In vitro antioxidant and anti-inflammation properties of lactic acid bacteria isolated from fish intestines and fermented fish from the Sanriku Satoumi region in Japan

- 75 LAB isolated from Sanriku Satoumi coastal area in northeast Japan.
- 6 LAB strains increased clearly antioxidant capacities in their cultured broth.
- The strains protected human enterocyte like HT-29 from H2O2 toxicity.
- Lb. plantarum S-SU1 and Lc. lactis S-SU2 are considered as potentially starters.
- Lb. plantarum S-SU5 and P. pentosaceus S-SU6 are considered as functional cultures.

The Ministry of the Environment, Government of Japan, defines a Satoumi as a coastal area where biological productivity and biodiversity has increased through human interaction. As a way to identify new starters and probiotics, we isolated and screened lactic acid bacteria (LAB) with acid, bile, and salt resistance from the intestines of 23 fish and 11 fermented fish samples obtained from the northeastern (Sanriku) Satoumi region of Japan. Of the 301 isolates, 75 strains were selected as LAB, 6 of which clearly showed increased antioxidant activities (DPPH and O2− radical scavenging and Fe-reducing power) in their cultured broth. Four isolates (S-SU1, 3-5) were identified as Lactobacillus plantarum. The two other strains (S-SU2, 6) identified were Lactococcus lactis and Pediococcus pentosaceus. In these in vitro assays, Lc. lactis S-SU2, isolated from sea pineapple kimchi showed the highest radical scavenging capacity. Moreover, the protective effect of heat-killed cells against the toxicity of 3 mM H2O2 on Saccharomyces cerevisiae was the highest for Lb. plantarum S-SU1 isolated from a salted squid product, followed by P. pentosaceus S-SU6 isolated from the intestines of blue mackerel. Furthermore, Lb. plantarum S-SU5 showed inhibitory effect against the toxicity of 3 mM H2O2 in human enterocyte-like HT-29-luc cells and on nitrite (NO) production in mouse RAW264.7 macrophage cells, which was induced by Escherichia coli O111 lipopolysaccharide (LPS). These results suggest that the selected LAB strains are potential starters and/or functional components with antioxidant and anti-inflammatory properties.