Antioxidant activity of exopolysaccharide from probiotic strain Enterococcus faecium (BDU7) from Ngari.

"Ngari" is a traditional fermented fish of Manipur and considered for its therapeutic value in healing stomach ulcers. In the present study, an attempt was made to isolate and identify an efficient antioxidant probiotic isolate from Ngari. BDU7 with potent antioxidant property was isolated and characterized. The isolate was identified by 16S rRNA genotyping as Enterococcus faecium. E. faecium showed auto aggregation and hydrophobicity of 72.7 and 54.8% respectively. The extrapolysaccharide (EPS) was extracted from the culture free supernatant and assayed for its radical scavenging activity. The EPS showed significant 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (63.5%), superoxide (77.3%) and hydroxyl (38.4%) radical scavenging ability. The structural analysis of the extracted and purified EPS was performed by FTIR and NMR analysis. From the present study E. faecium BDU7 can be claimed as a promising and an efficient probiotic candidate. The present study evidenced that EPS from E. faecium BDU7 showed strong DPPH and superoxide radical scavenging ability in vitro. Considering its potency as a potential antioxidant the extracted EPS can find wide application in functional food and pharmaceutical formulations.