Short and long term modulation of tissue minerals concentrations following oral administration of black cumin (Nigella sativa L.) seed oil to laboratory rats

Background: Nigella sativa, or commonly called black cumin is a small herb of family Ranunculaceae is a well-known medicinal plant but its effects on tissue mineral concentrations of animal bodies is unknown.

Purpose: To study the effect of oral administration of fixed oil of black cumin seeds on tissues mineral content using laboratory rats as experimental model.

Study design: Experimental animals were exposed to two oral doses of seed oil (60 and 120 ml kg^-1 body weight). Short- and long term experiments lasted 24 h and 60 days respectively, with three replicates each.

Methods: Oil extracted from black cumin seeds was subjected to GC-MS to identify chemical components. Following the wet digestion in nitric acid, samples of whole blood and organs of rats were subjected to atomic absorption spectrophotometry for determination of elements concentrations. Data were compared statistically at p < .05.

Results: Compared to control, Cr, Mn, Ni, Cu, Zn showed decrease, whereas Co, Na, Mg and K demonstrated increase, but Ca showed both increase and decrease in most of the tissues upon short term exposure to low and high doses of black cumin oil. During long term exposure, Cr, Fe, Mn, Cu exhibited decrease; Co, Na, Mg and Ca concentrations demonstrated an upregulation, whereas Ni and Zn showed increase and decrease in most of the tissues. Comparison of short term with long term experiments at low dose revealed increases in Fe, Zn, Cu, Mg, K and Ca, a decrease in Cr, Mn, Ni and Cu in most tissues, but both increase and decrease in Na. At high dose, an increase occurred in Fe, Ni, Zn, K, Ca, Mg, a decrease in Cr, while both increase and decrease in Cu, Co and Na concentrations.

Conclusion: Our study demonstrates that oral administration of black cumin seeds oil to laboratory rats significantly alters tissue trace elements and electrolytes concentrations. The study appears beneficial but indicates modulatory role of black cumin oil as regards mineral metabolism with far reaching implications in health and disease.