Fan Xuetong, Wagner Karen, Sokorai Kimberly J B, Ngo Helen
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
J Food Prot. 2017 Jan;80(1):6-14. doi: 10.4315/0362-028X.JFP-16-080.
Novel phenolic branched-chain fatty acids (PBC-FAs) were evaluated for their antimicrobial properties against both gram-positive ( Listeria innocua , Bacillus subtilis , Enterococcus faecium ) and gram-negative ( Escherichia coli , Salmonella Typhimurium, and Pseudomonas tolaasii ) bacteria. In addition, PBC-FA derivatives, such as PBC-FA methyl ester mixture, methyl-branched fatty acid mixtures, and trimethylsilyl-PBC-FA methyl esters, were synthesized to study the structure activity relationship. Results showed that PBC-FAs were a potent antimicrobial against gram-positive bacteria with MICs of 1.8 to 3.6 μg/ml. The compounds were less effective against gram-negative bacteria. Derivatives of PBC-FAs and an equimolar mixture of oleic acid and phenol all had MICs above 233 μg/ml against both gram-positive and gram-negative bacteria. Comparison of antimicrobial activities of the PBC-FAs with those of the derivatives suggests that the carboxylic group in the fatty acid moiety and the hydroxyl group on the phenol moiety were responsible for the antimicrobial efficacy. Growth curves of L. innocua revealed that PBC-FAs prevented bacterial growth, while MBC-FAs only delayed the onset of rapid growth of L. innocua . Our results demonstrated that the novel PBC-FAs have potential for use as antimicrobials against gram-positive bacteria.
对新型酚类支链脂肪酸（PBC-FAs）针对革兰氏阳性菌（无害李斯特菌、枯草芽孢杆菌、粪肠球菌）和革兰氏阴性菌（大肠杆菌、鼠伤寒沙门氏菌和托拉氏假单胞菌）的抗菌性能进行了评估。此外，合成了PBC-FA衍生物，如PBC-FA甲酯混合物、甲基支链脂肪酸混合物和三甲基硅烷基-PBC-FA甲酯，以研究构效关系。结果表明，PBC-FAs对革兰氏阳性菌具有强效抗菌活性，最低抑菌浓度（MIC）为1.8至3.6μg/ml。这些化合物对革兰氏阴性菌的效果较差。PBC-FAs的衍生物以及油酸和苯酚的等摩尔混合物对革兰氏阳性菌和革兰氏阴性菌的MIC均高于233μg/ml。PBC-FAs与衍生物的抗菌活性比较表明，脂肪酸部分的羧基和苯酚部分的羟基对抗菌效果起作用。无害李斯特菌的生长曲线显示，PBC-FAs可阻止细菌生长，而MBC-FAs仅延迟无害李斯特菌快速生长的起始。我们的结果表明，新型PBC-FAs有潜力用作抗革兰氏阳性菌的抗菌剂。
