5-hydroxytryptophan acts on the mitogen-activated protein kinase extracellular-signal regulated protein kinase pathway to modulate cyclooxygenase-2 and inducible nitric oxide synthase expression in RAW 264.7 cells.
In this study, we evaluated the effect of 5-hydroxytryptophan on anti-inflammatory and analgesic activity in RAW 264.7 cells. Cells were treated with different concentrations of 5-hydroxytryptophan for either 1 h or for 24 h. The anti-inflammatory effect was then analyzed by enzyme-linked immunosorbent assay (ELISA), Western blotting and reverse transcription polymerase chain reaction (RT-PCR). In addition, the analgesic activity was evaluated by measuring the acetic acid-induced writhing response. We found that 5-hydroxytryptophan significantly reduced the acetic acid-induced writhing response. Moreover we evaluated the effects of 5-hydroxytryptophan on the release of several inflammatory mediators including nitric oxide (NO) and interleukin-6 (IL-6). Our results demonstrated that 5-hydroxytryptophan inhibited the lipopolysaccharide (LPS)-induced expression of NO and IL-6. Furthermore, we found that 5-hydroxytryptophan played a role in LPS induced inducible nitric oxide synthase (iNOS), cyclo oxygenase-2 (COX-2) and extracellular-signal regulated protein kinase (ERK) activation. Taken together, these results indicate that 5-hydroxytryptophan has the potential for use in the treatment of inflammatory disease and as an analgesic.
Chae
Hee-Sung
HS
Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Republic of Korea.
Kang
Ok-Hwa
OH
Choi
Jang-Gi
JG
Oh
You-Chang
YC
Lee
Young-Seob
YS
Jang
Hye-Jin
HJ
Kim
Jong Hak
JH
Park
Hyun
H
Jung
Kyu Yong
KY
Sohn
Dong Hwan
DH
Kwon
Dong-Yeul
DY