title: 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.
abstract: 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.
authors.affiliation: Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Republic of Korea.
authors.forename: Hee-Sung
authors.initials: HS
authors.lastname: Chae
authors.forename: Ok-Hwa
authors.initials: OH
authors.lastname: Kang
authors.forename: Jang-Gi
authors.initials: JG
authors.lastname: Choi
authors.forename: You-Chang
authors.initials: YC
authors.lastname: Oh
authors.forename: Young-Seob
authors.initials: YS
authors.lastname: Lee
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Jang
authors.forename: Jong Hak
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyun
authors.initials: H
authors.lastname: Park
authors.forename: Kyu Yong
authors.initials: KY
authors.lastname: Jung
authors.forename: Dong Hwan
authors.initials: DH
authors.lastname: Sohn
authors.forename: Dong-Yeul
authors.initials: DY
authors.lastname: Kwon