Antimicrobial activity of Nigella sativa against resistant bacteria

Nigella sativa (Black cumin) seed, an important medicine of Tibbe nabwi (prophetic medicine) used for centuries for medicinal and culinary purposes is reported to possess a number of pharmacological properties. We tested its various extracts and oil in varying concentrations for antibacterial activity against standard strains and multiple antibiotics resistant clinical isolates of bacteria. Commercial sensitivity testing discs of commonly used antibiotics were used for sensitivity testing and comparison. Methanolic extract and oil showed pronounced dose dependant activity even upto 1:200 dilution. Among gram +ve bacteria tested, Bacillus subtilis, Staphylococcus aureus, S. epidermidis, other coagulase ¿ve staphylococci and S. pyogenes were sensitive to extract and oil. Among gram ¿ve bacteria tested, E. coli and Pseudomonas aeruginosa were sensitive to extract and P. aeruginosa to oil. Out of 158 strains tested, most of them were resistant to a number of antibiotics, 102 were inhibited by methanolic extract and 97 by oil. Our results are in conformity with earlier reports. The antibacterial activity N. sativa appears to be due to Thymol, Thymoquinone, Thymohydroquinone and tannins.