Attenuation of L-NAME-induced Hypertension in Rats with Elettaria cardamomum–Low-dose Amlodipine Combination: A Possible Synergism of Covasodilatory Effect

Abstract

Background Hypertension is a prevalent chronic disorder that affects approximately 1.28 billion adults worldwide. In the use of amlodipine, though it is a cost-effective antihypertensive agent, it causes side effect that may lead to discontinuation of the medication. Purpose To examine the effect of the combination of Elettaria cardamomum plus a low dose of amlodipine on Nω-nitro-l-arginine methyl ester (L-NAME)-induced hypertensive rat model. Materials and Methods Thirty adult male Wistar rats were randomized into five groups of six rats, respectively. The standard control group received only normal saline (first group). The other four groups received L-NAME (40 mg/kg/day, orally) for 21 days as follows: Group 2 served as L-NAME group only; Group 3 was given E. cardamomum (400 mg/kg/day, orally); Group 4 received amlodipine (5 mg/kg/day, orally); Group 5 received E. cardamomum (400 mg/kg/day, orally) + a low dose of amlodipine (2.5 mg/kg/day, orally) and served as the combination treatment group. Twenty-four hours after the last treatment, blood pressure was measured, then blood samples were collected, rats were sacrificed, and hearts and kidneys were harvested. Serum levels of lipids, liver enzymes, urea, and creatinine were determined. Results L-NAME administration induced a notable increase in systolic, diastolic, and mean arterial blood pressure, with significant changes in biochemical parameters. However, administration of E. cardamomum alone or in combination with a low dose of amlodipine showed a better reduction in systolic and diastolic blood pressure than amlodipine alone. Consequently, effects on liver enzymes, lipid profile, and cardiorenal pathology were significantly improved with combination treatment compared with amlodipine alone. Conclusion The present study has shown that the E. cardamomum–low-dose amlodipine combination could be beneficial in lowering blood pressure without the attendant adverse effects associated with the normal dose of amlodipine alone. This could be due to covasorelaxant effects.