Comparative chemical profiling and antimicrobial activity of Nigella sativa seeds oils obtained from different sources

Abstract

Nigella sativa L. seeds are widely used in Sudan as a spice, food preservative, and medicine. Sudan does not grow the plant. The study aimed to compare the chemical profile and antibacterial activity of fixed and essential oils of N. sativa from Ethiopian and Indian seeds and the oil offered by Attarin in the local market. A Soxhlet device extracted fixed oils and hydrodistillation to obtain essential oils and analysed their oil profile using GC-MS. Disk diffusion was used to test antimicrobial activity. The fixed oil of Ethiopian (EFO) and Indian (IFO) seeds contained ten components, with linoleic acid (50.12% in EFO and 57.69% in IFO) being the most abundant. Ethiopian seeds were used to extract the essential oil. 51.96% of the oil was hydrogenated monoterpenes. The main chemicals were p-cymene (36.76%) and thymoquinone (18.70%). There were fixed and essential oils in the Attarin oil sample. The main component was linoleic acid (14.61%), followed by p-cymene (13.85%). The maximum antibacterial activity (MIC 6.25 µg/disc) was seen in both fixed and liquid oil samples against Escherichia coli and Pseudomonas aeruginosa. The best anti-P. aeruginosa action was attarin oil (MIC 12.5 µg/disc). Finally, the Sudanese market needs to standardise N. sativa seeds and oil.