['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.', '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.', '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.'] Is α-Amylase a potential growth inhibitor of Porphyromonas gingivalis , a periodontal pathogenic bacterium?