Caractérisation de l’huile des graines de Nigella sativa et étude de son activité hypoglycémiante et son hépato-toxicité

Abstract

In this study, we determined that the total oil of Nigella sativa is responsible for the hypoglycaemic effect of this plant. Its physical and chemical characteristics indicate that it has a high biological quality. Fractionation of this oil by column chromatography yielded two major fractions: the neutral oil, fractionated itself into four sub-fractions, and polar oil wich fractionation by chromatography yielded three polar sub-fractions. A analysis by GC and HPLC of the total oil and its neutral fractions allowed to reveal their composition in fatty acids, triglycerides and sterols and higher alcohols. These results indicate once again the richness of this oil on bioactive lipids compounds. These compounds would explain the pharmacological properties of Nigella sativa. The results also indicate that the polar fraction is responsible for the reduction of blood glucose in diabetic rats, according to a postprandial mechanism. The neutral fraction of the oil allows, for its part, the regeneration of islets of Langerhans after their destruction by streptozotocin. The toxicity of total Nigella sativa oil was also evaluated on thin slices of liver (PCLS). This approach has clearly shown that Nigella sativa oil had no hepato-protective effect against acetaminophen ( paracetamol ). The total oil and its two large polar and neutral fractions were evaluated for their toxicity in vivo. The results indicate that no significant traces of liver toxicity under the conditions used, quantity of extracts administered and duration of the test.