Probiotic characteristics of Lactobacillus brevis B13-2 isolated from kimchi and investigation of antioxidant and immune-modulating abilities of its heat-killed cells

The aim of this study was to evaluate the probiotic, antioxidant, and immune-modulating properties of Lactobacillus brevis B13-2, isolated from kimchi. L. brevis B13-2 exhibited tolerance against artificial gastric acid and bile salts, and it adhered to HT-29 cells. This strain did not produce beta-glucuronidase, which is carcinogenic in humans. These results indicate that this strain could serve as a beneficial probiotic in the human intestine. Viable cells showed higher DPPH radical scavenging activity, whereas heat-killed cells displayed higher ABTS radical scavenging activity. Heat-killed cells also showed high activity in a beta-carotene assay. Antioxidant activity was consistently higher in L. brevis B13-2 than in L. rhamnosus GG. Furthermore, both viable and heat-killed L. brevis B13-2 cells induced the expression of several cytokines (TNF-alpha, IL-1 beta, and IL-6) and iNOS by activation of RAW 264.7 murine macrophages. These results suggest that L. brevis B13-2 has probiotic characteristics; both viable and heat-killed cells showed high antioxidant activity and immune-modulating ability. Therefore, applications for this strain could include functional food processing and pharmaceutical therapeutic approaches for immunocompromised people.