Express assessment of thiosemicarbazones of 2,4-disubstituted 1-aryl-imidazole-5-carbaldehydes and some of their derivatives antimicrobial activity

Abstract

Aim – to investigate antimicrobial activity of thiosemicarbazones of 2,4-disubstituted 1-aryl-imidazole-5-carbaldehydes and certain their derivatives in vitro as a precondition for further targeted synthesis of new compounds with predicted antimicrobial properties. Material and Methods. Up to 25 new chemical compounds of chemical synthesis underwent an express evaluation of antimicrobial activity – thiosemicarbazones of 2,4-disubstituted 1-aryl-imidazole-5-carbaldehydes and some of their derivatives. Study of antibacterial and antifungal action of the compounds on reference strains of Gram-positive and Gram-negative bacteria and yeasts was conducted using common methods of twofold serial dilutions in liquid culture medium and determination of the minimal fungistatic and bacteriostatic or bactericidal and minimal fungicidal concentrations. Results. Conducted microbiological study has revealed that the tested compounds showed moderate antimicrobial activity – minimal bacteriostatic concentration of the vast majority of them regarding the reference strains of Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 was in the range of 31.25–62.5 mg/ml, and the minimal bactericidal concentration was two - four times higher and were 62.5–500 mg/ml. In the study of thiosemicarbazones of 2,4-disubstituted 1-aryl-imidazole-5-carbaldehydes and some of their derivatives anticandida activity it has been found that it exceeded their antibacterial activity. Minimal fungistatic concentration for the vast majority (84 %) of the investigated compounds on Candida albicans ATCC 885–653 was in the range of 15.62 to 31.25 mg/ml, and the minimal fungicidal concentrations, respectively, from 15.62 to 250 mg/ml. It has been established that the introduction of the azide group cycle in the position 2 of imidazole cycle reduced bactericidal activity twice and the introduction of thiazolide fragment – by 4 times. Conclusions. Thiosemicarbazones of 2,4-disubstituted 1-aryl-imidazole-5-carbaldehydes and some of their derivatives show antimicrobial activity against both Gram-positive and Gram-negative bacteria and yeast-like fungi. It has been established that the antimicrobial activity of the studied compounds depended on their chemical structure. The results are a prerequisite for further targeted synthesis of new compounds with predicted antimicrobial properties.

Keywords

• carbaldehydes
• antimicrobial properties
• antibacterial compounds
• antifungal action