Department of Molecular Biology, University of León, Campus de Vegazana, León, Spain.
Department of Food Hygiene and Technology, University of León, Campus de Vegazana, León, Spain.
Foodborne Pathog Dis. 2019 Sep;16(9):622-629. doi: 10.1089/fpd.2018.2594. Epub 2019 Apr 19.
Plant and essential oil extracts have been used for some time as antimicrobials and antioxidants, although little is known about the interactions between the main components of these plant materials. This knowledge could help to design more potent antimicrobial and antioxidant mixtures. Carvacrol and thymol, the main components of the essential oils of the Lamiaceae family of plants, were assessed in combination to evaluate their antioxidant activity and antimicrobial effect against 19 strains of () of different origins (clinical, meat, milk, and other) and mostly (12) enterotoxin producers. The microdilution test assay was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the two phenolics alone and in combination. Based on the fractional inhibitory concentration index (FICI), no antimicrobial interaction (0.5 < FICI <4) between carvacrol and thymol was observed against 42% of the strains and an antagonistic interaction (FICI >4) was observed in the rest, which indicates different behavior among strains in relation to this antimicrobial combination. Particularly, an antagonistic effect was observed in 29% of the meat origin strains and 57% of the dairy origin strains. Combinations of carvacrol and thymol were bactericidal (differences in MIC and MBC values not more than twofold) for 60% of the tested strains. At low concentrations of both components, the antioxidant effect is additive. However, at high concentrations (2.50 or 2.66 mM) of at least one of the components of the combination, it is antagonistic. The different types of interactions of the components in the combination can depend on many factors (ratio, structural characteristics, and the establishment of intermolecular complexes). The results could be used as reference to apply this combination in foods to control , to maintain the organoleptic properties and to extend the shelf-life of them.
植物和精油提取物作为抗菌剂和抗氧化剂已经使用了一段时间，尽管人们对这些植物材料的主要成分之间的相互作用知之甚少。这种知识可以帮助设计更有效的抗菌和抗氧化混合物。香芹酚和百里香酚是唇形科植物精油的主要成分，它们被评估为组合使用，以评估它们的抗氧化活性和对不同来源（临床、肉类、牛奶和其他）的 19 株 （）的抗菌效果和主要（12）产肠毒素。微量稀释试验法用于单独和组合测定两种酚类化合物的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。根据部分抑菌浓度指数（FICI），在 42%的 菌株中，香芹酚和百里香酚之间没有观察到抗菌相互作用（0.5 < FICI < 4），而在其余菌株中观察到拮抗相互作用（FICI > 4），这表明该抗菌组合在菌株之间表现出不同的行为。特别是，在 29%的肉类来源菌株和 57%的乳制品来源菌株中观察到拮抗作用。香芹酚和百里香酚的组合对 60%的测试菌株具有杀菌作用（MIC 和 MBC 值的差异不超过两倍）。在两种成分的低浓度下，抗氧化作用是相加的。然而，在组合中至少一种成分的高浓度（2.50 或 2.66 mM）下，其作用是拮抗的。组合中成分的不同类型的相互作用可能取决于许多因素（比例、结构特征和分子间复合物的建立）。这些结果可作为参考，将该组合应用于食品中以控制 ，保持它们的感官特性并延长其保质期。
