Antibacterial activity of proteins extracted from the pulp of wild edible fruit of Bromelia pinguin L.

Bromelia pinguin L. is a natural source of bioactive compounds. The main purpose of this research was to isolate and characterize bioactive proteins from its fruit. B. pinguin proteins were fractionated by gel filtration chromatography, and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antibacterial activity of the proteins was analyzed against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, and the enzymatic activity was evaluated by protease activity and trypsin inhibitions assays. Protein fraction obtained by gel filtration chromatography exhibited antibacterial activity against E. coli (minimum inhibitory concentration [MIC] 0.3492 mg/mL) and S. aureus (MIC 0.6845 mg/mL). The proteolytic activity of the fraction was 0.985 U_cas/mL. The substrate-sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay detected protease inhibitors with molecular weights of 43 and 74 kDa. Antibacterial studies of E.coli and S. aureus were determined by comparing the protein fraction with different antibiotics. The antibacterial activity of proteins extracted from the pulp of the fruit of Bromelia pinguin L. could be related to the presence of enzymes, protease inhibitors and peptides.