Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
J Appl Microbiol. 2011 Nov;111(5):1176-84. doi: 10.1111/j.1365-2672.2011.05141.x. Epub 2011 Sep 20.
To determine structure-function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB).
Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p-coumaric, ferulic, protocatechuic or p-hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC-DAD-MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain-specific metabolism of phenolic acids generally corresponded to resistance.
The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids.
Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.
确定抗菌酚酸及其由乳酸菌产生的代谢物的结构-功能关系。
以植物乳杆菌、哈氏乳杆菌、大肠杆菌和枯草芽孢杆菌为指示菌株，测定 6-羟基苯甲酸和 6-羟基肉桂酸的最小抑菌浓度（MIC）。酚酸的抗菌活性在较低 pH 值下增加。羟基数量的减少增强了羟基苯甲酸的活性，但对羟基肉桂酸的影响较小。用甲氧基取代羟基增加了羟基苯甲酸的活性，但对羟基肉桂酸没有影响。通过 LC-DAD-MS 分析了绿原酸、咖啡酸、对香豆酸、阿魏酸、原儿茶酸或对羟基苯甲酸由植物乳杆菌、哈氏乳杆菌、发酵乳杆菌和雷特氏乳杆菌代谢的情况。此外，还比较了底物和代谢物的 MIC。酚酸的脱羧基和/或还原代谢物的活性低于底物。酚酸的菌株特异性代谢通常与耐药性相对应。
亲脂性对羟基苯甲酸的抗菌活性的影响强于羟基肉桂酸。LAB 对酚酸的代谢使酚酸解毒。
研究结果允许有针对性地选择植物提取物用于食品保鲜，并选择发酵产品的起始培养物。
