The Antibacterial Property of Nigella sativa (Black seed) Oil Against Gram-positive and Gram-negative Bacteria

Abstract

Antibacetrial resistance and bacterial genetic modification is one of the most challenges that face the world today, and it is heading toward the post-antibiotic era. Traditionally, herbal extracts, medicinal plant oil extracts, and probiotics have been used as an alternative to antibiotics, because most bacteria become resistant agenst antibiotic inspit of drug side effects. This work is designed to estimate the antibacterial efficacy of Nigella sativa (N.sativa) oil extracts against common antibiotic resistant bacteria, including Methicillin-resistant staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa). The black seed was purchased from the traditional herbal medicine market. The oil was extracted using Hydro distillation and steam distillation method. The bacteria were obtained from a microbiology company and from clinical samples at the Shar hospital in Sulaimani Provence. The Gram-negative bacteria were; Salmonella enterica (S. enterica), Escherichia coli (E.coli), and Pseudomonas aeruginosa (P. aerouginosa) while the Gram-positive bacteria were; MRSA, Bacillus subtilis (B.subtilis), and Bacillus cereus (B.cereus). The agar diffusion well technique and minimum inhibitory concentration (MIC) were followed for determining the antibacterial effect of N. sative oil. The black seed oil components were analyzed by the Gas Chromatograph mass spectrum. The results revealed that the oil has direct effect on Gram-positive bacterial growth, including MRSA, which is known as a multidrug resistance bacterium. Bacillus subtilis was more sensitive than other strains, and the significant antibacterial effect of the extracted was observed against E. coil, while it has no significant effect on P. aeruginosa and Salmonella enterica. Determination of Nigella sativa oil minimum inhibitory concentration (MIC) for Gram-positive bacteria is 100 ml for Staphylococcus aureus and Bacillus subtilis, and the MIC was 200 ml and 400 ml for Bacillus cereus and MRSA respectively. This study concludes that oil extract of Nigella sativa is a good natural antimicrobial, it can be used against MRSA and other Gram-positive bacteria.