Comparative chemical profiling and antimicrobial activity of <i>Nigella sativa</i> seeds oils obtained from different sources

Abstract

<i>Nigella sativa</i> 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 <i>N. sativa</i> 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-<i>P. aeruginosa</i> action was attarin oil (MIC 12.5 µg/disc). Finally, the Sudanese market needs to standardise <i>N. sativa</i> seeds and oil.