Influência da cafeína no perfil proteico e na viabilidade celular de Escherichia coli e potencial adjuvante para antibióticos

Abstract

Caffeine is a substance found in over 100 species of plants. In addition to its neurostimulant effects, its antimicrobial activity has already been proven by science, either alone or in combination with antibiotics. Combination therapies between natural compounds and antibiotics have been an effective strategy to fight bacterial resistance. In this context, the aim of this work was to test the influence of caffeine on the protein profile and cell viability of Escherichia coli and its adjuvant potential for antibiotics in vitro. At first, the concentration of caffeine to be used in the present study was determined, where it was shown that a concentration of 0.20 mg/mL allows for partial bacterial growth, without making the cells completely unviable. To perform the extraction of proteins from E. coli, two different methods were compared, one with acetone pa and the other with glass beads. By analyzing the SDS-PAGE and the densitometry of the extraction, it was concluded that the method with acetone was the most satisfactory. For the other tests, three generations of the bacteria were cultivated. Bacterial strains cultivated with caffeine showed alterations in the protein profile when compared to those cultivated in the absence of this substance, this fact was verified through SDS-PAGE and optical densitometry. After concluding that caffeine had an influence on the protein profile of the bacteria studied, its potential as an adjuvant to the antibiotics ampicillin and streptomycin was tested, the results of the adjuvant trial showed that caffeine was more effective when combined with ampicillin, reducing the inhibitory concentration minimum of this antibiotic from 0.250 mg/mL to 0.125 mg/mL. Taken together, the data found suggest that caffeine, alone or in combination with ampicillin, is a potential candidate for applications in antibacterial therapies.