Effects of p-coumaric acid on Probiotic Properties of Lactobacillus acidophilus LA-5 and Lacticaseibacillus rhamnosus GG

Abstract

p-coumaric acid (p-CA) is one of the most abundant phenolic compounds in nature and human diet. Probiotic bacteria are microorganisms conferring health benefits on host when administered in adequate amounts. The synbiotic interaction of these two contents, found in gastrointestinal tract, and effect of this interaction on intestines are not known. Thus, this study aimed to investigate synbiotic relationship between p-CA and Lactobacillus acidophilus LA-5 (LA-5), Lacticaseibacillus rhamnosus GG (LGG). They were grown in the presence of different concentrations of p-CA and effects of p-CA on probiotic properties, as well as in vitro effects on AChE and BChE activities were examined. Results indicated p-CA did not negatively affect bacterial growth, but increased auto-aggregation of both probiotics. While p-CA increased co-aggregation of LA-5 and LGG against Escherichia coli, it decreased co-aggregation against Staphylococcus aureus. Probiotics grown with p-CA were more resistant to pepsin. While p-CA increased the resistance of LA-5 to bile salt, it decreased the resistance of LGG. The combinations of bacteria and p-CA efficiently suppressed AChE and BChE with inhibition (%) 11.31-68.06 and 13.47-65.14, respectively. Furthermore, surface analysis was conducted using FTIR to investigate the interaction of p-coumaric acid with LA-5 and LGG, and changes in cell components on the bacterial surface were analyzed. The results, recorded in range of 4000-600 cm⁻¹ with resolution of 4 cm⁻¹, demonstrated that p-CA significantly affected only the phosphate/CH ratio for both bacteria. These results indicate the addition of p-CA to the probiotic growth may enhance the probiotic properties of bacteria.