Antimicrobial activity of peptide fractions from Mucuna pruriens against Escherichia coli and Listeria monocytogenes.

Abstract

In the present work, the inhibitory activity of bacterial growth of peptide fractions from the legume Mucuna pruriens obtained by sequential enzymatic hydrolysis of the protein concentrate of its grains was evaluated. Dry grains of Mucuna pruriens obtained in the Yucatán state from the 2015 crop were used. To obtain the concentrate, a wet fractionation of the components of the grain flour was carried out and subsequently hydrolyzed by two sequential enzymatic systems, Alcalase®-Flavourzyme® and Pepsin-Pancreatin. To obtain the peptide fractions an ultrafiltration process was performed using membranes with different molecular weight cut: 10, 5, 3 and 1 kDa. The degree of hydrolysis was 25.34 and 47.28%, for Alcalase®-Flavourzyme® and Pepsin-Pancreatin systems, respectively. The protein content of the peptide fractions ranged from 0.114-1.018 mg/mL for Alcalase®-Flavourzyme® and from 0.175-1.014 mg/mL for Pepsin-Pancreatin. The molecular weight of the peptide fractions was verified by SDS-PAGE denaturing electrophoresis and compared against commercial molecular markers. The strains evaluated were Escherichia coli O157: H7 and Listeria monocytogenes ATCC 19115. Antibiograms were performed on each microorganism to determine the sensitivity to known antibiotics. Disk diffusion tests were negative for the peptide fractions of both enzyme systems

Keywords

• Mucuna pruriens
• sequential hydrolysis
• ultrafiltration; peptide fractions
• antimicrobials