Vascular mechanisms underlying the hypotensive effect of Rumex acetosa

Abstract

Context:Rumex acetosa L. (Polygonaceae) is well known in traditional medicine for its therapeutic efficacy as an antihypertensive.Objective: The study investigates antihypertensive potential of crude methanol extract (Ra.Cr) and fractions of Rumex acetosa in normotensive and hypertensive rat models and probes the underlying vascular mechanisms.Materials and methods: Ra.Cr and its fractions were tested in vivo on normotensive and hypertensive Sprague-Dawley rats under anaesthesia for blood pressure lowering effect. In vitro experiments on rat and Oryctolagus cuniculus rabbit aortae were employed to probe the underlying vasorelaxant mechanism.Results: In normotensive rats under anaesthesia, Ra.Cr caused fall in MAP (40 mmHg) at 50 mg/kg with % fall of 27.88 ± 4.55. Among the fractions tested, aqueous fraction was more potent at the dose of 50 mg/kg with % fall of 45.63 ± 2.84. In hypertensive rats under similar conditions, extract and fractions showed antihypertensive effect at same doses while aqueous fraction being more potent, exhibited 68.53 ± 4.45% fall in MAP (70 mmHg). In isolated rat aortic rings precontracted with phenylephrine (PE), Ra.Cr and fractions induced endothelium-dependent vasorelaxation, which was partially blocked in presence of l-NAME, indomethacin and atropine. In isolated rabbit aortic rings pre-contracted with PE and K+-(80 mM), Ra.Cr induced vasorelaxation and shifted Ca2+ concentration–response curves to the right and suppressed PE peak formation, similar to verapamil, in Ca2+-free medium.Discussion and conclusions: The data indicate that l-NAME and atropine-sensitive endothelial-derived NO and COX enzyme inhibitors and Ca2+ entry blocking-mediated vasodilator effect of the extract explain its antihypertensive potential.

Isolation and biological activities of compounds from Rumex vesicarius L. and their use as a component of a synbiotic preparation

“…Further, ERA exhibits endothelium-independent modulation of calcium entry through voltage-gated Ca +2 channels and release from internal calcium stores. These actions likely underlie its antihypertensive influence in normotensive and salt-induced hypertensive rats ( Qamar et al, 2018 ). Ahmad et al (2016) reported that an essential oil isolated from R. hastatus inhibits cholinesterase activity.…”

Pharmacological evaluation of Euphorbia hirta, Fagonia indica and Capparis decidua in hypertension through in-vivo and in vitro-assays

“…Whereas it was established that calcium influx via VDCCs and ROCs amplified the calcium contents of cytosol in response to high K + and P.E addition to organ bath [52,53], which resultantly trigger a persistent contractions. It has also been demonstrated that calcium channel blockers possesses antioxidant properties which reduce endothelial dysfunction by restoring NO availability [54,55].…”

“…Whereas it was established that calcium influx via VDCCs and ROCs amplified the calcium contents of cytosol in response to high K + and P.E addition to organ bath [ 52 , 53 ], which resultantly trigger a persistent contractions. It has also been demonstrated that calcium channel blockers possesses antioxidant properties which reduce endothelial dysfunction by restoring NO availability [ 54 , 55 ]. It has also been demonstrated that nifedipine, a standard CCBs, preserves endothelial integrity in patients with hypertension [ 56 ] and hence E. hirta , F. indica and C. decidua showed additional antihypertensive mechanism in arsenic-induced hypertensive rats via improving the endothelium damage by additional CCBs type constituents.…”

Evaluation of Proximate Composition, Minerals and Micronutrient Contents of Finger Millet Herbi Dumpling

“…"This herb is used in food products with medicinal properties related to its tannin content [15]. Previous studies reported that Rumex acetosa possessed antioxidant, anti-hypertensive, antiviral, and anticancer effects" [16,17,18].…”