Radio-protective effect of polysaccharides isolated from Lactobacillus brevis-fermented Ecklonia cava

We investigated the radioprotective effects of a polysaccharide isolated from enzymatic extracts of Ecklonia cava (E. cava) fermented by fungi and bacteria. We identified that the aqueous extract of the Lactobacillus brevis-fermented E. cava especially showed the highest proliferation effect. In addition, the enzymatic extract prepared by enzyme-assisted extraction using Viscozyme (VLFE) significantly increased cell proliferation. Further study indicated that the polysaccharides isolated from the >30 kDa fraction of VLFE (VLFEP) significantly enhanced survival and proliferation effects in γ-ray-irradiated cells. Also, VLFEP markedly reduced the DNA damage, production of reactive oxygen species, and the percentage of Sub-G1 DNA contents caused by γ-ray-irradiation. Moreover, VLFEP modulated the expression levels of p53, Bax, and Bcl-2 via inhibition of IκBα degradation and phosphorylation and NFκB p65 translocation into nuclei. These results demonstrate that VLFEP has radioprotective properties including the modulation of apoptosis via the inhibition of the NFκB signaling pathway.