Study of the antibacterial properties of new caffeine derivatives against opportunistic pathogenic bacteria in vitro

Introduction. The resistance of microbes to many classes of antimicrobial drugs is a global threat to human health and necessitates the search for new compounds with antimicrobial activity, with low toxicity and a potentially wide range of biological activity.

Aim. To study in vitro the ability of new xanthine derivatives (caffeine, 1-butyltheobromine and 7-butyltheophylline) to inhibit growth Staphylococcus (S.) aureus, Bacillus (B.) cereus, Escherichia (E.) coli and Pseudomonas (P.) aeruginosa.

Materials and methods. The antibacterial activity of xanthine derivatives synthesized in the Laboratory of Medicinal Chemistry of the N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry was studied in vitro using serial dilutions in a liquid nutrient medium against S. aureus, B. cereus, E. coli and P. aeruginosa cultures.

Results. Three substances, including the starting material – caffeine and 7-butyltheophylline, did not show antibacterial properties against test microbes. All xanthine derivatives studied did not inhibit the growth of E. coli and P. aeruginosa; 9 compounds containing fragments of amino acid esters or an acetylene substituent in the position of the C-8 xanthine backbone showed antibacterial activity against S. aureus and (or) B. cereus.

Conclusion. When studying the ability of natural xanthine caffeine and 12 of its derivatives to inhibit the growth of cultures of opportunistic bacteria, antibacterial properties against S. aureus and B. cereus were revealed in a number of amino acid derivatives. The best effect was shown by compounds containing fragments of alpha- and beta-amino acid esters (L-valine and beta-phenyl-beta-alanine), which determines the prospects for further research.

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