Antibacterial activity of Nigella sativa seed extracts

Abstract

The development and alarming increase of bacterial resistance to existing antimicrobial agents has become a real challenge and a serious problem facing patients suffering from various infections worldwide. This study was designed to evaluate the antibacterial activity of black seed extracts against bacterial isolates (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa). The powdered seeds were extracted using percolation technique with methanol and petroleum ether. Agar well diffusion method was used to test the antibacterial activity. Methanolic extracts at 100mg/ml had a remarkable activity against S. aureus (19mm) and P. aeruginosa (12mm). Also the petroleum ether extract had the same activity against S. aureus and P. aeruginosa (10mm). This implies that methanolic and petroleum ether extracts of N. sativa were found to be active against S. aureus and P. aeruginosa. While E. coli showed resistance to the extracts at all concentrations. Our study shows that species, strains and concentrations of N. sativa extracts are some of the factors that may influence the sensitivity of tested organisms.

Keywords: Antibacterial activity, Nigella sativa, Black seed extract, Agar well diffusion, Bacterial isolates