the contractile tension of the endothelium-intact aortic rings. Verapamil (1-3 µg/ml) partially inhibited the contractile effects of SBE. SBE also elicited significant (p < 0.05-0.01) increases in the amplitude of the myogenic contractions of the portal veins. These contractions were abolished by verapamil (1-3 µg/ml) in a concentration-dependent manner, while prazosin (1-3 µg/ml) did not affect the SBE-induced contractions.
SBE possessed spasmogenic effects on vascular smooth muscle preparations in vitro. It may induce and/or exacerbate hypertension, contrary to the folkloric, ethnomedical use of S birrea.
可乐豆木（漆树科）传统上用于治疗高血压。本研究调查了可乐豆木叶水提取物（SBE）对兔和大鼠血管平滑肌的药理作用。
将新鲜的可乐豆木叶（1千克）在26±1°C下风干、研磨，在2.5升蒸馏水中浸泡48小时，过滤，滤液在旋转蒸发仪中浓缩。将大鼠离体门静脉标本以及兔离体去内皮和完整内皮的胸降主动脉环标本置于生理条件下的30毫升乌戈·巴西莱器官浴槽中，并用SBE（50 - 400毫克/毫升）进行刺激。通过乌戈·巴西莱的力位移传感器和双子星记录仪记录SBE和/或其他参考药物对离体血管平滑肌标本的收缩作用。
SBE（50 - 400毫克/毫升）使主动脉环标本的基线张力显著、浓度依赖性地向上移位（p < 0.01 - 0.001）。吲哚美辛（20微摩尔）显著减弱了SBE在完整内皮和去内皮主动脉环中的收缩作用，而N(G)-硝基-(L)-精氨酸甲酯（L-NAME，100微摩尔）显著（p < 0.05）增加了完整内皮主动脉环的收缩张力。维拉帕米（1 - 3微克/毫升）部分抑制了SBE的收缩作用。SBE还使门静脉肌源性收缩的幅度显著（p < 0.05 - 0.01）增加。这些收缩被维拉帕米（1 - 3微克/毫升）以浓度依赖性方式消除，而哌唑嗪（1 - 3微克/毫升）不影响SBE诱导的收缩。
SBE在体外对血管平滑肌标本具有致痉挛作用。与可乐豆木的民间药用和民族医学用途相反，它可能诱发和/或加重高血压。
