title: Oryza sativa(Rice) Hull Extract Inhibits Lipopolysaccharide-Induced Inflammatory Response in RAW264.7 Macrophages by Suppressing Extracellular Signal-regulated Kinase, c-Jun N-terminal Kinase, and Nuclear Factor-κB Activation.
abstract: BACKGROUND
  Rice (Oryza sativa) is a major cereal crop in many Asian countries and an important staple food source. Rice hulls have been reported to possess antioxidant activities.
  
  
  METHODS
  In this study, we evaluated the antiinflammatory effects of rice hull extract and associated signal transduction mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.
  
  
  RESULTS
  We found that rice hull extract inhibited nitric oxide (NO) and prostaglandin E2by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively. The release of interleukin-1β and tumor necrosis factor-α was also reduced in a dose-dependent manner. Furthermore, rice hull extract attenuated the activation of nuclear factor-kappa B (NF-κB), as well as the phosphorylation of mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), in LPS-stimulated RAW264.7 cells.
  
  
  CONCLUSIONS
  This suggests that rice hull extract decreases the production of inflammatory mediators by downregulating ERK and JNK and the NF-κB signal pathway in RAW 264.7 cells.
  
  
  CONCLUSIONS
  Rice hull extract inhibits the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages.Rice hull extract inhibited nitric oxide and prostaglandin E2by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively.Rice hull extract exerted anti-inflammatory effect through inhibition of nuclear factor-kappa B, extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways.Rice hull extract may provide a potential therapeutic approach for inflammatory diseases.Abbreviations used:COX-2: cyclooxygenase-2, ERK: extracellular signal-regulated kinase, IκB: inhibitory kappa B, IL-1β: interleukin-1β, iNOS: inducible NO synthase, JNK: c-Jun N-terminal kinase, LPS: lipopolysaccharide, MAPKs: mitogen-activated protein kinases, NF-κB: nuclear factor-κB, NO: nitric oxide, PGE2: prostaglandin E2, RHE: rice hull extract, ROS: reactive oxygen species, TNF-α: tumor necrosis factor-α.
authors.affiliation: Research Group of Nutraceuticals for Metabolic Syndrome, Korea Food Research Institute, Gyeonggi, Republic of Korea; Division of Food Biotechnology, University of Science and Technology, Daejeon, Republic of Korea.
authors.forename: Sang Keun
authors.initials: SK
authors.lastname: Ha
authors.affiliation: Research Group of Nutraceuticals for Metabolic Syndrome, Korea Food Research Institute, Gyeonggi, Republic of Korea.
authors.forename: Jeehye
authors.initials: J
authors.lastname: Sung
authors.affiliation: Research Group of Nutraceuticals for Metabolic Syndrome, Korea Food Research Institute, Gyeonggi, Republic of Korea.
authors.forename: Inwook
authors.initials: I
authors.lastname: Choi
authors.affiliation: Research Group of Nutraceuticals for Metabolic Syndrome, Korea Food Research Institute, Gyeonggi, Republic of Korea.
authors.forename: Yoonsook
authors.initials: Y
authors.lastname: Kim
keywords: COX-2; Inflammation; Rice hull; iNOS