Critical concentration of lecithin enhances the antimicrobial activity of eugenol against Escherichia coli

Haoshu Zhang, Edward G. Dudley, P. Michael Davidson, Federico Miguel Harte

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects.

Original languageEnglish (US)
Article numbere03467-16
JournalApplied and environmental microbiology
Volume83
Issue number8
DOIs
StatePublished - Apr 1 2017

Fingerprint

Eugenol
antimicrobial activity
Lecithins
eugenol
phosphatidylcholines
anti-infective agents
Escherichia coli
anti-infective properties
food
emulsion
absorbance
transmission electron microscopy
Cryoelectron Microscopy
Food
effect
emulsifiers
Emulsions
Transmission Electron Microscopy
oil
emulsions

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

Cite this

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title = "Critical concentration of lecithin enhances the antimicrobial activity of eugenol against Escherichia coli",
abstract = "Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050{\%} [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects.",
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Critical concentration of lecithin enhances the antimicrobial activity of eugenol against Escherichia coli. / Zhang, Haoshu; Dudley, Edward G.; Davidson, P. Michael; Harte, Federico Miguel.

In: Applied and environmental microbiology, Vol. 83, No. 8, e03467-16, 01.04.2017.

Research output: Contribution to journalArticle

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