Nigella sativa seed extracts enhance glucose‐induced insulin release from rat‐isolated Langerhans islets

Abstract

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. The present study was 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.

Antidiabetic Properties of a Spice Plant Nigella sativa

“…In parallel, significant slowdown of the body weight evolution was observed in NSO treated animals as compared to the control group [30]. In addition to NSO, the defatted extract of N. sativa also increases glucose induced insulin release in isolated rat pancreatic islets in concentration-dependent manner [39].…”

“…At the end of the 4-week treatment, N. sativa treated rats had lower fasting plasma levels of insulin and triglycerides while fasting plasma glucose remained stable throughout N. sativa treatment [38]. This suggests that N. sativa given for first 2 weeks increases serum insulin probably by stimulating glucose induced insulin secretion from beta-cells [39] and when the therapy continues for long the serum insulin decreases as serum glucose is not enough to induce more insulin secretion. Its anorexic effect may be useful in obesity.…”

In vitro and In vivo Anti-Microbial Effects of Nigella sativa Linn. Seed Extracts Against Clinical Isolates from Skin Wound Infections

“…After agar solidification, the well (7 mm in diameter) was cut from the agar to produce a total of three wells per each agar plate. For preliminary test, six concentrations of each extract (10,20,30,40, 50 and 60% v/v) were prepared in a total volume of 100 µL per well using 99.5% analytical Dimethyl Sulphoxide (DMSO) as an organic solvent. Chloramphenicol (10 µg/well) and amphotericin B (10 µg/well) were used as positive standard antibiotics.…”

“…The major component of oil is the fixed oil, while the volatile oil ranged between 0.4-0.7 percent [3] . Crude extracts and seed constituents of N. sativa, in particular thymoquinone, have been reported to possess a number of pharmacological properties [4] , like anti-oxidant [5] , anti-tumor [6,7] , anti-parasitic [8] , antiinflammatory [9] , anti-diabetic [10] , protection against nephrotoxicity [11] and hepatotoxicity [12] and acting as promoter of skin wound healing [13] . The anti-microbial effects of N. sativa seeds against different pathogenic microbes were investigated.…”

Use of Black Seed (Nigella Sativa L.) Oil in the Management of Hypertensive and Hyperlipidemic Individuals of District Muzaffarabad, Azad Kashmir, Pakistan

“…Its seeds and seeds extracts has been used medicinally for centuries especially in Mediterranean region, Middle-East and Southeast Asia (Rchid et al, 2004;Najmi, et al, 2008). It has tremendous traditional and pharmacological potential in curing a wide range of ailments particularly hypotension (Aqel, 1992) (Tasawar et al, 2011).…”