Anti-Inflammatory Effects of Flavonoids: Genistein, Kaempferol, Quercetin, and Daidzein Inhibit STAT-1 and NF-κB Activations, Whereas Flavone, Isorhamnetin, Naringenin, and Pelargonidin Inhibit only NF-κB Activation along with Their Inhibitory Effect on iNOS Expression and NO Production in Activated Macrophages
In inflammation, bacterial products and proinflammatory cytokines induce the formation of large amounts of nitric oxide (NO) by inducible nitric oxide synthase (iNOS), and compounds that...
Main Authors: | , , , , |
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Format: | Article |
Language: | English |
Published: |
Hindawi Limited
2007-01-01
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Series: | Mediators of Inflammation |
Online Access: | http://dx.doi.org/10.1155/2007/45673 |
Summary: | In inflammation, bacterial products and proinflammatory
cytokines induce the formation of large amounts of nitric oxide (NO)
by inducible nitric oxide synthase (iNOS), and compounds that
inhibit NO production have anti-inflammatory effects.
In the present study, we systematically investigated the effects of 36 naturally occurring flavonoids and
related compounds on NO production in macrophages exposed to an inflammatory stimulus
(lipopolysaccharide, LPS), and evaluated the mechanisms of action of the effective compounds.
Flavone, the isoflavones daidzein and genistein, the flavonols isorhamnetin, kaempferol and quercetin,
the flavanone naringenin, and the anthocyanin pelargonidin inhibited iNOS protein and mRNA
expression and also NO production in a dose-dependent manner. All eight active compounds
inhibited the activation of nuclear factor-κB (NF-κB), which is a significant transcription factor for iNOS. Genistein, kaempferol, quercetin,
and daidzein also inhibited the activation of the signal transducer and activator of transcription
1 (STAT-1), another important transcription factor for iNOS.
The present study characterises the effects and mechanisms of naturally occurring phenolic
compounds on iNOS expression and NO production in activated macrophages. The results partially
explain the pharmacological efficacy of flavonoids as anti-inflammatory compounds. |
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ISSN: | 0962-9351 1466-1861 |