Biological characteristics and probiotic effect of Loigolactobacillus coryniformis Lc7

Abstract:

[Objective] To characterize the Loigolactobacillus coryniformis Lc7 isolated from feces of healthy adults and evaluate its probiotic effect. [Methods] Phylogenetic tree was constructed based on the 16S rRNA gene and the core genes of the genome for taxonomic identification of the strain. The tolerance to acid, bile salt tolerance, adhesion, antioxidant activity, and antibacterial activity were tested, and the hemolysis, gelatinase activity, and antimicrobial susceptibility of Lc7 were examined to evaluate the probiotic property. In addition, ulcerative colitis was induced in mice to assess the in vivo anti-inflammatory potential of the strain. [Results] Lc7 was identified as L. coryniformis. The survival rate of this strain was up to 70.17% at pH 3.0 and in the presence of 0.3% bile salt. The adhesion index of Lc7 to HT-29 cells was 56.33 CFU/cell while self-aggregation and hydrophobicity were 80% and 40%, respectively. Lc7 inhibited the growth of seven common pathogens including Shigella flexneri and Salmonella typhimurium. Moreover, it scavenged 91.70% and 48.53% of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and hydroxyl radicals (·OH), respectively. Lc7 showed no hemolysis or gelatinase activity and was sensitive to the antibiotics tested. In the experiment on colitis mice, Lc7 group had longer colons than the model group (P<0.01). In addition, Lc7 alleviated colonic lesions (P<0.01), decreased serum pro-inflammatory cytokines TNF-α and IL-1β, and increased serum anti-inflammatory cytokines IL-10 (P<0.01). [Conclusion] Lc7 has probiotic and anti-inflammatory properties, which can be further developed as a probiotic.