Polygonum viviparum L. inhibits the lipopolysaccharide‐induced inflammatory response in RAW264.7 macrophages through haem oxygenase‐1 induction and activation of the Nrf2 pathway |
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Authors: | Hui‐Wen Cheng Kock‐Chee Lee Khoot‐Peng Cheah Ming‐Long Chang Che‐Wei Lin Joe‐Sharg Li Wen‐Yu Yu E‐Tung Liu Chien‐Ming Hu |
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Affiliation: | 1. Department of Emergency Medicine, Taipei Medical University Hospital, Taipei, Taiwan;2. Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taiwan |
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Abstract: | BACKGROUND: Polygonum viviparum L. (PV) is a member of the family Polygonaceae and is widely distributed in high‐elevation areas. It is used as a folk remedy to treat inflammation‐related diseases. This study was focused on the anti‐inflammatory response of PV against lipopolysaccharide (LPS)‐induced inflammation in RAW264.7 macrophages. RESULTS: Treatment with PV did not cause cytotoxicity at 0–50 µg mL?1 in RAW264.7 macrophages, and the IC50 value was 270 µg mL?1. PV inhibited LPS‐stimulated nitric oxide (NO), prostaglandin (PG)E2, interleukin (IL)‐1β and tumour necrosis factor (TNF)‐α release and inducible NO synthase (iNOS) and cyclooxygenase (COX)‐2 protein expression. In addition, PV suppressed the LPS‐induced p65 expression of nuclear factor (NF)‐κB, which is associated with the inhibition of IκB‐α degradation. These results suggest that, among mechanisms of the anti‐inflammatory response, PV inhibits the production of NO and these cytokines by down‐regulating iNOS and COX‐2 gene expression. Furthermore, PV can induce haem oxygenase (HO)‐1 protein expression through nuclear factor E2‐related factor 2 (Nrf2) activation. A specific inhibitor of HO‐1, zinc(II) protoporphyrin IX, inhibited the suppression of iNOS and COX‐2 expression by PV. CONCLUSION: These results suggest that PV possesses anti‐inflammatory actions in macrophages and works through a novel mechanism involving Nrf2 actions and HO‐1. Thus PV could be considered for application as a potential therapeutic approach for inflammation‐associated disorders. © 2012 Society of Chemical Industry |
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Keywords: | Polygonum viviparum L lipopolysaccharide nuclear factor E2‐related factor 2 haem oxygenase‐1 RAW264.7 macrophages |
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