Determination of MICs

MICs were determined using microdilution method as described by National Committee for Clinical Laboratory Standards (NCCLS) [34]. Briefly, the plant’s samples were prepared at concentrations of 50 mg/ml (stock solution) in sterile distilled water and serially diluted with distilled water to 20, 17.5, 15, 12.5, 10, 7.5, 5, 2.5, 1 and 0.5 μg/ml using nutrient broth followed by inoculation with 0.2 ml suspension of the test organisms. After 24 h of incubation at 37 °C, the test tubes were visually observed for growth. The lowest concentration at which no growth of the microorganism was observed was considered as MIC of the plant extract against the relevant strains of the microorganisms.