Effects of two-months Nigella sativa supplementation on cardiac hemodynamics and adrenergic responsiveness.

OBJECTIVE To study the effects of two, months Nigella sativa (N. sativa) oral supplementation to normal rats on cardiac haemodynamics in vivo, the ionotropic and chronotropic properties of the isolated hearts in vitro, and the cardiac responsiveness to progressive adrenergic stimulation by isoproterenol. METHODS The cardiac workload, after 2 months of N. sativa oral supplementation to normal adult rats, was assessed in vivo by measuring the cardiac pressure-rate product (mean arterial blood pressure multiplied by heart rate). Cardiac performance in vitro was evaluated by calculating the tension-rate product (developed peak tension multiplied by heart rate). The cardiac inotropic and chronotropic adrenergic responsiveness of N. sativa supplemented rats were evaluated in a Langendorff heart model upon graded infusion of the beta-adrenergic agonist isoproterenol. RESULTS The isolated hearts of Nigella-treated rats maintained their normal cardiac adrenergic responsiveness, with a selective enhancement of both the tension-rate product and the inotropic reserve. In contrast, the in vivo cardiac pressure-rate product in N. sativa supplemented rats was not significantly different from the control group. CONCLUSION The demonstrated favourable results of N. sativa supplementation on the intrinsic cardiac contractile properties without evidence of an increased cardiac work load or energy consumption in vivo makes N. sativa an attractive inotropic agent with an economic haemodynamic profile. Further research is recommended to explore the usefulness of N. sativa in cardiovascular disorders associated with systolic dysfunction.