Lactic acid bacteria isolated from equid milk and their extracellular metabolites show great probiotic properties and anti-inflammatory potential

Traditionally, equid milk has been used as an alternative to human milk for infants or children mainly because of its similarities in nutrient composition, hypoallergenicity, immune modulation and antimicrobial activity. As a highly nutritious substrate, it possesses great potential for probiotic bacteria isolation. The aim of this study was to assess the probiotic potential of Lactobacillus plantarum M2 and L. plantarum KO9 isolated from donkey and mare milk, respectively, and determine TNF-α suppression attributed to their extracellular metabolites in lipopolysaccharide- (LPS-)stimulated human peripheral blood mononuclear cells (PBMCs). Resistance to simulated gastric and intestinal conditions, antimicrobial activity against pathogens, autoaggregation, coaggregation, biofilm quantification, antioxidative potential and haemolytic activity were determined. The isolated strains demonstrated great probiotic potential and their extracellular metabolites with molecular mass smaller than 2000 Da supressed TNF-α production up to 67% in LPS-stimulated PBMCs exerting high anti-inflammatory activity. Extracellular metabolites did not show any cyto/genotoxic effects toward PBMCs.