Inhibitory effects of p-cresol and p-hydroxy anisole dimers on expression of the cyclooxygenase-2 gene and lipopolysaccharide-stimulated activation of nuclear factor-κB in RAW264.7 cells.
BACKGROUND/AIM
Phenolic compounds, particularly dihydroxybiphenyl-related compounds, possess efficient anti-oxidative and anti-inflammatory activity. We investigated the anti-inflammatory activity of 2,2'-dihydroxy-5,5'-dimethylbiphenol (p-cresol dimer), 2,2'-dihydroxy-5,5'-dimethoxybiphenol (pHA dimer), p-cresol, p-hydroxyanisole (pHA) and 2-t-butyl-4-hydroxyanisole (BHA).


MATERIALS AND METHODS
The cytotoxicity of the investigated compounds against RAW264.7 cells was determined using a cell counting kit (CCK-8). Their inhibitory effects on cyclooxygenase-2 (Cox2) mRNA expression stimulated by lipopolysaccharide (LPS) were determined using northern blot analysis, and their inhibition of LPS-stimulated nuclear factor-kappa B (Nf-κb) activation was evaluated using enzyme-linked immunosorbent assay-like microwell colorimetric transcription factor activity assay. The molecular orbital energy was calculated on the basis of density function theory BLYP/6-31G*.


RESULTS
The cytotoxicity of the compounds declined in the order pHA dimer > p-cresol dimer > BHA > p-cresol > pHA. The inhibitory effect on Cox2 expression and Nf-κb activation was enhanced by p-cresol dimer and pHA dimer, particularly the former, suggesting potent anti-inflammatory activity, whereas p-cresol and pHA showed weak activity, and BHA no activity. Both p-cresol dimer and pHA dimer were highly electronegative, as determined by quantum chemical calculations.


CONCLUSION
Dimerization of p-cresol and pHA enhances their anti-inflammatory activity. p-Cresol dimer and pHA dimer, particularly the former, are potent anti-inflammatory agents.
['Murakami|Yukio|Y|', 'Kawata|Akifumi|A|', 'Ito|Shigeru|S|', 'Katayama|Tadashi|T|', 'Fujisawa|Seiichiro|S|']
D000818:Animals D000840:Anisoles D002460:Cell Line D003408:Cresols D051546:Cyclooxygenase 2 D019281:Dimerization D004305:Dose-Response Relationship, Drug D004789:Enzyme Activation D005786:Gene Expression Regulation D008070:Lipopolysaccharides D008264:Macrophages D051379:Mice D016328:NF-kappa B D012333:RNA, Messenger
p-hydroxy anisole dimer RAW264.7 cells p-Cresol dimer cytotoxicity Cox2 Nf-κb antioxidative activity quantum molecular properties