Abstract

We investigated the chemical composition (by gas chromatography) and anti-microbial activity of the Tunisian Nigella sativa fixed oil against different standard Gram-negative and Gram-positive strains and Candida isolates by disc diffusion method, and determined the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and minimal fungicidal concentration (MFC) values. Twenty three fatty acids were identified in N. sativa fixed oil. Palmitic acid was the major saturated fatty acids (SFA) accounted for 12.2% of the total fatty acid (TFA). For monounsaturated fatty acids (MUFA), oleic acid was the major one with 21.67% of TFA. Linoleic acid has the most important percentage (58.73% of TFA) and was the major polyunsaturated fatty acids (PUFA). For the antibacterial activity, the best inhibition was seen against Staphylococcus aureus ATCC 25923 (16.66 mm) andSalmonella typhimurium ATCC 14028 (15.33 mm). The best antifugal activity was found against Candida parapsilosis ATCC 22019 (13.33 mm) and Candida glabata ATCC 90030 (12 mm). This fixed oil can be used as an antibacterial and antifungal agent each time the MIC values have a good effect on the antibacterial and antifungal activities of the TunisianN. sativa fixed oil. Our results demonstrate important antibacterial and antifungal activities of the Tunisian N. sativa fixed oil; these effects further validate the traditional use of N. sativain the folk medicine against bacterial and fungal infection.

Key words:  Nigella sativa, fixed oil, gas chromatography (GC), antibacterial activity and antifungal activity.