In vitro antioxidant and immunomodulation capacities of low-molecular weight-alginate- and laminaran-responsible gut indigenous bacteria

This study was conducted to evaluate the combined effects of brown algal polysaccharides, low-molecular weight (LMW)-alginate and laminaran, and their responsible gut indigenous bacteria (RIB) on the host. The effects of the alginate- and laminaran-degrading bacterial strains isolated from caecum of mice (Bacteriocides acidifaciens PS4 and Bacteriocides intestinalis ALB-11) and human faeces (Bactroides xylanisolvens H-Alg-1, Bactroides uniformis H-Lam-1, Bactroides finegoldii JCM 13345T, and Erysipelatoclostridium ramosum JCM 1298T) on DPPH radical scavenging capacity and NO secretion from murine macrophage RAW264.7 cells were determined. The DPPH radical scavenging capacities of the culture with polysaccharides, particularly laminaran, was 1.8–12 times higher than that of the culture without polysaccharides. NO secretion was increased by 1.4–3.5 times from RAW264.7 cells by the bacterial cells (final optical density at 600 nm = 1.0) incubated with the polysaccharides, particularly LMW-alginate. The NO secretion induced by Escherichia coli O111 lipopolysaccharide was reduced by 34–57% in the culture supernatant incubated with laminaran. These results suggest that fermentable polysaccharides in brown algae have antioxidant and immunomodulation capacities in the gut environment composed of RIB, which may be useful for preventing lifestyle- and ageing-related diseases in the host.公開予定日: 2022-07-1