Nigella sativa seed extracts enhance glucose-induced insulin release from rat-isolated Langerhans islets.
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.
Laboratoire de Recherche sur les Substances Naturelles Végétales, Université Montpellier II UPRES EA 1677, Place E. Bataillon, Bât. 15, CC 024, 34095 Montpellier Cedex 05, France. rchidhalima@hotmail.com
Halima
H
Rchid
Hugues
H
Chevassus
Rachid
R
Nmila
Carine
C
Guiral
Pierre
P
Petit
Mustapha
M
Chokaïri
Yves
Y
Sauvaire
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology*; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D031881:Nigella sativa / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds / Q000737:chemistry
D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D005947:Glucose