Antibacterial effect of Nigella sativa (Kalojira) against Staphylococcus aureus and Escherichia coli.

Bacterial infection is one of the biggest causes of morbidity and mortality worldwide. Pathogens have also gradually developed resistance to the miracle drug, antibiotics. That's why interest in searching for effective alternatives for the current antibiotics with different mode of action on microbes is increasing. In this regard, one of the reputed medicinal plants, Nigella sativa (Kalojira) was investigated for potential antibacterial effect against commonly encountered pathogens (Staphylococcus aureus and Escherichia coli). Both aqueous and ethanolic extract of Kalojira was found active against Staphylococcus aureus and Escherichia coli in disc diffusion method. Zone of inhibitions of aqueous extract at 100.0% (1000μg/ml) concentrations were 25mm against Staphylococcus aureus, 24mm against Escherichia coli. Zone of inhibitions of ethanolic extract were 32mm against Staphylococcus aureus and 32mm against Escherichia coli at 100.0% concentration. The broth dilution technique was performed to determine the MICs of Aqueous kalojira extract (AKE), EKE and Amikacin. The MICs of AKE were 500μg/ml and 600μg/ml against Staphylococcus aureus and Escherichia coli respectively. The MICs of EKE were 400μg/ml and 400μg/ml against aforesaid organism respectively. The MIC of Amikacin was 1.5μg/ml against Staphylococcus aureus and 1μg/ml against Escherichia coli. The MIC of Amikacin was lowest in comparison to MICs of AKE and EKE for the test organisms. The subculture study showed the same results with that of previous experiments.