Xiaoqing Xu1,2, Yu Qiao1, Qing Peng1, Bo Shi1, Vermont P Dia2. 1. Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China. 2. Department of Food Science, The University of Tennessee Institute of Agriculture, Knoxville, Tennessee, USA.
Abstract
BACKGROUND: Exopolysaccharides (EPS) from Lactobacillus spp. have been found to have biological activities. Our previous work demonstrated the antibiofilm activity of EPS from Lactobacillus casei NA-2 (L.casei NA-2) isolated from northeast Chinese sauerkraut (Suan Cai). The present study has focussed on the antioxidant and immunomodulatory activities of the EPS in vitro. METHODS: Antioxidant properties of the EPS were evaluated by the radical-scavenging activities in vitro. The immunomodulatory effects of EPS were assayed by measuring nitric oxide (NO), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and reactive oxygen species (ROS) in RAW 264.7 macrophages, and the mechanism was investigated through NF-κB and JNK. RESULT: EPS contains 88% total sugar, with the molecular weights (Mw) of 1.3 × 106 Da, 6.4 × 105 Da, 2.0 × 105 Da, and 1.4 × 104 Da. EPS showed antioxidant activity by scavenging hydroxyl radicals (42% at 1.2 mg/mL), superoxide radicals (76% at 100 µg/mL), and DPPH (80% at 10 mg/mL); and did not affect the proliferation of unstimulated or lipopolysaccharide (LPS)-induced RAW 264.7 cells at the concentrations ranging from 31.25 to 500 µg/mL. Results showed EPS promoted the production of ROS and TNF-α involved in NF-κB p65 and JNK signaling pathways in unstimulated RAW 264.7 cells. On the other hand, the levels of NO and iNOS were reduced after EPS treatment in LPS-induced RAW 264.7 cells. CONCLUSION: Our results showed the protective effect against oxidative damage and potential immunomodulatory and anti-inflammatory properties of EPS from Lactobacillus casei NA-2.
BACKGROUND: Exopolysaccharides (EPS) from Lactobacillus spp. have been found to have biological activities. Our previous work demonstrated the antibiofilm activity of EPS from Lactobacillus casei NA-2 (L.casei NA-2) isolated from northeast Chinese sauerkraut (Suan Cai). The present study has focussed on the antioxidant and immunomodulatory activities of the EPS in vitro. METHODS: Antioxidant properties of the EPS were evaluated by the radical-scavenging activities in vitro. The immunomodulatory effects of EPS were assayed by measuring nitric oxide (NO), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and reactive oxygen species (ROS) in RAW 264.7 macrophages, and the mechanism was investigated through NF-κB and JNK. RESULT: EPS contains 88% total sugar, with the molecular weights (Mw) of 1.3 × 106 Da, 6.4 × 105 Da, 2.0 × 105 Da, and 1.4 × 104 Da. EPS showed antioxidant activity by scavenging hydroxyl radicals (42% at 1.2 mg/mL), superoxide radicals (76% at 100 µg/mL), and DPPH (80% at 10 mg/mL); and did not affect the proliferation of unstimulated or lipopolysaccharide (LPS)-induced RAW 264.7 cells at the concentrations ranging from 31.25 to 500 µg/mL. Results showed EPS promoted the production of ROS and TNF-α involved in NF-κB p65 and JNK signaling pathways in unstimulated RAW 264.7 cells. On the other hand, the levels of NO and iNOS were reduced after EPS treatment in LPS-induced RAW 264.7 cells. CONCLUSION: Our results showed the protective effect against oxidative damage and potential immunomodulatory and anti-inflammatory properties of EPS from Lactobacillus casei NA-2.
Entities:
Keywords:
Exopolysaccharide; Lactobacillus casei NA-2; RAW 264.7 macrophages; cytokines; radical-scavenging; reactive oxygen species (ROS)