The Aqueous Extract of Radio-Resistant Deinococcus actinosclerus BM2T Suppresses Lipopolysaccharide-Mediated Inflammation in RAW264.7 Cells

Deinococcus actinosclerus BM2(T) (GenBank: KT448814) is a radio-resistant bacterium that is newly isolated from the soil of a rocky hillside in Seoul. As an extremophile, D. actinosclerus BM2(T) may possess anti-inflammatory properties that may be beneficial to human health. In this study, we evaluated the anti-inflammatory effects of BM2U, an aqueous extract of D. actinosclerus BM2(T), on lipopolysaccharide (LPS)-mediated inflammatory responses in RAW264.7 macrophage cells. BM2U showed antioxidant capacity, as determined by the DPPH radical scavenging (IC(50) = 349.3 μg/ml) and ORAC (IC(50) = 50.24 μg/ml) assays. At 20 μg/ml, BM2U induced a significant increase in heme oxygenase-1 (HO-1) expression (p < 0.05). BM2U treatment (0.2-20 μg/ml) significantly suppressed LPS-induced increase in the mRNA expression of proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 (p < 0.05). BM2U treatment also suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which are involved in the production of inflammatory mediators. BM2U treatment also inhibited the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs): JNK, ERK, and p-38 (p < 0.05). Collectively, BM2U exhibited anti-inflammatory potential that can be exploited in attenuating inflammatory responses.