Letter to the Editor Cardiac inotropic and hypertrophic effects of Nigella sativa supplementation in rats ☆ M.N. El-Bahai ⁎ , M.T. Al-Hariri, T. Yar, A.O. Bamosa Department of Physiology, College of Medicine, King Faisal University, PO Box 2114, Dammam, 31451, Saudi Arabia Received 9 June 2007; accepted 1 July 2007 Available online 1 November 2007 Abstract The intrinsic cardiac responses to 2-months Nigella sativa (black seed) oral supplementation (800 mg/kg) in rats were investigated. The isolated hearts were perfused in a Langendorff preparation to demonstrate the effects of N. sativa on the baseline inotropic and chronotropic functions and the myocardial flow rate. N. sativa supplementation induced moderate global (homogenous) cardiac hypertrophy, evident by significant increases in left ventricular and whole heart weights as well as the relative heart weight/body weight ratio. The isolated perfused hearts of Nigella-treated rats showed enhanced levels of baseline peak tension, maximum rate of tension development, heart rate and myocardial flow rate. Moreover, there was a significant increase in the tension developed per gram left ventricular weight. The present study provides the first evidence of a physiological cardiac hypertrophy in rats induced by long term N. sativa supplementation. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Nigella sativa; Cardiac contractility; Inotropy; Cardiac hypertrophy; Isolated hearts; Intrinsic cardiac properties The use of plants as medicines dates from the earliest years of human life. Nigella sativa (N. sativa) is one of these safe plants used as an herb for more than 2000 years and has been shown to produce multi-systemic beneficial actions [1], including hypoglycemic [2], hypocholestermic [3], and antioxidant [4] effects. There is some controversy about the cardiovascular actions of N. sativa or its active ingredients as some investigators reported no effect on blood pressure levels in animals [5] or humans [6] whereas others reported a dose-dependent decrease in the arterial blood pressure and heart rate in normal [7] or spontaneously hypertensive rats [8] respectively. The literature does not show any previous study evaluating the effect of N. sativa supplementation on the intrinsic properties of the cardiac muscle. Therefore, this study was carried out to investigate the effect of long term oral administration of N. sativa on cardiac weight and the baseline inotropic and chronotropic functions of the isolated hearts of N. sativa treated rats, perfused in Langendorff preparation. 1. Methods Fifty normal adult Wister albino male rats (150–250 g) were divided equally into experimental and control groups. Nigella-treated rats received a daily oral dose of 800 mg/ kg of N. sativa which corresponds to the submaximal dose of thymoquinone previously shown to produce hypotensive effect in rats [7]. A crude suspension of grounded seeds in distilled water (100 mg N. sativa/ml) was prepared before each feeding and the daily dose of N. sativa was given through orogastric feeding. An equivalent volume of water was administered by the same route to the control rats. Each rat was weighed and injected intraperitoneally with 5000 IU (1 ml) heparin sodium. Rats were anaesthetized with intraperitoneal phenobarbital (40 mg/kg body weight of the animal). The heart of each animal was removed through a International Journal of Cardiology 131 (2009) e115 – e117 www.elsevier.com/locate/ijcard ☆ This work was supported by a grant from King Faisal University, Dammam, Saudi Arabia. ⁎ Corresponding author. Tel.: +966 3 8577000x2058. E-mail address: nabil_elbahai@hotmail.com (M.N. El-Bahai). 0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2007.07.075