Linoleic acid inhibits Lactobacillus activity by destroying cell membrane and affecting normal metabolism

BACKGROUND The reason why dietary polyunsaturated fatty acids (PUFAs) affect the activity of Lactobacillus remains unclear. In this study, linoleic acid was used to study the mechanism underlying its inhibition function against Lactobacillus activity. RESULTS The growth curve of Lactobacillus rhamnosus LGG and the metabolite content in bacterial liquid were determined at varying linoleic acid concentration. The degree of cell membrane damage of L. rhamnosus LGG was determined by flow cytometry and fluorescence microscopy, and the cell structure was observed by scanning electron microscopy and transmission electron microscopy. The effect of linoleic acid on Lactobacillus activity was assessed in a simulated gut environment. Results showed that L. rhamnosus LGG grew slowly, cell metabolites leaked into the liquid, cell membrane was damaged, and the cell structure changed at a linoleic acid concentration of 50 mu g mL(-1). CONCLUSION The mechanism of action of linoleic acid on Lactobacillus showed that that linoleic acid destroyed the cell membrane of bacteria, thereby affecting the normal metabolism of the bacteria and ultimately leading to their death. (c) 2019 Society of Chemical Industry