α‐Amylase is a potential growth inhibitor of <i><scp>P</scp>orphyromonas gingivalis</i>, a periodontal pathogenic bacterium

Abstract

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis is a major etiological agent in the development and progression of periodontal diseases. In this study, we isolated a cell growth inhibitor against P. gingivalis species from rice protein extract. MATERIAL AND METHODS: The cell growth inhibitor active against P. gingivalis was purified from polished rice extract using a six-step column chromatography process. Its antimicrobial properties were investigated through microscope analysis, spectrum of activity and general structure. RESULTS: The inhibitor was identified as AmyI-1, an α-amylase, and showed significant cell growth inhibitory activity against P. gingivalis species. Scanning electron microscopy micrograph analysis and bactericidal assay indicated an intriguing possibility that the inhibitor compromises the cell membrane structure of the bacterial cells and leads to cell death. Moreover, α-amylases from human saliva and porcine pancreas showed inhibitory activity similar to that of AmyI-1. CONCLUSIONS: This is the first study to report that α-amylases cause cell death of periodontal pathogenic bacteria. This finding highlights the potential importance and therapeutic potential of α-amylases in treating periodontal diseases.