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Research Article
Aqueous Extract of
Oldenlandia diffusa Suppresses LPS-Induced iNOS,
COX-2 and TNF-α Expression in RAW 264.7 Cells via the
NF-κB Activity
RGPT Jayasooriya1, Chang-Hee
Kang1, Yung Hyun Choi2, Woo Shin
Ko3, Il-Whan Choi4 and 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:
E-mail:
immunkim@jejunu.ac.kr
Tel: +82-647543427Received:
11 November
2010
Revised accepted: 23 May 2011
Tropical
Journal of Pharmaceutical Research, Aug 2011;
10(4): 403-411
http://dx.doi.org/10.4314/tjpr.v10i4.5
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-α, NF-κB. |
