Spergularia marina: a potential source of a novel calcium channel blocker with antihypertensive and diuretic activities

C.A. Ismail, A.M. Baraka, R.M. Abdallah, O.G. El-Dien, D.K. Mostafa

Department of Clinical Pharmacology, Faculty of Medicine, Alexandria University, Alexandria, Egypt. dalia.kashishy@alexmed.edu.eg

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• Plant biology

OBJECTIVE: Spergularia marina (L.) Griseb. (S. marina) is a sub-cosmopolitan species used as traditional phytotherapy based on diverse biological activities. It is native and widespread in the northern hemisphere, though introduced also into the southern hemisphere. The extract of another species ‘Spergularia purpurea’ has been traditionally used in Morocco against various diseases and S. marina, itself, is a local popular food in South Korea. In this context, we evaluated the potential antihypertensive and diuretic effects of S. marina water and n-butanol extracts in L-NAME-induced hypertensive rats vs. the well-known diuretic, furosemide.

MATERIALS AND METHODS: After toxicity studies, selected doses were administered orally daily for one week. Mean arterial blood pressure (MABP), water/electrolyte clearance, renal functions, and serum electrolytes were assessed. Vascular reactivity of isolated aortic rings was evaluated under different incubating settings against various antagonists to unravel the mechanism of action.

RESULTS: Both extracts significantly reduced the MABP. Only, the n-butanol fraction exerted a significant aquaresis, increasing electrolyte free-water clearance with a significantly decreased urinary Na+, K+, and C– excretion. The water extract significantly augmented the ACh-induced relaxation and attenuated the NE-induced aortic rings’ contractile response. It also exhibited a direct relaxant effect on the NE-precontracted rings with intact or denuded endothelium. Blocking the vascular calcium channels by preincubation with nifedipine prevented the S. marina-induced relaxation, denoting a calcium channel blocking activity.

CONCLUSIONS: The vasorelaxant and the differential diuretic effects of both extracts introduce S. marina as a potential novel antihypertensive agent with calcium channel blocking activity. To enrich cardiovascular therapeutics, human studies to confirm the efficacy and safety of S. marina in hypertension are warranted.

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