The Hypoglycemic Effect of Nigella sativa Oil is Mediated by Extrapancreatic Actions

Abstract

A plant mixture containing extracts of Nigella sativa possesses blood glucose lowering effects, but the direct antidiabetic effect of Nigella sativa is not yet established. Therefore, the effect of Nigella sativa oil (NSO) on blood glucose concentrations was studied in streptozotocin diabetic rats. In addition, the effect of NSO, nigellone and thymoquinone were studied on insulin secretion of isolated rat pancreatic islets in the presence of 3, 5.6 or 11.1 mM glucose. NSO significantly lowered blood glucose concentrations in diabetic rats after 2, 4 and 6 weeks. The blood lowering effect of NSO was, however, not paralled by a stimulation of insulin release in the presence of NSO, nigellone or thymoquinone. The data indicate that the hypoglycemic effect of NSO may be mediated by extrapancreatic actions rather than by stimulated insulin release.

References

• 1 El-Dakhakhny M. Studies on the Egyptian Nigella sativa L. part IV. Some pharmacological properties of the seeds’ active principle in comparison to its dihydro-compound and its polymer.  Arzneimittel Forschung. 1965;  15 1227-9
• 2 Chakravarty N. Inhibition of histamine release from mast cells by nigellone.  Annals of Allergy. 1993;  70 237-42
• 3 Houghton P J, Zarka R, De las Heras B, Hoult R S. Fixed oil of Nigella sativa and derived thymoquinone inhibit eicosanoid generation in leukocytes and membrane lipid peroxidation.  Planta Medica. 1995;  61 33-6
• 4 Al-Awadi F, Famtania H, Shamte U. The effect of plants mixture extract on liver gluconeogenesis in STZ induced diabetic rats.  Diabetes Research. 1991;  18 163-8
• 5 El-Dakhakhny M. Studies on the chemical constitution of Egyptian Nigella sativa L Seeds II. The essential oil.  Planta Medica. 1963;  4 465-75
• 6 Lacy P E, Kostianovsky M. Methods for the isolation of intact islets of Langerhans from rat pancreas.  Diabetes. 1976;  16 35-9