Cardiovascular Activities Of Vernonia Amygdalina
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Date
2017-08
Authors
Tan, Ming Hooi
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
A few reviews on the ethno-medicinal use of Vernonia amygdalina for hypertension have been documented, but the scientific investigations are still very limited. The research was aimed to study the in vitro and in vivo cardiovascular effects of V. amygdalina leaf extracts. The dried leaf samples were successively extracted with petroleum ether (VAPE), chloroform (VACE), methanol (VAME) and water (VAWE). These extracts were examined for vasorelaxant activity in isolated rat thoracic aortic rings, hypotensive activity in anesthetized rats, anti-hypertensive activity, arterial stiffness and biochemical changes in spontaneous hypertensive rats (SHRs). The most effective vasorelaxant and hypotensive plant extracts were subjected for further fractionation and the possible mechanisms were elucidated. Lastly, phytochemical analysis of the most bioactive extract and fraction of V. amygdalina using gas chromatography mass spectrometry and high performance liquid chromatography were performed. The results showed that all V. amygdalina extracts evoke a vasodilating and hypotensive activity although the effective concentrations for each extract are different; VACE exhibit the most potent vasorelaxant activity whereas VAPE exhibit the most potent hypotensive activity. The acute and chronic (28 days) oral administration of 500 mg/kg V. amygdalina extracts induced a marked and sustained antihypertensive effects. Hexane-insoluble fraction of VACE (HI-VACE) exhibited an endothelium independent effect and calcium antagonistic activity. On the contrary, 10 μM L-NAME, 10 μM methylene blue, 10 μM indomethacin, 1 μM atropine, 1 μM propranolol, 1 μM prazosin did not alter HI-VACE-induced relaxation, indicating that eNOS-NO-sGC-cGMP pathways, prostanoids production, muscarinic receptor and adrenergic receptor are not involved.
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Keywords
Cardiovascular activities of , Vernonia amygdalina