Screening and Identification of Anti-inflammatory Lactic Acid Bacteria from Sour Bamboo Shoot

Totally 46 strains suspected of being lactic acid bacterial were isolated from three samples of sour bamboo shoot collected in Liuzhou, and their probiotic and anti-inflammatory properties were evaluated by acid resistance, bile salt resistance, simulated gastrointestinal digestion, in vitro HT-29 cell adhesion and NO release tests. Strain SS-31 was selected as an excellent anti-inflammatory strain and it was identified as Lactobacillus fermentum by 16S rRNA gene sequencing. The results showed that SS-31 had high acid resistance, and the number of viable cells remained above 10⁷ CFU/mL with a survival rate of over 90.02% after 3 h of treatment with 0.1% bovine bile salt. Its survival rate was 80.28% after 2 h incubation in artificial gastric juice, but only 3.63% in simulated artificial gastric juice. SS-31 had strong adhesion to HT-29 cells with an adhesion rate of 4.47%, which was just slightly lower than that of the control strain Lactobacillus rhamnosus LGG (4.95%). Compared with the model group, SS-31 significantly reduced the secretion level of NO in the culture supernatant of lipopolysaccharide (LPS)-simulated RAW264.7 cells (P < 0.05), and pro-inflammatory cytokines such as IL-1β and IL-6 (P < 0.05). The results proved that Lactobacillus fermentum SS-31 has potential for the treatment of inflammation.