Atividade antimicrobiana in vitro de extratos de plantas medicinais sobre patógenos de origem alimentar (Escherichia coli, Staphylococcus aureus e Salmonella Typhimurium)

Abstract

Pathogens foodborne are one of the most important problems in public health in the world, responsible for losses with medical costs, morbidity and mortality. The emergence of microbial strains resistant to a wide variety of antibiotics have exacerbated the problem, highlighting the need for discovery of new compounds with antimicrobial activity. Thus, the aim of this study was to evaluate the phytochemical profile and antimicrobial potential in vitro of plant extracts of three medicinal plants collected in Tocantins State on often microorganisms related to food poisoning. Leaf samples were collected and inner bark of Parkia platycephala Benth, Pouteria ramiflora (Mart.) Radlk and Lophantera lactescens Ducke and elaborate hydroalcoholic and aqueous extracts of vegetables. The extracts were subjected to phytochemical evaluation for the identification of their bioactive compounds, solubilized in dimethyl sulfoxide solution (DMSO) at 1% concentration 25 mg/mL, stock solution, for the antimicrobial activity test, which were determined minimum inhibitory concentration (MIC) and bactericidal concentration Minimum (CBM) by microdilution techniques in broth and bacterial growth observation on agar plates Mueller Hinton, respectively, using extracts concentrations of 12.5; 6.25; 3.12; 1.56; 0.78; 0.39; 0.19 and 0.09 mg / mL front strains of Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Salmonella Typhimurium ATCC 14028. The results of the phytochemical analysis revealed that extracts of the leaves of the species L. lactescens obtained were smaller the presence of bioactive compounds in its composition, organic acids, tannins and saponins, while the inner bark of the species and other plants also showed the compounds catechins, sesquiterpenlactonas and anthraquinones, the latter except in the species P. plathycephala. The antimicrobial activity of the three species of plants had become active, with S. aureus more susceptible microorganism to the extracts. E. coli and Salmonella were inhibited only with extracts application of the inner bark of P. plathycephala. Thus, it was concluded that the three species of plants evaluated have shown to be promising for the development of new products with antimicrobial activity, and the specie P. plathycephala presented a greater spectrum of action.