ANTIOXIDANT COMPOUND RELEASE BY CINNAMOYL ESTERASES OF PROBIOTIC LACTIC ACID BACTERIA

RUSSO MATIAS I; SAAVEDRA LUCILA; ABEIJÓN MUKDSI MARÍA C.; GAUFFIN CANO MARÍA P. ; MEDINA ROXANA

Córdoba

Congreso; XI Congreso Argentino de Microbiología General SAMIGE 2015; 2015

SAMIGE - Asociación Civil de Microbiología General

Hydroxycinnamic acids (HA), such as caffeic (CA), ferulic (FA), p-coumaric and sinapic acids, are commonly found in fruits, vegetables and grains ester-linked to vegetable cell wall polymers, and can not be absorbed under these complex forms. HA are phenolic compounds that exhibit antioxidant and chemoprotective properties, and they are released by cinnamoyl esterase (CE) enzymes. Hydrolysis of ester bonds carried out by CE and the subsequent release of HA is the first step required for the bioavailability and metabolism of these acids. CE were detected in human and animal intestinal mucosa and gut microbiota. There is few information about CE of probiotic lactic acid bacteria (LAB). The use of probiotic bacteria with CE activity able to stimulate the release of antioxidant compounds in the gut, can be applied for treatment and/or prevention of pathologies associated with malnutrition. The aim of this study was to detect CE activity in two probiotic LAB, and evaluate the release of antioxidant compounds [ferulic acid (FA) and caffeic acid (CA)] from the hydrolysis of hydroxycinnamates (HC) [ethyl ferulate (EF) and chlorogenic acid (ChA), respectively]. Lactobacillus fermentum CRL1446 and Lactobacillus acidophilus CRL1014, strains isolated from dairy products and human intestine, respectively, were selected for their probiotic properties. CE activity was evaluated on agarized MRS medium (with glucose omitted) supplemented with 4.5 mM ethyl ferulate (MRS-EF). Strains were streaked on the medium and incubated at 37 °C for 24 h. In addition, kinetics of HC consumption and HA production by both strains were evaluated in MRS-EF and MRS-ChA broth media containing 1.5 mM EF or ChA, respectively. Strains were inoculated at 2% (v/v) and incubated at 37 °C for 24 h. Samples were taken at 0, 3, 6, 9, 12 and 24 h of incubation, and culture supernatants were obtained by centrifugation (10000 rpm at 4 °C). HC and HA concentrations in supernatants were determined by HPLC. CE activity was detected in both strains by appearance of a clear zone around the colonies grown on MRS-EF plates. At the end of incubation period, L. fermentum CRL1446 hydrolyzed all EF and ChA present in the media, producing 0.72 mM FA and 0.75 mM CA, respectively. The production rate was 0.032 mM/h for FA and 0.031 mM/h for CA. L. acidophilus CRL1014 also hydrolyzed all HC present in the media, releasing 1.15 mM FA and 0.75 mM CA. The production rate was 0.097 mM/h for FA and 0.034 mM/h for CA. Released HA were not further metabolized by these strains, since no other metabolic products were detected up to 48 h incubation. On the basis of these results, L. fermentum CRL1446 and L. acidophilus CRL1014 can be proposed as potential probiotic strains able to release antioxidant HA. In vivo studies are being carried out to elucidate the effect of oral administration of these strains on the host oxidative status in a murine model of malnutrition.