Isolation for the Antioxidant Activity of Metabolites from Lactobacillus sp. A-2

In the study, the preparation of metabolites by fermentation of Lactobacillus sp. A-2 in the desalted whey protein powder medium, separation of Lactobacillus sp. A-2 metabolites using a Diethylaminoethyl-Sephacel column (2.6 × 50 cm) and a dextran gel (Sephadex-G15) column (1.6 × 100 cm). The antioxidant activity of fractions was evaluated by the 2,2-biazo-bis(3-ethyl-benzothiazole-6-sulphonic acid) diammonium salt (ABTS) method and the oxygen radical absorbance capacity (ORAC) method. Lactobacillus sp. A-2 metabolites were isolated and purified to obtain two antioxidant active fractions DF1-1 and DEF1-1, with IC50 values of 1.21 mg/mL and 1.98 mg/mL for ABTS cation free radical scavenging activity and relative ORAC values of 257.8 µmol Trolox/g and 267.3 µmol Trolox/g, respectively. Meanwhile, the SDS-PAGE gel electrophoresis was used to analyze the molecular mass distribution of peptides in the components of DF1, DF1-1, DEF1 and DEF1-1, as a result, the components DEF1-1 contained more peptides.