Roots ofErigeron annuusAttenuate Acute Inflammation as Mediated with the Inhibition of NF-κB-Associated Nitric Oxide and Prostaglandin E2production

Mi Jeong Jo,Sang Chan Kim,Young Woo Kim,Jong Rok Lee,Il Je Cho

doi:10.1155/2013/297427

Mi Jeong Jo, Sang Chan Kim + Show 3 more

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https://doi.org/10.1155/2013/297427

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Abstract

Erigeron annuus is a naturalized plant belonging to Compositae (asteraceae) family, which is called the annual fleabane, and commonly found at meadows and roadside. This study investigated the anti-inflammatory effects of the extract of E. annuus roots (EER), as assessed by the paw edema formation and histological analysis in rat, and the productions of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines in Raw264.7 murine macrophages. Carrageenan treatment promoted infiltration of inflammatory cells and caused swelling in the hind paw. Oral administrations of EER (0.3 g/kg and 1 g/kg) attenuated acute inflammation similar to the result using dexamethasone (1 mg/kg). Treatment of macrophages with lipopolysaccharide (LPS) simulated inflammatory condition: LPS significantly increased the productions of NO, PGE2, and proinflammatory cytokines. EER suppressed activation of macrophages, preventing the induction of iNOS and COX-2 protein expressions. LPS treatment induced phosphorylation of I-κBα and increased the level of nuclear NF-κB protein, both of which were suppressed by concomitant treatment of EER. In conclusion, EER ameliorated acute inflammation in rats, and the induction of NO, PGE2, and proinflammatory cytokines in Raw264.7 cells. EER's effects may be associated with its inhibition of NF-κB activation, suggesting its effect on inflammatory diseases.

Highlights

Inflammation of human body is one of the most important biological responses to harmful stimuli during the host defense mechanism
We investigated the potential effect of the extract of E. annuus roots (EERs) on acute inflammation induced by carrageenan injection in rats
This study identified EER as an active component having an ability of the inhibitory effects on LPS-stimulated Inducible nitric oxide synthase LPS (iNOS) and Cyclooxygenase EER (COX)-2 expressions as well as TNF-α and IL-1β productions in RAW264.7 macrophages

Summary

Introduction

Inflammation of human body is one of the most important biological responses to harmful stimuli (e.g., pathogens or damaged cells) during the host defense mechanism. Macrophage is one of the most important phagocytic cells and plays a crucial role in the process of inflammation by producing proinflammatory mediators. INOS is a key regulator for inducing a large quantity of NO during inflammation and is indicated in many cell types such as macrophage, endothelial, and epithelial cells [13, 14]. PGE2 is another important inflammatory mediator which is produced from arachidonic acid through the catalytic reaction by COX-2 [15, 16]. It has been shown that iNOS and COX-2 are transcriptionally activated by NFκB, one of the most important transcription factors regulating the immune responses, cell adhesion, and survival [17,18,19]

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