Background: The natural antioxidants from biological resources have gained much attention. There are reports of some strains of Lactobacillus that may be a good natural source for antioxidants, thereby helping the human body from oxidative damages.
Objective: To investigate the antioxidant activities and probiotic properties of strains isolated from healthy infants.
Materials and Methods: Probiotic isolates were selected for in vitro antioxidant activities of probiotics using hydroxyl and DPPH radical scavenging, and intracellular free radical. The selected probiotic was identified by 16S rRNA gene sequencing and determined for probiotic properties including resistance to simulated gastrointestinal conditions, adhesion property, hemolysis activity, antimicrobial and antibiotic activity.
Results: Among probiotic isolates, viable cells, cell free supernatant and intracellular cell free extract of MSMC37-3 exhibited antioxidant capacities. MSMC37-3 isolate was identified as Lactobacillus paracasei on basis of 16S rRNA gene sequencing. L. paracasei MSMC37-3 showed more than 95% survival rate in simulated gastrointestinal conditions, adherent to intestinal cells and did not show hemolytic activity. L. paracasei MSMC37-3 exhibited antimicrobial activity against 9 indicator bacteria. L. paracasei MSMC37-3 was susceptible to eight antibiotics.
Conclusion: These results indicated that L. paracasei MSMC37-3 is a potential probiotic strain for application in the development of healthy products.

Keywords: Probiotics; Lactobacillus; Free radical; Antioxidant; Oxidative stress; Probiotic properties