Atividade antibacteriana e antibiofilme de óleorresinas extraídas de duas espécies de copaíba contra Staphylococcus aureus e avaliação da toxicidade

Abstract

Healthcare-associated infections (HAIs) affect patients under medical care during or after hospital admission, and are associated with numerous deaths annually, directly impacting global public health. This problem is exacerbated by the presence of strains exhibiting antimicrobial resistance, potentially leading to the ineffectiveness of antibiotic therapies. In this context, Staphylococcus aureus is a pathogen of great importance due to its frequent association with HAIs. The genus Copaifera, used in folk medicine due to its biological properties, stands out for its oleoresin production, with various pharmacological effects reported in the literature. Therefore, this study aimed to analyze the antimicrobial and antibiofilm activity of oleoresins extracted from C. arenicola (OCa) and C. langsdorffii (OCl) against S. aureus strains, as well as to evaluate their toxicity against cell lines (L929 and HaCaT) and Artemia salina. Regarding the results, both oleoresins showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values ​​between 125 and 500 μg/mL. For the non-volatile fractions of both species, the values ​​were 31.25 to 62.5 μg/mL for MIC and 31.25 to 125 μg/mL for MBC. For the major compounds, the concentrations ranged from 15.625 to 125 μg/mL for both MIC and MBC. The oleoresins also significantly inhibited biofilm formation, with reductions in viable cells ranging from 1 to 8.33 logs, a decline in biomass between 84.6 and 100%, and a decrease in metabolic activity between 67.80 and 100%. In pre-formed biofilms, reductions ranged from 0.71 to 2.71 logs of viable cells; decreases between 56.77% and 86.58% in total biomass; and from 17.77% to 92.62% in metabolic activity. Regarding Scanning Electron Microscopy, a reduction in cell quantity and extracellular matrix was observed, in addition to altered morphology after treatment with oleoresins in the CIM. In the cell viability assay, for both cell lines, the oleoresins showed cytotoxicity starting at a concentration of 250 μg/mL. Regarding A. salina, OCa showed a toxic effect starting at a concentration of 125 μg/mL, and OCl at 250 μg/mL. In light of the above, both oleoresins showed antibacterial and antibiofilm activity against the tested S. aureus strains, and most did not exhibit toxicity at concentrations lower than 250 μg/mL for the cell lines and A. salina. Thus, both oleoresins have promising potential against infections and biofilm formation associated with S. aureus