Activités antioxydante et anticoagulante des polyphénols des graines de Nigella sativa L.

Abstract

The objective of this study is the evaluation of the antioxydant and anticoagulant activities of two polyphenolics extracts: extract without lipids (ED) and extract with lipids (EnD) obtained from the seeds of Nigella sativa.L in the area of Magra (M’sila). The qualitative analysis of the two extracts by TLC revealed the presence of many compounds, among which: quercetin and kæmpferol. The quantitative analysis of the two extracts by Folin-Ciocalteu assay revealed that these were rich in phenolic compounds and the content was 1544 et 1450 µg GAE/ml of extract, respectively. Also the content of flavonoïds was evaluated at 523 and 578,8 µg RE/ml of extract for the ED and the EnD, respectively. The antioxidant activity of the two extracts was evaluated in vitro by different tests (DPPH, β-carotene-linoleic acid and the reducing power). The two extracts demonstrates a great capacity to trap the DPPH˙ radical with IC50 of 7,08 and 6,50 μg /ml for the ED and the EnD, respectively. The results show that the two extracts are also able to inhibit lipid peroxydation with respectable percentages of about 73% for the ED and 84,67 % for the EnD and a great reducing power with EC50 of 3,35 and 5,13 µg /ml, respectively. The anticoagulant activity of these extracts was also evaluated in vitro by using the test of the cephalin-kaolin time, and the test of Quick time. The times of coagulation obtained on normal plasma in the presence of these extracts indicate that they carry an anticoagulant effect on the two pathway of coagulation with highly marked effect on the endogenous pathway than on the exogenous pathway and more important for the EnD than the ED.