~ 65 ~ The Pharma Innovation Journal 2022; 11(6): 65-71 ISSN (E): 2277-7695 ISSN (P): 2349-8242 NAAS Rating: 5.23 TPI 2022; 11(6): 65-71 © 2022 TPI www.thepharmajournal.com Received: 17-02-2022 Accepted: 28-05-2022 Oussou N’guessan Jean-Baptiste Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire N’dia Kouadio Frédéric Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire Kouakou Kouakou Léandre Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire Bohue Hollywalley Alex Innocent Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire Ehile Ehouan Etienne Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire Corresponding Author: Oussou N’guessan Jean-Baptiste Laboratory of Physiology, Pharmacology and Pharmacopoeia, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire Hypotensive and cardio-inhibitor effects of Cajanus cajan harms (fabaceae) aqueous leaf extract in anesthetized normotensive rabbits Oussou N’guessan Jean-Baptiste, N’dia Kouadio Frédéric, Kouakou Kouakou Léandre, Bohue Hollywalley Alex Innocent and Ehile Ehouan Etienne Abstract Cajanus cajan (Fabaceae) is a plant traditionally used in Cote d’Ivoire to treat many illnesses such as sickle-cell anemia, measles and diabetes. To our knowledge, no research works were undertaken on its probable effect against cardiovascular diseases. Therefore, the present study aims to assess the hypotensive and cardio-inhibitor effects of C. cajan leaves extract (AqECc) through the arterial blood pressure (BP) and the electrocardiogram (ECG) recording in anesthetized rabbits. The carotid artery was intubated using a catheter connected to Ludwig's mercury manometer for BP measurement. The recording of the ECG was performed using an electrocardiograph. Varied C. cajan macerate doses (0.5 to 50 mg/kg bw) were administered to anesthetized rabbits intravenously. Phytochemical analysis was carried out in order to determine the phytoconstituents contained in the extract. Results showed that AqECc induced a dose dependent hypotension in normotensive rabbits with a fifty percent effective dose (ED50) of 9.33 mg/kg b.w. The hypotension induced by AqECc was significantly reduced by atropine (a muscarinic cholinoreceptor antagonist). On rabbits’ electrocardiogram, AqECc decreased the amplitudes of P-wave, QRS complex, T-wave and the heart rate. As for the duration of PQ interval, it was significantly (p< 0.05) increased. However, the extract had no significant effect on the QT interval. Phytochemical screening results of the extract revealed the presence of sterols and polyterpenes, phenols, flavonoids, catechic tannins, alkaloids and saponins which are known for their hypotensive effects could explain the use of this plant by traditional healers to treat hypertension. Keywords: Cajanus cajan, hypotension, cardio-inhibition, rabbit, phytoconstituents 1. Introduction Blood pressure (BP) is created by the force exerted by the blood on the walls of blood vessels as it is pumped by the heart [1] . Classified as a non-communicable disease, high blood pressure is a devastating medical condition in which the blood vessels have persistently raised pressure [2] . Arterial hypertension is the most widespread cardiovascular disease in black Africa population [3] . It is characterized by increase in systolic and/or diastolic pressures higher than 160 mmHg and 95 mmHg respectively, it constitutes a public health problem with very serious consequences including about 5% of cases of cerebrovascular disease worldwide [4] . Approximately one-quarter of the global adult population is hypertensive and this proportion is expected to reach 29.2% (about 1.6 billion people) by 2025. Out of total 58.8 million deaths worldwide in year 2004, high blood pressure was responsible for 12.8% (7.5 million deaths) [5] . In sub-Saharan Africa, this condition currently affects approximately 27-28% of the adult population of age 20 and above. The World Health Organization (WHO) in 2005 estimated the overall prevalence of arterial hypertension in Côte d’Ivoire to be 21.7% and this was significantly more important in rural areas with 29.6% against 21% in urban areas [6] . The prevalence of hypertension has increased, especially in low-income countries. Despite the increasing prevalence, the proportions of hypertension awareness, treatment and BP control are low, particularly in low-income countries, and few comprehensive assessments of the economic impact of hypertension exist [7] . Various anti-hypertensive drugs have been used in the treatment of hypertension. Though most of these medicines have been found helpful, they nevertheless come with several problems such as side effects and high cost, which limit their extensive use [8] . Hence studies are warranted on implementation of novel strategies for hypertension prevention, treatment and control.