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Sci Rep. 2017 Nov 27;7(1):16374. doi: 10.1038/s41598-017-12562-6.

Baicalein ameliorates TNBS-induced colitis by suppressing TLR4/MyD88 signaling cascade and NLRP3 inflammasome activation in mice.

Author information

1
Shanghai Key Laboratory of Formulated Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
2
Departments of Medicine and Genetics, Albert Einstein College of Medicine, Bronx, New York, 10461, USA.
3
Shanghai Key Laboratory of Formulated Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China. ztwang@shutcm.edu.cn.
4
Shanghai Key Laboratory of Formulated Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China. douwei123456@126.com.

Abstract

Baicalein (5,6,7-trihydroxyflavone), a predominant bioactive component isolated from the root of Scutellaria baicalensis Georgi, has established potent anti-inflammatory activity via multi-targeted mechanisms. However, little is known about the effect of baicalein on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, which shares pathology related to human Crohn's disease (CD). The present study demonstrated that baicalein alleviated the severity of TNBS-induced colitis in mice by decreasing the activity of myeloperoxidase (MPO) and the expression of pro-inflammatory mediators. The decline in the activation of nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) correlated with a decrease in the expression of mucosal toll-like receptor 4 (TLR4) and its adaptor myeloid differentiation factor 88 (MyD88). In vitro, baicalein down-regulated the TLR4/MyD88 signaling cascades (NF-κB and MAPKs) in lipopolysaccharide (LPS)-stimulated macrophages. At the upstream level, baicalein bound to the hydrophobic region of the myeloid differentiation protein-2 (MD-2) pocket and inhibited the formation of the LPS-induced MD-2/TLR4 complex. Furthermore, baicalein reduced NOD-like receptor 3 (NLRP3) inflammasome activation and downstream interleukin-1β expression in a dose-dependent manner. Our study provided evidence for the first time that baicalein attenuated TNBS-induced colitis, at least in part, via inhibition of TLR4/MyD88 signaling cascade as well as inactivation of NLRP3 inflammasome.

PMID:
29180692
PMCID:
PMC5703971
DOI:
10.1038/s41598-017-12562-6
[Indexed for MEDLINE]
Free PMC Article

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