Biomedical subjects

Kyong Up Baik

Publications and source records attributed to Kyong Up Baik.

4 recordsLinked to original sources

PubMed2004

Differential effect of phosphodiesterase IV inhibitor RP73401 on various inflammatory and immune responses relevent to rheumatoid arthritis.

Phosphodiesterase (PDE) IV inhibitors have been reported to possess potent anti-inflammatory activities through enhancement of cAMP. In this study, the immunopharmacological effect of PDE IV inhibitor (RP73401) was further carefully evaluated. RP73401 strongly blocked the production of tumor necrosis factor (TNF)-alpha from lipopolysaccharide (LPS)-stimulated murine macrophages (RAW264.7) and human peripheral blood mononuclear cells (PBMC) and LPS-primed mice. RP73401 did not relieve joint inflammation in adjuvant-arthritis (RA) model, whereas the compound attenuated arachidonic acid-induced inflammation. RP73401 displayed weak or no modulatory effects on the activation of macrophage and lymphocytes (assessed by proliferation, nitric oxide (NO) release and cell-cell adhesion, TNF-alpha production upon phorbol 12-myristate 13-acetate (PMA) treatment), and fluorescein-isothiocynate (FITC)-induced ear oedema. Collectively, these data suggest that PDE IV inhibitor RP73401 may differentially modulate various immune responses and these may explain its inability to inhibit adjuvant-induced joint inflammation or FITC-induced ear oedema.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2004

Effects of dialkoxylphenyl compounds with oxime group on macrophage function and the proliferation of lymphocytes.

Dialkoxyphenyl compounds have been reported to possess anti-inflammatory activity through inhibition of phosphodieseterase (PDE) type IV. In this study, a series of derivatives of dialkoxyphenyl compounds with an oxime group, which is generally known to be one of the biologically active functional groups, were prepared and evaluated for their ability to inhibit the production of inflammatory mediators in activated macrophages and the proliferation of lymphocytes. The structure-activity relationship (SAR) study with 12 compounds on tumour necrosis factor (TNF)-alpha inhibition, analysed by the oxime geometry and different size of spacers between the oxime and phenyl group, indicated that there might be at least three possible hydrogen bonding sites in the inhibitor binding pocket of PDE IV. Of them, compound 6 clearly displayed the highest inhibitory effect on in-vitro TNF-alpha production from lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 6 also suppressed in-vivo TNF-alpha release from LPS-primed mice, a level comparable with that of the standard PDE IV inhibitor, rolipram. In addition, oxime compounds also significantly inhibited both nitric oxide production from activated RAW264.7 cells and T lymphocyte proliferation elicited by concanavalin A but not IL-2. The data suggest that the oxime group may act as a functional group, capable of interacting with the inhibitor-binding pocket of target PDE IV. Therefore, it is conceivable that compound 6 may have the potential either to be developed as a new anti-inflammatory drug or to be used to develop more potent analogues.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2002

Ginsenosides from Panax ginseng differentially regulate lymphocyte proliferation.

We have examined the immunosuppressive effects of representative ginsenosides (Rb1, Rb2, Re and Rg1) from Panax ginseng C. A. Meyer on CD4+ and CD8+ lymphocyte proliferation. Ginsenosides differentially modulated lymphocyte proliferation induced by concanavalin A (Con A), lipopolysaccharide (LPS), phytohemaglutinin (PHA) and interleukin-2 (IL-2). Thus, Rb1 and Re significantly enhanced Con A-induced lymphocyte proliferation, whereas Rg1 did not affect the proliferation. Interestingly, however, Rb2 strongly blocked Con A, LPS and PHA-induced lymphocyte proliferation with the IC50 values of 21.8, 29.0 and 24.0 microM, respectively. Moreover, Rb2 inhibited Con A-stimulated IL-2 production with an IC 50 of 13.3 microM. In the IL-2-stimulated CD8+ T cell (CTLL-2) proliferation assay, Re and Rg1 showed strong suppressive effects with IC50 values of 57.5 and 64.7 microM, respectively. In contrast, neither Rb1 nor Rb2 did inhibit CTLL-2 cell proliferation at tested concentrations. These results suggest that ginsenosides from P. ginseng may modulate lymphocyte proliferation in a different manner.

Animals↗

PubMed2002

Synthesis and SAR studies for the inhibition of TNF-alpha production. Part 2. 2-[3-(Cyclopentyloxy)-4-methoxyphenyl]-substituted-1-isoindolinone derivatives.

This study describes the synthesis and in vitro evaluation of 2-[3-(cyclopentyloxy)-4-methoxyphenyl]-1-isoindolinone derivatives substituted on benzene moiety of isoindoline ring for the inhibition of TNF-alpha production. From this study, we have found the 6-C position on isoindolinone ring is an optimal derivatization site. Among the compounds synthesized, 6-amino-2-[3-(cyclopentyloxy)-4-methoxyphenyl]-1-isoindolinone (6) was the most potent in inhibitory activity of TNF-alpha production in LPS-stimulated RAW264.7 cells.

Animals↗