2.3. Cytotoxicity of antibiotics and standards
Initially, cytotoxic concentration at 50% end point (CC50) for
the drugs were determined by 3-(4,5-dimethylthiazol-2-yl)-2, 5-
diphenyl tetrazolium bromide (MTT) assay [8,9]. Briefly, a 96
well plate (made by Genaxy) was pre-seeded with 3.5 × 105
cells/mL overnight. Next day, the MEM was discarded and
replaced with respective dose concentration of drugs starting
from 0 mg/mL to 520 mg/mL prepared in MEM. In control wells,
plain MEM was added and allowed to incubate for 72 h (37 C,
5% CO2). After incubation, MTT reagent was added under dark
conditions. Plate was again incubated for 4 h.