Departamento de Farmacología, Facultad de Medicina, Universidad de Panamá, Panama.
J Ethnopharmacol. 2010 Sep 15;131(2):497-501. doi: 10.1016/j.jep.2010.06.036. Epub 2010 Jun 30.
Cecropia obtusifolia (Cecropiaceae) and Psychotria poeppigiana (Synonym: Cephaelis elata, Rubiaceae) are two Latin American plants broadly used in traditional Amerindian medicine. The former, together with many other species of the genus Cecropia, share the folk reputation of curing heart failure, cough, asthma and bronchitis. The latter is used in Panama by Kuna and Ngäbe Buglé (Guaymies) native Indians for the treatment of dyspnea.
Based on screening of selected medicinal Panamanian plants by radioligand-binding techniques by Caballero-George et al. (2001), the present study was carried out in order to investigate the vasoactive effects of different fractions from both P. poeppigiana and C. obtusifolia on rat thoracic aorta and identify active fractions and their chemical constituents.
Both acid and neutral methanol fractions (P-AMeOH and P-NMeOH) and acid and neutral dichlorometane fractions (P-ADCM and P-NDCM) were obtained from P. poeppigiana crude methanolic and dichlorometane extracts, respectively. Identical fractionation was carried out for C. obtusifolia (C-AMeOH, C-NMeOH, C-ADCM and C-NDCM. Vasorelaxant effect of all fractions, and their inhibition of contractile responses to angiotensin II were evaluated in isolated aortic rings.
P-AMeOH, P-NMeOH and P-ADCM fractions induced a concentration-dependent relaxation (43.9+/-1.8%, 35.3+/-4.7% and 52.9+/-3.5%, respectively) in the endothelium-intact aorta precontracted by phenylephrine (PE, 10(-6)M). The relaxation produced by C-AMeOH and C-NMeOH (57.3+/-2.5% and 53.3+/-3.3%, respectively) was greater than the effect produced by C-ADCM and C-NDCM (42.2+/-3.4% and 21.8+/-0.8%, respectively). Only the incubation of the aortic rings with P-AMeOH reduced the maximum contraction induced by angiotensin II at 20.08+/-0.55%.
The direct vasorelaxation effect observed could explain in part the ethnomedical use of these plants in Amerindian traditional medicine. The most active fractions contain phenolic and aromatic acid compounds. Furthermore, P-AMeOH, the only fraction that showed both vasorelaxant effect and inhibition of contractile responses to angiotensin II, is the most rich in aromatic acids compounds and the only one that contains scopoletin.
Cecropia obtusifolia（山龙眼科）和 Psychotria poeppigiana（同义词： Cephaelis elata，茜草科）是两种在拉丁美洲传统印第安医学中广泛使用的植物。前者与山龙眼属的许多其他物种一起，享有治疗心力衰竭、咳嗽、哮喘和支气管炎的民间声誉。后者在巴拿马被库纳和恩加贝·布格勒（瓜米埃斯）的印第安人用于治疗呼吸困难。
基于 Caballero-George 等人（2001 年）使用放射性配体结合技术对选定的巴拿马药用植物进行的筛选，本研究旨在调查 P. poeppigiana 和 C. obtusifolia 的不同部分对大鼠胸主动脉的血管活性作用，并鉴定活性部分及其化学组成。
从 P. poeppigiana 粗甲醇和二氯甲烷提取物中分别获得酸和中性甲醇部分（P-AMeOH 和 P-NMeOH）以及酸和中性二氯甲烷部分（P-ADCM 和 P-NDCM）。对 C. obtusifolia 进行相同的分级分离（C-AMeOH、C-NMeOH、C-ADCM 和 C-NDCM）。评估所有部分的血管舒张作用及其对血管紧张素 II 引起的收缩反应的抑制作用。
P-AMeOH、P-NMeOH 和 P-ADCM 部分在预先用苯肾上腺素（PE，10（-6）M）收缩的内皮完整主动脉中诱导浓度依赖性舒张（分别为 43.9+/-1.8%、35.3+/-4.7%和 52.9+/-3.5%）。C-AMeOH 和 C-NMeOH 产生的舒张作用（分别为 57.3+/-2.5%和 53.3+/-3.3%）大于 C-ADCM 和 C-NDCM（分别为 42.2+/-3.4%和 21.8+/-0.8%）。只有用 P-AMeOH 孵育主动脉环，才能降低血管紧张素 II 引起的最大收缩至 20.08+/-0.55%。
观察到的直接血管舒张作用部分可以解释这些植物在印第安传统医学中的民间用途。最活跃的部分含有酚类和芳香酸化合物。此外，P-AMeOH 是唯一同时具有血管舒张作用和抑制血管紧张素 II 收缩反应的部分，它富含芳香酸化合物，也是唯一含有山莨菪亭的部分。
