Antimicrobial activity of the aqueous extract and fractions from the leaf of the aroeira-do-sertão

The plants popularly used in the treatment of various diseases, such as Myracrodruon urundeuva Allemão, have been investigated about the action on microorganisms, aiming the discovery and use of new natural additives. This research aimed to evaluate the in vitro antimicrobial activity of the aqueous extract of Myracrodruon urundeuva leaves and its fractions on pathogenic bacteria associated with foodborne diseases. The aqueous extract was obtained by decoction of the fresh leaves and fractionated by high-speed counter-current chromatography. The antimicrobial activity was performed using microdilution in a plate. The aqueous extract of “aroeira-do-sertão” leaves was effective against all tested microorganisms. Antimicrobial activity was verified for Staphylococcus aureus and Listeria monocytogenes (0.2 and 0.8 mg/mL, respectively) and for Salmonella Enteritidis, Pseudomonas aeruginosa, and Escherichia coli (6, 10 and 16 mg/mL respectively). Twenty-four secondary compounds were isolated, distributed in six fractions. The fractions showed antimicrobial activity on Gram-positive bacteria at low concentrations (0.011 to 0.095 mg/mL) and at higher concentrations (2.4 to 33 mg/mL), two fractions showed activity on Gram-negative bacteria. The union of the compounds in the extract was favorable for antimicrobial activity on all the studied bacteria, demonstrating that the susceptibility of the microorganisms to the extract varied according to the chemical compounds present.