Synthesis, Spectroscopic Studies, Antibacterial Activity, and Colorimetric Evaluation of the Time-Killing Assay for Newly Synthesized Chalcones Using Resazurin

Abstract

An attempt was made to synthesize and screen chalcones active against some Gram-positive and Gram-negative bacteria by adopting modified colorimetric technique for time-killing assay. A series of chalcones were synthesized from 1-(2-bromophenyl) ethanone and various substituted aromatic aldehydes with good yield and analyzed on the basis of spectral data (FT/IR, 1H NMR, and 13C NMR). The synthesized chalcones were screened for antibacterial activity against selected Gram-positive and Gram-negative bacteria. The pharmacokinetic profiles of chalcones were established by time-kill assay performed by colorimetry using resazurin dye as an indicator which colors only the viable cells. The ethoxy (compound I-4) and para-hydroxy (I-5) derivatives were found to be more potent against Gram-positive bacteria. The colorimetric time-kill assay was found to be more convenient and less time consuming than traditional cell viable count.