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Evaluation of Combined Antibacterial Effects of Eugenol, Cinnamaldehyde, Thymol, and Carvacrol against E. coli with an Improved Method
Author(s) -
Pei Ruisong,
Zhou Feng,
Ji Baoping,
Xu Jing
Publication year - 2009
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2009.01287.x
Subject(s) - thymol , carvacrol , eugenol , cinnamaldehyde , chemistry , minimum inhibitory concentration , menthol , preservative , food science , chromatography , antimicrobial , essential oil , biochemistry , organic chemistry , catalysis
In this study, the antibacterial activities of eugenol, cinnamaldehyde, thymol, carvacrol, and their combinations against E. coli were investigated separately. First, broth macro‐dilution assay was adopted to determine the minimal inhibitory concentration (MIC) of the 4 components. Second, the combination testing was performed using chequerboard method. Finally, the combined effects were evaluated with an improved method, which was based on the indices of fractional inhibitory concentration (FIC) and Effect of the Combination (EC) jointly. The results indicated that MICs of the 4 components were 1600, 400, 400, and 400 mg/L, respectively; treatments with cinnamaldehyde/eugenol, thymol/eugenol, carvacrol/eugenol, and thymol/carvacrol revealed synergistic effects according to the 2 indices. By means of combination, MICs of eugenol, cinnamaldehyde, thymol, and carvacrol decreased to 400, 100, 100, and 100 mg/L, respectively. Consequently, the negative impacts of unpleasant smell of these 4 components could be minimized, making it possible to add them to foods as preservatives. In addition, this improved evaluation method provided a more accurate and comprehensive way to evaluate combined effects.