Composition and biological activities of the essential oil of Nigella sativa seeds isolated by accelerated microwave steam distillation with cryogenic grinding

In this study, essential oil of Sahara Nigella sativa L. was extracted using a rapid extraction, the
microwave steam distillation (MSD) and the cryogenic grinding (CG). Two procedures have been
investigated, the MSD1 (seeds inside of oven apparatus) and MSD2 (seeds outside of oven
apparatus). Forty-six compounds were identified and significant differences in quantities of the major
constituents were observed, mainly were thymoquinone (CLG: 331.82-443.55 mg and CG: 272.95-
413.57 mg/100 g of seeds), p-cymene (CLG: 181.71-244.17 mg, CG: 369.80- 374.40 mg/100 g of
seeds), dehydro-sabina ketone (CLG: 24.60- 25.83 mg, GC: 44.02-50.69 mg/100g of seeds),
carvacrol (CLG: 10.32-10.96 mg, CG: 3.91-12.67 mg/100 g of seeds) and longifolene (CLG: 11.90-
16.43 mg, CG: 12.72-19.58 mg/100 g of seeds).Results showed that essential oils exhibit a good
activity in each antioxidant system with a special attention for β-carotene bleaching test (IC50: 21 to
27 μg/ml) and reducing power (EC50: 9 to 14 μg/ml).The N. Sativa essential oils exhibited higher
antibacterial and antifungal activities varying according to technique extraction and grinding mode
used, with a high effectiveness against Gram-positive bacteria with a diameter of inhibition zones
growth ranging from 9.5 to 35 mm and MIC and MBC values ranging from (0.042–0.10 mg/ml) to (0.20–0.75 mg/ml), respectively