Characterization of an exopolysaccharide with potential health-benefit properties from a probiotic Lactobacillus plantarum RJF4

Exopolysaccharides (EPS) are macromolecules composed of sugar and sugar derivatives and the function and applications mainly depend on their monosaccharide composition, molecular weight and branching. EPS from the food-grade Lactic acid bacteria (LAB) serves as natural alternatives to commercial additives. One heteropoysaccharide produced by a recently isolated (from rotten jack fruit) Lactobacillus plantarum RJF4 was extracted and purified. HPLC analysis and FTIR spectroscopy revealed that it is composed of glucose and mannose. The EPS was tolerant to temperature up to 225 °C. In vitro assays showed that the EPS possesses total antioxidant capacity (32%), DPPH radical scavenging ability (23.63%) and reduction potential (50% compared to the control ascorbic acid). It also displayed cholesterol lowering property (42.24%) and α-amylase inhibition (40%), which is an in vitro assay for evaluating anti diabetic property. The cytotoxicity studies (MTT assay and Alamar Blue assay) revealed cancer cell specific anti proliferative effects of EPS. It showed to be toxic to MiaPaCa2-pancreatic cancer cell line in dose dependent manner and remained nontoxic to normal cell line (L6 and L929 fibroblast cells).