Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Aqueous Extract of Oldenlandia diffusa Suppresses LPS-Induced iNOS, COX-2 and TNF-α expression in RAW 264.7 Cells via the NF-kB Activity

RGPT Jayasooriya¹, Chang-Hee Kang¹, Yung Hyun Choi², Woo Shin Ko³, Il-Whan Choi⁴, Gi-Young Kim¹

¹Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju 690-756; ²Department of Biochemistry, College of Oriental Medicine, Dongeui University, Busan 614-054; ³Clinical Research Center of Oriental Medicine, Dongeui University, Busan 614-054; ⁴Department of Microbiology, College of Medicine, Inje University, Busan 614-735, Republic of Korea.

For correspondence:- Gi-Young Kim Email: immunkim@jejunu.ac.kr Tel:+82647543427

Received: 11 November 2010 Accepted: 23 May 2011 Published: 20 August 2011

Citation: Jayasooriya R, Kang C, Choi YH, Ko WS, Choi I, Kim G. Aqueous Extract of Oldenlandia diffusa Suppresses LPS-Induced iNOS, COX-2 and TNF-α expression in RAW 264.7 Cells via the NF-kB Activity. Trop J Pharm Res 2011; 10(4):403-411 doi: 10.4314/tjpr.v10i4.5

© 2011 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To elucidate the anti-inflammatory mechanisms of aqueous extract of Oldenlandia diffusa (AEOD) in LPS-stimulated RAW 264.7 cells.

Methods: We evaluated the mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and tumor necrosis factor (TNF)-α using RT-PCR and Western blot analyses. expressions of IκBα, phospho-IκBα and p65 were analyzed by Western blot analysis. The level of nitric oxide (NO) production was analyzed using Griess reaction. The release of prostaglandin E₂(PGE₂) and tumor necrosis factor (TNF)-α was determined using sandwich ELISA.

Results: AEOD significantly suppressed nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells without direct cytotoxicity. AEOD decreased the production of prostaglandin E₂ (PGE₂) and TNF-α in LPS-stimulated RAW 264.7 cells. LPS-induced mRNA and protein expression of iNOS, COX-2 and TNF-α were attenuated by treatment with AEOD. These data imply that AEOD tightly regulates the expression of these inflammatory mediators at the transcriptional level. Therefore, we determined the effects of AEOD on nuclear factor-κB (NF-κB) activity, which has been considered to be a potential transcriptional factor for regulating the expression of iNOS, COX-2 and TNF-α. As expected, AEOD suppressed the LPS-induced degradation and phosphorylation of IκBα and sustained the expression of p65 in the cytosol. Furthermore, AEOD substantially inhibited the LPS-induced DNA binding activity of NF-κB. These data show that AEOD may control NO, PGE₂ and TNF-α production via the suppression of NF-κB activity.

Conclusion: Our results suggest that AEOD has a high potential activity for regulating LPS-induced inflammation.

Keywords: Oldenlandia diffusa, NO, iNOS, COX-2, PGE2, TNF-^5;, NF-_4;B