Nguelefack-Mbuyo P E, Nguelefack T B, Dongmo A B, Afkir S, Azebaze A G B, Dimo T, Legssyer A, Kamanyi A, Ziyyat A
Department of Animal Biology and Physiology, Laboratory of Animal Physiology, University of Yaounde I, BP 812 Yaounde, Cameroon.
J Ethnopharmacol. 2008 May 22;117(3):446-50. doi: 10.1016/j.jep.2008.02.028. Epub 2008 Mar 4.
The methanol/methylene chloride (CH(3)OH/CH(2)Cl(2)) extract from the stem bark of Mammea africana was showed to possess vasodilating effect in the presence and the absence of N(omega)-nitro-l-arginine methyl ester (l-NAME). The present study was designed to evaluate the effects of the methanol/methylene chloride from the stem bark of Mammea africana.
The extract (200 mg/(kg day)) was administered orally in rats treated concurrently with l-NAME (40 mg/(kg day)). l-Arginine (100 mg/(kg day)) and captopril (20 mg/(kg day))were used as positive controls. Bodyweight, systolic arterial blood pressure and heart rate were measured weekly throughout the experiment period (28 days). At the end of treatment, animals were killed and the cardiac mass index evaluated. The aorta was used to evaluate the endothelium-dependant relaxation to carbachol. The aorta contraction induced by noradrenalin was also examined and expressed as a percentage of that induced by KCl.
The extract neither affected the body weight nor the heart rate. The extract as captopril completely prevented the development of arterial hypertension. Both the substances failed to restore the endothelium-dependent vascular relaxation and increased the vascular contraction to norepinephrine in relation to KCl contraction. They also significantly reduced the left ventricular hypertrophy induced by l-NAME.
These findings are in agreement with the traditional use of Mammea africana in the treatment of arterial hypertension and indicate that it may have a beneficial effect in patients with NO deficiency but will be unable to improve their endothelium-dependent vasorelaxation.
非洲牛油果茎皮的甲醇/二氯甲烷（CH₃OH/CH₂Cl₂）提取物在存在和不存在N（ω）-硝基-L-精氨酸甲酯（L-NAME）的情况下均显示出血管舒张作用。本研究旨在评估非洲牛油果茎皮甲醇/二氯甲烷提取物的作用。
提取物（200毫克/（千克·天））经口给予同时接受L-NAME（40毫克/（千克·天））治疗的大鼠。L-精氨酸（100毫克/（千克·天））和卡托普利（20毫克/（千克·天））用作阳性对照。在整个实验期（28天）每周测量体重、收缩期动脉血压和心率。治疗结束时，处死动物并评估心脏质量指数。用主动脉评估对卡巴胆碱的内皮依赖性舒张。还检测了去甲肾上腺素诱导的主动脉收缩，并表示为氯化钾诱导收缩的百分比。
提取物既不影响体重也不影响心率。提取物与卡托普利一样完全预防了动脉高血压的发展。两种物质均未能恢复内皮依赖性血管舒张，且相对于氯化钾收缩，增加了血管对去甲肾上腺素的收缩。它们还显著减轻了L-NAME诱导的左心室肥厚。
这些发现与非洲牛油果在治疗动脉高血压方面的传统用途一致，并表明它可能对一氧化氮缺乏的患者有有益作用，但无法改善其内皮依赖性血管舒张。
