Effect of Lactobacillus acidophilus Fermented Broths Enriched with Eruca sativa Seed Extracts on Intestinal Barrier and Inflammation in a Co-Culture System of an Enterohemorrhagic Escherichia coli and Human Intestinal Cells.

Francesca Bonvicini,Eleonora Pagnotta,Mara Mirasoli,Angela Punzo,Giovanna Angela Gentilomi,Aldo Roda,Donato Calabria,Luisa Ugolini,Serena Bertoni,Nadia Passerini,Patrizia Simoni,Cristiana Caliceti,Luca Lazzeri

doi:10.3390/nu12103064

Abstract

Lactic acid bacteria (LAB) “fermentates” confer a beneficial effect on intestinal function. However, the ability of new fermentations to improve LAB broth activity in preventing pathogen-induced intestinal inflammation and barrier dysfunction has not yet been studied. The objective of this study was to determine if broths of LAB fermented with Eruca sativa or Barbarea verna seed extracts prevent gut barrier dysfunction and interleukin-8 (CXCL8) release in vitro in human intestinal Caco-2 cells infected with enterohemorrhagic Escherichia coli (EHEC) O157:H7. LAB broths were assayed for their effects on EHEC growth and on Caco-2 viability; thereafter, their biological properties were analysed in a co-culture system consisting of EHEC and Caco-2 cells. Caco-2 cells infected with EHEC significantly increased CXCL8 release, and decreased Trans-Epithelial Electrical Resistance (TEER), a barrier-integrity marker. Notably, when Caco-2 cells were treated with LAB broth enriched with E. sativa seed extract and thereafter infected, both CXCL8 expression and epithelial dysfunction reduced compared to in untreated cells. These results underline the beneficial effect of broths from LAB fermented with E. sativa seed extracts in gut barrier and inflammation after EHEC infection and reveal that these LAB broths can be used as functional bioactive compounds to regulate intestinal function.

Highlights

The use of microbial fermenters has been instrumental in making a large range of foods, popular around the world
The present study examined the biological properties of three bacterial broths obtained by lactobacilli fermentation alone (A1), in presence of E. sativa (A2), or B. verna (A3)
The broth obtained by L. acidophilus fermentation in the presence of enriched extracts from E. sativa seeds, characterized by a high concentration of glucoerucin, induced a significant decrease in the CXCL8 expression in Caco-2 cells following Escherichia coli (EHEC) infection, and reduced epithelial disruption caused by EHEC when intestinal cells were cultured to form a fully differentiate, confluent and tight monolayer

Summary

Introduction

The use of microbial fermenters has been instrumental in making a large range of foods, popular around the world. Lactobacilli fermented cruciferous vegetables are often rich in other functional ingredients such as garlic, ginger, and red pepper powder which are themselves very rich in vitamins, minerals, and dietary fibres [4,5]. Fermentation is considered to be a major factor responsible for the favourable effects of Brassicaceae vegetables in improving overall food quality, few evidences supporting this concept have yet been reported. Fermentation can be regulated in order to enhance the content of vitamin B12 [6], or vitamin C [7], depending on the starting fresh vegetable, the bacterial inoculum, and the presence of other ingredients. More recently Odongo et al studied the differences in composition of secondary plant metabolites in raw, fermented, and cooked Brassica carinata leaves, highlighting a sharp decrease in glucosinolate (GSL), a unique class of plant secondary metabolites [8], a structure-dependent degradation of phenolic compounds in fermented products in comparison to fresh leaves, and a slight increase in isothiocyanates, i.e. GSL hydrolysis products, in comparison to both raw and cooked vegetable materials [9]

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