Antibacterial Effect of Eugenol on <i>Shigella flexneri</i> and Its Mechanism

<i>Shigella flexneri</i> (<i>Sh. flexneri</i>), which can be found in food and the environment, is a widespread food-borne pathogen that causes human diarrhea termed “shigellosis”. In this study, eugenol, a natural active substance, was investigated for its antibacterial acti...

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Bibliographic Details
Main Authors: Xiangyang Bai, Xuejiao Li, Xue Liu, Zeyu Xing, Ruiying Su, Yutang Wang, Xiaodong Xia, Chao Shi
Format: Article
Language:English
Published: MDPI AG 2022-08-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/11/17/2565
Description
Summary:<i>Shigella flexneri</i> (<i>Sh. flexneri</i>), which can be found in food and the environment, is a widespread food-borne pathogen that causes human diarrhea termed “shigellosis”. In this study, eugenol, a natural active substance, was investigated for its antibacterial activity against <i>Sh. flexneri</i>. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of eugenol against <i>Sh. flexneri</i> ATCC 12022 was 0.5 and 0.8 mg/mL. The growth curves and inhibitory effect in LB broth, PBS, vegetable juice, and minced pork showed that eugenol had a good activity against <i>Sh. flexneri</i>. Research findings indicated the superoxide dismutase activity of <i>Sh. flexneri</i> was inhibited after eugenol treatment, resulting in concentrations of intracellular reactive oxygen species and an increase in malondialdehyde. The flow cytometry analysis and field emission scanning electron microscopy results revealed obvious damage to cell membrane integrity and changes in the morphology of <i>Sh. flexneri</i>. In addition, the intracellular ATP concentration leaked from 0.5 μM to below 0.05 μM and the membrane potential showed a concentration-dependent depolarization after eugenol treatment. In summary, eugenol exerted strong antibacterial activity and has the potential to control <i>Sh. flexneri</i> in the food industry.
ISSN:2304-8158