SCREENING OF ANTIMICROBIAL PROPERTIES OF PHENOL SCHIFF BASES

In their fight for supremacy and survival, microorganisms have been developing and devising various methods to inactivate the action of antibiotics. The numbers of drug resistant microorganisms with reduced susceptibility to various antibiotics are increasing. Therefore, new infection-fighting strategies are required to control microbial infections. The interaction between potent chemicals and living system contribute to the understanding of life processes and provide effective methods for treatment, prevention and diagnosis of many diseases. Phenol Schiff bases like chalcone imines and flavone imines were screened for their antimicrobial activity against a wide range of pathogenic bacteria and fungi. The in vitro activity of the compounds was evaluated by the Kirby-Bauer disc diffusion method and the MIC was determined for a few selected compounds. Most of the compounds showed significant antimicrobial activity. The compounds were found toxic to bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, S. typhimurium, Shigella flexneri and Proteus species. Pseudomonas aeruginosa was found to be resistant to most of the compounds. It was noted that all the compounds were active against fungi like Cryptococcus neoformans, Candida albicans, Trichophyton mentagrophytes, Microsporum gypseum, Mucor and Rhizopus but inactive towards Aspergillus niger, Asp. flavus and Asp. fumigatus. It was interesting to note that the compounds were more fungi toxic than antibacterial. Flavone imines showed more antimicrobial activity than chalcone imines.