Antioxidant effects of live and heat-killed probiotic Lactobacillus plantarum Ln1 isolated from kimchi

The aim of this study was to evaluate the probiotic properties of Lactobacillus plantarum Ln1 isolated from kimchi and the antioxidant activities of live and heat-killed cells. L. plantarum KCTC 3108, which has been used as a commercial probiotic strain, was used as a control. L. plantarum strains (Ln1 and KCTC 3108) can survive under artificial gastric conditions (pH 2.5 in 0.3% pepsin for 3 h and 0.3% oxgall for 24 h), and adhere strongly to HT-29 cells. In addition, L. plantarum Ln1 did not produce carcinogenic β-glucuronidase, whereas it showed a higher β-galactosidase production of 3067.42 mU/mL. The antioxidant activity of L. plantarum Ln1 was assessed using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, β-carotene and linoleic acid inhibition, and reducing power assays. In all these methods, live L. plantarum Ln1 showed a higher antioxidant activity than the control strain. In heat-killed cells of L. plantarum Ln1, β-carotene bleaching inhibitory activity and reducing power was higher than DPPH and ABTS radical scavenging activity. These results suggested that live or heat-killed L. plantarum Ln1 isolated from kimchi might be useful as an antioxidant probiotic.