aurapten and Edema

This study aimed to evaluate the anti-inflammatory effect of Auraptene (AUR) and Umbelliprenin (UMB) in a rat model of rheumatoid arthritis (RA) induced by using complete Freund's adjuvant (CFA). Paw swelling of adjuvant arthritis rats measured at various times after CFA injection. Over 15 days of RA induction, mediator/cytokine-mediated processes involved in managing the regulation and resolving RA's inflammation were also quantified with ELISA. Histopathological changes were also assessed under a microscope 15 days after the CFA injection. AUR at all doses and UMB administration only at a 16 mM /kg administration dose significantly reduced CFA-induced paw edema level compared to the control group. UMB (64 and 32 mM) and AUR (64, 32, and 16 mM) could reduce the PGE2 (p < .0001-.01) and NO (p < .0001-.05) levels in the treatment groups compared to the negative control group. However, these compounds showed no significant effect on the TNF-α, IFN-γ, TGF-β, IL-4, and IL-10 levels than the control group (p > .05). Unlike indomethacin and prednisolone, treatment of rats with AUR (16, 32, and 64 mM/kg) and UMB (16 and 32 mM/kg) reduced the level of IL-2 (p < .0001). In all treatment groups, the serum level of IL-17 was significantly reduced compared to the CFA group (p < .001-0.05). We suggested AUR and UMB could diminish inflammation by reducing the serum level of IL-17 and could be considered a proper alternative in the treatment of IL-17 related inflammatory diseases such as rheumatoid arthritis. Given that AUR and UMB apply their anti-inflammatory effects by changing distinct cytokine release/inhibition patterns, their potential application in diverse inflammatory diseases seems different.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Arthritis; Arthritis, Experimental; Arthritis, Rheumatoid; Coumarins; Cytokines; Edema; Freund's Adjuvant; Inflammation; Male; Protective Agents; Rats; Rats, Wistar; Umbelliferones

Auraptene (AUR), a citrus coumarin derivative, is one of the promising chemopreventive agents against skin, tongue, esophagus and colon carcinogenesis in rodents. We reported previously that AUR suppresses superoxide anion (O(2)(-)) generation from inflammatory leukocytes in in vitro experiments. In the present study, we investigated the anti-inflammatory activities of AUR using a 12-O:-tetradecanoylphorbol-13-acetate-treated mouse skin model, and compared them with those of umbelliferone (UMB), a structural analog of AUR that is virtually inactive toward O(2-) generation inhibition. Double pre-treatments of mouse skin with AUR, but not UMB, markedly suppressed edema formation, hydrogen peroxide production, leukocyte infiltration, and the rate of proliferating cell nuclear antigen-stained cells. These inhibitory effects by AUR are attributable to its selective blockade of the activation stage, as revealed by single pre-treatment experiments. In a murine macrophage line, RAW 264.7, AUR significantly attenuated the lipopolysaccharide-induced protein expression of inducible isoforms of both nitric oxide synthase and cyclooxygenase, with decreased production of nitrite anion and prostaglandin E(2), and yet suppressed the release of tumor necrosis factor-alpha. Conversely, UMB did not show any inhibitory effect. This contrasting activity profile between AUR and UMB was rationalized to be a result of their distinct differences in cellular uptake efficiencies, i.e. the geranyloxyl group in AUR was found to play an essential role in incorporation. Thus, our findings indicate that AUR is an effective agent to attenuate the biochemical responsiveness of inflammatory leukocytes, which may be essential for a greater understanding of the action mechanism that underlies its inhibition of inflammation-associated carcinogenesis.

Topics: Animals; Anticarcinogenic Agents; Carcinogens; Cell Division; Coumarins; Cyclooxygenase 2; Dermatitis, Contact; Edema; Female; Hydrogen Peroxide; Isoenzymes; Leukocytes; Lipopolysaccharides; Macrophage Activation; Macrophages; Mice; Mice, Inbred ICR; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Prostaglandin-Endoperoxide Synthases; Skin; Skin Neoplasms; Superoxides; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha; Umbelliferones