The Effect of Polarity of Solvent on the Polyphenol Content and on their Antioxidant and Antibacterial Activity of Meals of the Grains of Nigella Sativa L

Mechraoui Omar and Segni Ladje

Abstract

Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. In this study we compared the phenolic contents, the antioxidant activity and antibacterial activity of the Nigella Sativa cakes using three solvent system of different polarity. Polyphenolic extractions of the dried powder samples were performed using three systems solvents 50%, 60%, 80% methanol. The phenolic content, analyzed using Folin-Ciocalteu, samples ranged from 0,9918 ± 0,0576 to 1,7918 ± 0,0785 mg/ g dry weight, expressed as gallic acid equivalents (GAE). The concentrations of total flavonoids, detected using 2% aluminum chloride ranged from 0,2220 ± 0,0269 to 0,4423 ± 0,0092 mg/g of catéchine equivalent (mgEC) dry weight. The Evaluation of antioxidant power and reducing power was performed using the method of DPPH free radical scavenging And the phosphomolybdat assay. The extract phenolic of the fruit having a moderate antimicrobial activity against reference strains of pathogens (Staphylococcus aureus and Pseudomonas aeruginosa) with a zone of inhibition in the range of 8.36 to 9.32 mm. In addition, most phenolic extracts inhibits the growth of pathogens used in this study.