ANTIOXIDANT COMPOUND RELEASE BY CINNAMOYL ESTERASES OF PROBIOTIC LACTIC ACID BACTERIA

M.I. RUSSO, L. SAAVEDRA, C. ABEIJÓN MUKDSI, P. GAUFFIN CANO, R. MEDINA

Córdoba

Congreso; XI CONGRESO ARGENTINO DE MICROBIOLOGIA GENERAL; 2015

Sociedad Argentina de Microbiología General

Hydroxycinnamicacids (HA), such as caffeic (CA), ferulic (FA), p-coumaric and sinapicacids, are commonly found in fruits, vegetables and grains ester-linked tovegetable cell wall polymers, and can not be absorbed under these complexforms. HA are phenolic compounds that exhibit antioxidant and chemoprotectiveproperties, and they are released by cinnamoyl esterase (CE) enzymes.Hydrolysis of ester bonds carried out by CE and the subsequent release of HA isthe first step required for the bioavailability and metabolism of these acids.CE were detected in human and animal intestinal mucosa and gut microbiota. Thereis few information about CE of probiotic lactic acid bacteria (LAB). The use ofprobiotic bacteria with CE activity able to stimulate the release ofantioxidant compounds in the gut, can be applied for treatment and/orprevention of pathologies associated with malnutrition. The aim of this studywas to detect CE activity in two probiotic LAB, and evaluate the release of antioxidantcompounds [ferulic acid (FA) and caffeic acid (CA)] from the hydrolysis ofhydroxycinnamates (HC) [ethyl ferulate (EF) and chlorogenic acid (ChA),respectively]. Lactobacillus fermentum CRL1446 and Lactobacillusacidophilus CRL1014, strains isolated from dairy products and humanintestine, respectively, were selected for their probiotic properties. CEactivity was evaluated on agarized MRS medium (with glucose omitted)supplemented with 4.5 mM ethyl ferulate (MRS-EF). Strains were streaked on themedium and incubated at 37 °C for 24 h. In addition, kinetics of HC consumptionand HA production by both strains were evaluated in MRS-EF and MRS-ChA brothmedia 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 and24 h of incubation, and culture supernatants were obtained by centrifugation(10000 rpm at 4 °C). HC and HA concentrations in supernatants were determined byHPLC. CE activity was detected in both strains by appearance of a clear zonearound 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, producing0.72 mM FA and 0.75 mM CA, respectively. The production rate was 0.032 mM/h forFA and 0.031 mM/h for CA. L. acidophilus CRL1014 also hydrolyzed all HCpresent in the media, releasing 1.15 mM FA and 0.75 mM CA. The production ratewas 0.097 mM/h forFA and 0.034 mM/h for CA. Released HA were not furthermetabolized by these strains, since no other metabolic products were detectedup to 48 h incubation. On the basis of these results, L. fermentum CRL1446and L. acidophilus CRL1014 can be proposed as potential probioticstrains able to release antioxidant HA. In vivo studies are beingcarried out to elucidate the effect of oral administration of these strains onthe host oxidative status in a murine model of malnutrition.