Anti-oxidant and anti-inflammatory effects of rice bran and green tea fermentation mixture on lipopolysaccharide-induced RAW 264.7 macrophages

Abstract

Purpose: To investigate the anti-inflammatory and anti-oxidant properties of an enzyme bath of Oryza sativa (rice bran) and Camellia sinensis O. Kuntz (green tea) fermented with Bacillus subtilis (OCB). Methods: The anti-oxidant effects of OCB were assessed by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay and flow cytometry. The anti-inflammatory effects of OCB were assessed by a nitric oxide (NO) assay. Enzyme-linked immunosorbent assay and real-time polymerase chain reaction were used to quantify expression of pro-inflammatory cytokines in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The major compounds of OCB were identified using high performance liquid chromatography (HPLC) analysis. Results: OCB had no cytotoxic effect on LPS-stimulated macrophages or peripheral blood mononuclear cells up to 1 mg/mL. OCB displayed anti-oxidant effects comparable to those of ascorbic acid and reduced reactive oxygen species (ROS) levels in target cells. OCB treatment of LPS-stimulated mavrophages decreased nitric oxide (NO), NO synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) and key pro-inflammatory cytokine expressions, suggesting that OCB acts as an anti-oxidant and anti-inflammatory agent by reducing ROS levels and inhibiting pro-inflammatory mediators. The main effector compounds in OCB were epicatechin gallate, cathechin, synigrin acid, epicathechin, epigallocatechin gallate, rutin, and isoquercetin, which are known anti-oxidants. Conclusion: OCB fermentation product may be used as synergistic adjuvant therapy for inflammatory diseases.