Planta Med 2017; 83(06): 527-533
DOI: 10.1055/s-0042-119074
Biological and Pharmacological Activity
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Tangeretin Inhibits IL-12 Expression and NF-κB Activation in Dendritic Cells and Attenuates Colitis in Mice

Su-Hyeon Eun
1   Department of Life and Nanopharmaceutical Sciences and Department of Pharmacy, Kyung Hee University, Seoul, Korea
,
Je-Te Woo
2   Research Institute for Biological Functions, Chubu University, Aichi, Japan
,
Dong-Hyun Kim
1   Department of Life and Nanopharmaceutical Sciences and Department of Pharmacy, Kyung Hee University, Seoul, Korea
› Institutsangaben
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Publikationsverlauf

received 26. Juni 2016
revised 30. September 2016

accepted 10. Oktober 2016

Publikationsdatum:
02. November 2016 (online)

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Abstract

In the preliminary study, tangeretin (5,6,7,8,4′-pentamethoxy flavone), a major constituent of the pericarp of Citrus sp., inhibited TNF-α, IL-12, and IL-23 expression and nuclear factor kappa-B activation in lipopolysaccharide-stimulated dendritic cells; however, it did not affect IL-10 expression. Furthermore, tangeretin (5, 10, and 20 µM) suppressed the activation and translocation of nuclear factor kappa-B (p65) into the nuclei in vitro by inhibiting the binding of lipopolysaccharide on dendritic cells. Oral administration of tangeretin (10 and 20 mg/kg) suppressed the inflammatory responses, such as nuclear factor kappa-B and mitogen-activated protein kinase activation and myeloperoxidase activity, in the colon of mice with 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Tangeretin increased 2,4,6-trinitrobenzene sulfonic acid-suppressed expression of tight junction proteins occludin, claudin-1, and ZO-1. Tangeretin also inhibited 2,4,6-trinitrobenzene sulfonic acid-induced differentiation of Th1 and Th17 cells as well as the expression of T-bet, RORγt, interferon-γ, IL-12, IL-17, and TNF-α. However, tangeretin increased 2,4,6-trinitrobenzene sulfonic acid-suppressed differentiation of regulatory T cells as well as the expression of Foxp3 and IL-10. These results suggest that oral administration of tangeretin may attenuate colitis by suppressing IL-12 and TNF-α expression and nuclear factor kappa-B activation through the inhibition of lipopolysaccharide binding on immune cells such as dendritic cells.

Supporting Information

Methods for flow cytometry and confocal microscopy, flow cytometry of Th1, Th17, and Tregs in the lamina propria of mouse colons, histological examination, ELISA, and immunoblotting are available as Supporting Information.