Erythrina velutina, is a tree native to Brazil, known for its medicinal properties and easily
found in the Northeast of the country, this plant is rich in alkaloids and flavonoids. The
ethanolic extract of Erythrina velutina has gained more and more space, mainly due to its
anxiolytic potential. In this sense, the objective of the present study was to evaluate the
antibacterial potential of Mulungu leaf extract (Erythrina velutina) in strains of bacteria that
cause various pathologies in humans. For this, extracts of the leaves of the plant in good
condition, free of any deficiency and/or with signs of parasitism, were obtained, which were
cataloged and labeled in plastic bags for further processing in the laboratory. The leaves of the
species underwent numerous processes to reach the final result of the crude extract, which was
used to evaluate the antibacterial activity of E.velutina leaves against clinical strains. The
bacterial strains used came from standardized American Type Cell Culture (ATCC) collections,
properly characterized morphologically, physiologically and biochemically, performed with

Gram positive bacteria: saprophytic Staphylococcus, Staphylococcus aureus, and Gram-
negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris and Klebsiella

pneumoniae. Initially, all strains were reactivated in Brain Heart Infusion –BHI broth for 24 h
to obtain turbidity equivalent to the standard 0.5 on the Mac Farland scale, which corresponds
to a concentration of approximately 1.5 x 108 CFU/mL. Subsequently, antibiotics were used to
use the positive control (C+) to inhibit bacterial growth and, as a negative control, 20 μL of
distilled water. For analysis of the antibacterial potential of the extracts, the well technique with
modifications was used. The results were read by checking the diameters of the halos in
millimeters (mm), formed around the wells containing the extracts. Regarding the extract of
Erythrina velutina, it was analyzed that there was no antimicrobial sensitivity in the strains, as
there were no growths of halos in the petri dishes, in any of the concentrations in which there
was dilution of the solid extract (4, 8, 16 and 32 mg. mL- 1). During the execution of the
experimental stage, it was noticed that there was antimicrobial sensitivity only in the positive
control group (C+). In view of this, it was possible to analyze that there was no antibacterial
sensitivity in any of the strains tested, and it can be concluded that, according to the
methodology used in this work, Erythrina velutina did not present antimicrobial potential
against the strains tested within the concentrations used, thus, it was only possible to observe
sensitivity against the antibiotics used for the control group. However, it is suggested that more
research be carried out in order to investigate whether there is antibacterial potential of extracts
made from other parts of the plant, in order to corroborate the data with existing studies in the
literature and the findings in this research.