Structure-Activity Relationship (SAR) Studies of Chalcone-Based Molecules with Antimicrobial Activity

Abstract

Chalcones are flexible families of alpha, beta unsaturated ketones of fairly wide biological praise, in addition to remarkable antimicrobial activities. In this paper, the structure activity relationships (SAR) of a combination of chalcone-derivatives were synthesized and evaluated critically in terms of the effects the certain structural changes have on the antimicrobial activities. A set of twelve chalcone analogues was prepared by Claisen-Schmidt condensation and their structure was determined by FTIR, 1H- NMR, and mass spectrometry. Their antimicrobial activity was tested on Escherichia coli, Staphylococcus aureus and Candida albicans by broth microdilution technique so as to obtain minimum inhibitory concentrations (MICs) of various antibiotics. Analysis of SAR indicated that the presence of electron-withdrawing groups at para of aromatic ring, especially halogen, and nitro group increased the antimicrobial activity notably. On the other hand, the electron-donating groups lowered activity. Inclusion of hydroxyl groups enhanced the antifungal wires as well. Considering such findings, the following results can be of great value in terms of structural optimization and further development of chalcone-based antimicrobial agents.