Selected Lactobacillus bulgaricus and Streptococcus thermophilus Strains from Bulgarian Yogurt Demonstrate Significant AntiInflammatory Potential

In vitro tests for establishing the anti-inflammatory potential of twenty-two previously selected Lactic acid bacteria (LAB) strains were carried out. The aim was to compare the antiinflammatory potential of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus isolated from authentic homemade yogurt in non-industrial mountain villages in Bulgaria with selected strains originated from the intestinal tract of healthy volunteers. The assessed signal peptide associated with inflammation was IL-8, with and without stimulation of TNF-alpha, in order to simulate inflammatory shock in vitro. To establish the antiinflammatory potential of the strains, two cytokines with predominant anti-inflammatory effects, IL-10 and TGF-beta were evaluated as well. The different cytokines were evaluated using three different analytical models, including mice splenocytes. Among the presented strains of intestinal origin only two Lactobacillus gasseri, one Enterococcus faecium and one Bifidobacterium longum possessed simultaneously the desirable optimal cytokine profile, where the highest induction of IL-10 was 1670.2 pg/ml (E. faecium 2092/2); the strongest reduction of IL-8 was 46.9 pg/ml (B. longum 10/48) and the induction of TGF-ß varied between 548.75 and 834.53 pg/ml. Among the strains of yogurt origin, three Lactobacillus bulgaricus and three Streptococcus thermophilus possessed concurrent or even better anti-inflammatory profiles, where the highest induction of IL-10 was 1584.1 pg/ml (L. bulgaricus b58); the strongest reduction of IL-8 was 46.0 pg/ml (Str. thermophilus T43) and the induction of TGF-ß varied between 499.96 and 841.50 pg/ml.