Evaluation of antioxidant activity and antimicrobial effect of Nigella sativa oil on some pathogenic bacteria and its interaction with chloramphenicol antibiotic

Nowadays, with the increase in diseases and consumers’ preference for organic foods, the use of natural plant compounds to improve and increase their shelf life is on the rise. In addition, the use of medicinal plants, which can have therapeutic properties, has attracted attention. Black seed oil has attracted a lot of attention in the past due to its unique therapeutic properties. The aim of this study was to investigate the antioxidant activity and evaluate the antimicrobial activity of black seed oil against Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The amount of phenolic compounds in black seed oil was measured by Folin-Ciocalteu. The antioxidant activity was determined by DPPH and ABTS radical scavenging methods. The antimicrobial effect of Nigella sativa oil was investigated according to well diffusion  agar, disk diffusion agar, interaction, minimum inhibitory concentration and minimum bactericidal concentration methods.The Nigella sativa oil had 16.25 mg GAE/g phenolic compounds. The antioxidant activity based on DPPH and ABTS radical scavenging were 86.62% and 94.85%, respectively.The Nigella sativa oil showed a significant antimicrobial effect on the tested microorganisms. In the combined mode (interaction) of Nigella sativa oil with chloramphenicol antibiotic, synergistic mode was observed for all bacterial strains. Given the significant antioxidant activity and antimicrobial effect of Nigella sativa, it can be used in food and pharmaceutical industries.