Anti-Inflammatory Activity of Aucubin by Inhibition of Tumor Necrosis Factor-α Production in RAW 264.7 Cells

Abstract

To elucidate a possible mechanism for the anti-inflammatory action of iridoid glycosides, the effects of both aucubin (AU) and its hydrolyzed product (H-AU) by β-glucosidase treatment were studied on the production of TNF-α in RAW 264.7 cells. H-AU suppressed the production of both mRNA for TNF-α and subsequent TNF-α protein in the culture, but AU did not. The production of TNF-α protein was inhibited in a dose-dependent manner with an IC₅₀ of 9.2 μM. In addition, treatment with H-AU blocked both the I-κBα degradation and the translocation of NF-κB from the cytosol fraction to the nuclear fraction (55 % inhibition) in the culture. However, treatment with H-AU did not affect the intracellular level of cAMP formed by forskolin treatment in human monocytes U937 culture, implying that there is no influence on the cAMP level in other cell systems. The present study indicates a possible justification for those medicinal plants containing iridoid glycoside that have been used for the treatment of inflammation.

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