In vitro antibacterial activity and mechanism of monocaprylin against escherichia coli and staphylococcus aureus

Jianyu Wang, Maomao Ma, Jun Yang, Long Chen, Ping Yu, Jun Wang, Deming Gong, Shuguang Deng, Xuefang Wen, Zheling Zeng

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

In the present study, the antibacterial activity of monocaprylin in comparison with sodium benzoate and potassium sorbate against Staphylococcus aureus and Escherichia coli was assessed by measuring MIC, MBC, effect of pH on MIC, and incubation temperature on bactericidal efficacy. Results showed that monocaprylin exhibited an excellent antibacterial activity against both strains, with the lowest MIC and MBC of 1.28 mg/mL. A MIC of monocaprylin remained unchanged despite the pH values of culture medium, ranging from 5 to 9, unlike that of potassium sorbate or sodium benzoate. Furthermore, monocaprylin at MBC effectively reduced the population of E. coli and S. aureus by >5.5 log CFU/mL at 258C within 6 h and decreased E. coli by approximately 5.0 log CFU/mL and S. aureus by 2.9 log CFU/mL at 12 h. The underlying mechanism of monocaprylin was then investigated by measuring β-galactosidase activity, membrane potential, release of cellular contents, scanning electron microscopy, and transmission electron microscopy observations. Results indicated that monocaprylin killed E. coli by the rapid change in permeability and integrity of cell membrane, leading to decline of membrane potential, leakage of nucleic acids and proteins, and ultimately cell membrane disintegration and lysis. On the other hand, monocaprylin might exert its antibacterial activity against S. aureus mainly by diffusing across the cell wall, collapsing the cell membrane, and disturbing the order of intracellular contents. These findings indicated that monocaprylin had better antibacterial ability compared with traditional synthetic preservatives and might be a potential antibacterial additive independent of pH.

Original languageEnglish (US)
Pages (from-to)1988-1996
Number of pages9
JournalJournal of Food Protection
Volume81
Issue number12
DOIs
StatePublished - Dec 2018

Keywords

  • Antibacterial activity
  • Escherichia coli
  • Monocaprylin
  • Staphylococcus aureus
  • Underlying mechanism

ASJC Scopus subject areas

  • Food Science
  • Microbiology

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