Antibacterial effects of Annona muricata ethanolic extract on clinically important microorganisms

Abstract

The increase in pathogenic strains resistant to conventional drugs has limited medical treatment options. Given this, the need to seek therapeutic alternatives arises. Many plant species have enormous antimicrobial potential that can be very useful. Objective: to determine in vitro the antibacterial effect of the ethanolic extract of Annona muricata L. on Staphylococcus aureus, Streptococcus B - hemolytic and Escherichia coli. Methods: 135 experimental units were evaluated, consisting of 3 strains of Staphylococcus aureus, Streptococcus B-hemolytic and Escherichia coli, in addition to 5 concentrations of the extract and 3 repetitions of the experiment. To determine the antibacterial effect in vitro, the agar diffusion disk and broth macrodilution methods were used. The ethanolic extract was used at concentrations of 125, 250, 500, 750, 1000 mg / ml and sterile physiological saline solution as negative control. Results: the extract inhibited in vitro growth of Staphylococcus aureus and Streptococcus B-hemolytic. The greatest inhibition was observed at 1000 mg / ml with inhibitory halos of 14.6 mm and 12.33 mm in diameter, respectively. For Escherichia coli the formation of inhibitory halos was not observed. The Streptococcus B-hemolytic and Staphylococcus aureus strains presented a minimum inhibitory concentration of 250 and 500 mg / ml, respectively. Conclusion: the in vitro antibacterial effect was directly proportional to each concentration used on the Staphylococcus aureus and Streptococcus B-hemolytic. In the case of Escherichia coli, no growth inhibition was observed.