Prostaglandins and nitric oxide (NO) are among the numerous substances released by activated microglial cells, the brain resident macrophages, and they mediate several important microglial functions. We have previously shown that cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS), the two key
Suppression of inducible nitric oxide synthase and cyclooxygenase-2 in downregulating nuclear factor-kappa B pathway by Garcinol
✍ Scribed by Chiung-Ho Liao; Shengmin Sang; Yu-Chih Liang; Chi-Tang Ho; Jen-Kun Lin
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 353 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0899-1987
- DOI
- 10.1002/mc.20050
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Garcinol is a polyisoprenylated benzophenone derivative of Garcinia indica fruit rind and other species. Recent studies have demonstrated that garcinol exhibited antioxidative effects in vitro. In this study, we found that garcinol inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) in lipopolysaccharide (LPS)‐activated macrophages. Western blot analyzes and gel‐shift assays revealed that garcinol strongly blocks the activation of eukaryotic transcription factor nuclear factor‐kappa B (NF‐κB)‐induced by LPS. Moreover, transient transfection experiments showed that garcinol inhibited the NF‐κB‐dependent transcriptional activity. Based on these data, we demonstrated that inhibition of LPS‐induced NF‐κB activation occurred through suppressing the phosphorylation of IκBα and p38 mitogen‐activated kinase (MAPK). Garcinol also lowers the LPS‐induced increase of intracellular reactive oxygen species (ROS), which contributes to the activation of NF‐κB. The NF‐κB signaling pathway leads to inflammatory reaction and our results suggest that garcinol suppresses the expression of iNOS in this pathway. © 2004 Wiley‐Liss, Inc.
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