Antibacterial mechanism of Myagropsis myagroides extract on Listeria monocytogenes

The ethanol extract of Myagropsis myagroides had antimicrobial activity against Gram-positive bacteria. The extract was fractionated through liquid–liquid extraction; the chloroform fraction had strong antimicrobial activity against Listeria monocytogenes (minimum inhibitory concentration (MIC) 0.063 mg/mL), and Clostridium perfringens (MIC 0.031 mg/mL). The chloroform fraction was separated into 22 sub-fractions using silica gel column chromatography, with the fourth fraction (CH4) possessing the strongest antimicrobial activity against Gram-positive bacteria. Leakage of 260 nm-absorbing material and ATP was observed in CH4-treated cells and morphological alterations were observed by electron microscopy. These results indicate that the cytoplasmic membrane may be a target of the CH4 fraction.