Evaluation of Cardiovascular Effects of Edible Fruits of Syzygium cumini Myrtaceae (L) Skeels in Rats

• Published in: Tropical journal of pharmaceutical research Vol. 13; no. 11; p. 1853
• Main Authors: de A. Herculano, Edla, da Costa, Cintia D.F, Rodrigues, Amanda K.B.F, Araújo-Júnior, João X, Santana, Antônio E.G, França, Paulo H.B, de A. Gomes, Ednaldo, Salvador, Marcos J, de B.P. Moura, Flávia, Ribeiro, Êurica A.N
• Format: Journal Article
• Language: English
• Published: Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria 01-11-2014
• Subjects: Antihypertensive; Edible fruits; Hypotension; Syzygium cumini; Vasorelaxation
• ISSN: 1596-5996; 1596-9827
• DOI: 10.4314/tjpr.v13i11.12

Purpose: To evaluate the hypotensive, vasorelaxant and antihypertensive
effects elicited by the hydroalcohol extract from the fruits of
Syzygium cumini (EHSCF) in non-anesthetized rats. Methods: The rats
were anesthetized and polyethylene catheters were inserted into the
lower abdominal aorta and into the inferior vena cava for blood
pressure measurements and administration of drugs. After a recovery
period of 24 h, EHSCF (0.5; 1; 5; 10; 20 and 30 mg/kg, i.v.) was
administered in non-anesthetized rats. The mean arterial pressure and
the heart rate were recorded. To investigate the effects of extract,
doses EHSCF were administered after pretreatment with L-NAME, atropine,
indomethacin, and hexamethonium. For measurement of isometric tension,
a concentration-response curve was obtained after Phenylephrine and KCl
(80 mM) pre-contractions. The bioactive extract was analyzed via mass
spectrometry (MS) fingerprinting using direct electrospray ionization
mass spectrometry (ESI-MS). Results: EHSCF (0.5; 1; 5; 10; 20 and 30
mg/kg) induced hypotension (-15 ± 1, -14 ± 1, -15 ± 1,
-13 ± 1, -11 ± 1 and -13 ± 2 %) and bradycardia (-6
± 1, -5 ± 1, -6 ± 1, -14 ± 1, -8 ± 1 and -10
± 2 %) in normotensive rats. These responses were attenuated by
pre-treatment with L-NAME, indomethacin, hexamethonium or atropine. In
phenylephrine, pre-contracted mesenteric rings, EHSCF-induced
relaxation (Emax = 54.6 ± 4.5 % and pD2 = 2.7 ± 0.1) that
were affected by endothelium removal. EHSCF caused relaxant effect of
KCl (80 mM) pre-contracted rings (Emax = 100 ± 0.2 % and pD2 = 2.2
± 0.1). This effect was not changed in denuded rings. A single
oral administration of the extract reduced significant mean arterial
pressure in spontaneously hypertensive rats. ESI-MS/MS analyses of
EHSCF demonstrated that the major constituents of the analyzed samples
coincided with the mass of the malic, gallic, caffeic and ferulic
acids. Conclusion: The results suggest that EHSCF induces hypotension
probably due to a decrease in peripheral resistance, mediated by the
endothelium. Bradycardia may be due to indirect cardiac muscarinic
activation. The extract also causes an antihypertensive effect.