Feruloyl esterase activity is influenced by bile, probiotic intestinal adhesion and milk fat.

Cinnamoyl esterases (CE) are microbial and mammalian intestinal enzymes able to release antioxidant hydroxycinnamic acids from their non-digestible ester-linked forms naturally present in vegetable foods. Previous findings showed that oral administration of Lactobacillus fermentum CRL1446 increased intestinal CE activity and improved oxidative status in mice. The aim of this work was to evaluate the in vitro CE activity of L. fermentum CRL1446 and the effect of bile on this activity, as well as strain resistance to simulated gastrointestinal tract (GIT) conditions and its ability to adhere to intestinal epithelium and influence its basal CE activity. L. fermentum CRL1446 and L. fermentum ATCC14932 (positive control for CE activity) were able to hydrolyse different synthetic hydroxycinnamates, with higher specificity toward methyl ferulate (3,853.73 and 899.19 U/g, respectively). Feruloyl esterase (FE) activity was mainly intracellular in L. fermentum CRL1446 and cell-surface associated in L. fermentum ATCC14932. Both strains tolerated simulated GIT conditions and were able to adhere ex vivo to intestinal epithelium. Pre-incubation of L. fermentum strains with bile increased FE activity in both whole cells and supernatants (~2-fold), compared to controls, suggesting that cells were permeabilised by bile, allowing more substrate to enter the cell and/or leakage of FE enzymes. Three-fold higher FE activities were detected in intestinal tissue fragments with adhered L. fermentum CRL1446 cells compared to control fragments (without bacteria), indicating that this strain provides exogenous FE activity and could stimulate esterase activity in the intestinal mucosa. Finally, we found that milk fat had a negative effect on FE activity of intestinal tissue, in absence or presence of adhered L. fermentum. These results help explaining the increase in intestinal FE activity previously observed in mice fed with L. fermentum CRL1446, and support the potential use of this strain for the development of new functional foods directed to oxidative stress-related ailments.

Administration of Lactobacillus fermentum CRL1446 increases intestinal feruloyl esterase activity in mice.

AIMS: To evaluate the effect of oral administration of Lactobacillus fermentum CRL1446 on the intestinal feruloyl esterase (FE) activity and oxidative status of mice. METHODS AND RESULTS: Adult Swiss albino mice received Lact. fermentum CRL1446 at the doses 10(7) and 10(9) cells per day per mouse for 2, 5, 7 and 10 days. Intestinal FE activity, intestinal microbiota counts, plasmatic thiobarbituric acid-reactive substances (TBARS) percentage and glutathione reductase (GR) activity were determined. Mice that received Lact. fermentum CRL1446 at the dose 10(7) cells per day for 7 days showed a twofold increase in total intestinal FE activity, compared to the nontreated group. In large intestine content, FE activity increased up to 6·4 times. No major quantitative changes in colonic microbiota were observed in treated animals. Administration of this strain produced an approx. 30-40% decrease in the basal levels of plasmatic TBARS and an approx. twofold increase in GR activity from day 5 of feeding with both doses. CONCLUSIONS: Oral administration of Lact. fermentum CRL1446 to mice increases total intestinal FE activity, decreases the basal percentage of plasmatic lipoperoxides and increases GR activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus fermentum CRL1446 could be orally administered as a dietary supplement or functional food for increasing the intestinal FE activity to enhance the bioavailability of ferulic acid, thus improving oxidative status.