Planta Med 2003; 69(8): 687-691
DOI: 10.1055/s-2003-42779
Original Paper
Pharmacology
© Georg Thieme Verlag Stuttgart · New York

Involvement of Nuclear Factor-κB in the Inhibition of Interleukin-12 Production from Mouse Macrophages by Baicalein, a Flavonoid in Scutellaria baicalensis

Bok Yun Kang1 , 3 , Su Wol Chung1 , Seung Hyun Kim1 , Daeho Cho2 , Tae Sung Kim1
  • 1College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Kwangju, Republic of Korea
  • 2Department of Life Science, Sookmyung Women’s University, Seoul, Republic of Korea
  • 3Present address: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
Further Information

Publication History

Received: January 2, 2003

Accepted: March 11, 2003

Publication Date:
06 October 2003 (online)

Abstract

Pharmacological inhibition of interleukin-12 (IL-12) production may be a therapeutic strategy for preventing development and progression of disease in experimental models of autoimmunity. In this study we investigated the effects of baicalein, a flavonoid present in the root of Scutellaria baicalensis, on the production of IL-12 from mouse macrophages stimulated with lipopolysaccharide (LPS). Baicalein potently inhibited the LPS-induced IL-12 production from both primary macrophages and RAW264.7 monocytic cell-line in a dose-dependent manner (the IC50 values were 43.7 and 17.4 μM, respectively). The effect of baicalein on IL-12 gene promoter activation was analyzed by transfecting RAW264.7 cells with IL-12 gene promoter/luciferase constructs. The repressive effect mapped to a region in the IL-12 gene promoter containing a binding site for NF-κB. Furthermore, activation of macrophages by LPS resulted in markedly enhanced binding activity to the NF-κB site, which significantly decreased upon addition of baicalein, indicating that baicalein inhibited IL-12 production in LPS-activated macrophages via inhibition of NF-κB binding activity.

Abbreviations

IL:interleukin

LPS:lipopolysaccharide

NK-κB:nuclear factor-κB

Th1:T helper type 1

ELISA:enzyme-linked immunosorbent assay

PCR:polymerase chain reaction

References

Tae Sung Kim, Ph. D.

College of Pharmacy

Chonnam National University

Kwangju 500-757

Republic of Korea

Fax: +82-62-530-2911

Email: taekim@chonnam.ac.kr