Fredi Cifuentes1, Adrián Paredes2, Javier Palacios3, Fernanda Muñoz1, Lorena Carvajal1, Chukwuemeka R Nwokocha4, Glauco Morales2. 1. Experimental Physiology Laboratory (EPhyL), and. 2. Laboratorio de Química Biológica, Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile. 3. Departamento de Ciencias Químicas y Farmacéuticas, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile. Electronic address: clpalaci@unap.cl. 4. Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Mona, Kingston 7, Jamaica, W.I.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Senecio nutans Sch. Bip. (Compositae) is an endemic plant of South America used in the management of acute mountain sickness in the Andean communities. Currently, the direct effects of hydroalcoholic extract from S. nutans on the cardiovascular system are unknown. The aim of this study was to determine the effects and mechanism of action of S. nutans on cardiovascular function in normotensive and Angiotensin II (1μg/mL) hypertension mice models. MATERIAL AND METHODS: Blood pressure and ECG measurements were simultaneously carried out on the mice and rats. The isolated right atrium, papillary muscle of the left ventricle and isolated heart of rat were used to study the cardiac functions and mechanisms. RESULTS: S. nutans (40mg/Kg) induced a 30% and 12% significant (p<0.05) reduction of the mean arterial pressure (MAP) in normotensive and hypertensive mice respectively. This decrease was as a result of decrease in heart rate (HR) in normotensive (25%) and hypertensive model (31%). It also decreased the sinus rhythm in isolated right atrium of rat. Compared with Losartan, a known anti-hypertensive, S. nutans caused a dose-dependent negative inotropic effect (dP/dtmax) on Langendorff isolated heart system. While Losartan, decreased the MAP by 30% but had no effect on heart rate. The calcium blocker nifedipine had similar effects as S. nutans, decreasing the beat frequency of isolated right atrium and contractility of papillary muscle of the left ventricle of rat. CONCLUSION: The results suggest an important clinical function in hypertension therapy, as S. nutans could decrease the blood pressure in hypertensive mice by decreasing the HR and contractility, leading to a reduction in myocardial oxygen demand.
ETHNOPHARMACOLOGICAL RELEVANCE: Senecio nutans Sch. Bip. (Compositae) is an endemic plant of South America used in the management of acute mountain sickness in the Andean communities. Currently, the direct effects of hydroalcoholic extract from S. nutans on the cardiovascular system are unknown. The aim of this study was to determine the effects and mechanism of action of S. nutans on cardiovascular function in normotensive and Angiotensin II (1μg/mL) hypertensionmice models. MATERIAL AND METHODS: Blood pressure and ECG measurements were simultaneously carried out on the mice and rats. The isolated right atrium, papillary muscle of the left ventricle and isolated heart of rat were used to study the cardiac functions and mechanisms. RESULTS:S. nutans (40mg/Kg) induced a 30% and 12% significant (p<0.05) reduction of the mean arterial pressure (MAP) in normotensive and hypertensivemice respectively. This decrease was as a result of decrease in heart rate (HR) in normotensive (25%) and hypertensive model (31%). It also decreased the sinus rhythm in isolated right atrium of rat. Compared with Losartan, a known anti-hypertensive, S. nutans caused a dose-dependent negative inotropic effect (dP/dtmax) on Langendorff isolated heart system. While Losartan, decreased the MAP by 30% but had no effect on heart rate. The calcium blocker nifedipine had similar effects as S. nutans, decreasing the beat frequency of isolated right atrium and contractility of papillary muscle of the left ventricle of rat. CONCLUSION: The results suggest an important clinical function in hypertension therapy, as S. nutans could decrease the blood pressure in hypertensivemice by decreasing the HR and contractility, leading to a reduction in myocardial oxygen demand.
Authors: Javier Palacios; José Miguel Fonseca; Fernando Ayavire; Felipe Salas; Mirko Ortiz; Juan Marcelo Sandoval; Julio Benites; Chukwuemeka R Nwokocha; Ewaldo Zavala; Adrián Paredes; Iván Barría; José Luis Vega; Fredi Cifuentes Journal: Oxid Med Cell Longev Date: 2018-07-26 Impact factor: 6.543