Nigella sativa L. Black cumin (Ranunculaceae) is one of the plants commonly used in Moroccan folk medicine for treatment of various ailments including diabetes mellitus.
Orally, black seed is also used for treating gastrointestinal conditions, colic, diarrhea, constipation and haemorrhoids. It is also used for respiratory conditions, asthma, allergies, cough, bronchitis, emphysema, flu and congestion.
Study undertaken to investigate the effect of different N. sativa seed extracts on insulin secretion
Different fractions of the seed were prepared: the defatted fraction (HR II), which was divided into two subfractions: the first (HR III) containing acidic and neutral compounds and the second (HR IV) containing basic compounds. The insulin secretory effects of these extracts were evaluated individually at different concentrations (0.01, 0.1, 1 and 5 mg/mL), in vitro in isolated rat pancreatic islets in the presence of 8.3 mmol/L glucose. The results show that addition of the defatted whole extract or of the basic subfraction of the seed in the incubation medium significantly increased glucose-induced insulin release from the islets. In the case of the acidic and neutral subfraction, the stimulatory effect was observed only for the higher concentration (5 mg/mL). However, a clear concentration-dependent increase in insulin release from isolated pancreatic islets was observed for the basic subfraction. Our data show that the antidiabetic properties of N. sativa seeds may be, at least partly, mediated by stimulated insulin release, and that the basic subfraction largely contributes to this stimulatory effect. Further phytochemical studies are underway in order to isolate the pharmacological compound(s) responsible for the insulinotropic effect of N. sativa seeds.
The hypoglycaemic effect of Nigella sativa oil is mediated by extrapancreatic actions
M. El-Darkhakhny, N. Mady, N. Lembert, H. P. T. Ammon,
The blood lowering effect of Nigella sativa oil was, however, not paralleled by a stimulation of insulin release in the presence of Nigella sativa oil, nigellone or thymoquinone. The data indicate that the hypoglycaemic effect of Nigella sativa may be mediated by extrapancreatic actions rather than by stimulated insulin release.
Hypoglycaemic effects of the volatile oil of Nigella sativa seeds
A. Al-Hadar, M. Aqel and Z. Hasan,
. . . The administration of the volatile oil was not found to alter basal insulin levels in all animal groups,which might suggest a non-insulin-mediated mechanism of action for the demonstrated hypoglycaemic activity. The mode of action of the hypoglycaemic effects exhibited by the volatile oil extracted from N. sativa seeds remains to be elucidated.
Antioxidant activity of Nigella sativa essential oil
M. Burtis and F. Bucar,
The results of the present study, which demonstrate the radical scavenging activity of Nigella sativa, indicate that the use of black cumin seeds for the treatment of various inflammatory diseases seems quite useful and reasonable.