The anti-inflammatory effects of new catechin derivatives in a hapten-induced mouse contact-dermatitis model

[Speaker] Eriko Nakano:1
[Co-author] Daisuke Kamei:1, Iyori Taki:1, Koji Karasawa:2, Kiyoshi Fukuhara:3, Shinichi Iwai:1
1:Department of Health and Regulatory Sciences, Showa University school of Pharmacy, Japan, 2:Department of Bioanalytical Chemistry, Showa University School of Pharmacy, Japan, 3:Department of Medical Chemistry, Showa University school of Pharmacy, Japan

Background: In recent Japan, catechin containing health foods had been widely used, and their effects were drawed attention. Several studies have examined anticancer effect, anti-obesity effect, anti-inflammatory effect and antioxidant effect of catechin. Contact dermatitis was a common skin disease. The guidelines recommend topical corticosteroids, but the treatment has restricting application sites to avoid cutaneous adverse events (eg, atrophy, telangiectasia). There was currently demand for the development of new treatments. Therefore, we focused on catechin, synthesized planar catechin (PC) from natural (+)-catechin and further chemically modified it and Methylated PC (MePC) and Acetylated PC (AcPC) were modified to increase lipid soluble. We intended to clarify the anti-inflammatory and antioxidant effects of new catechin derivatives.
Methods: The contact dermatitis model mice were used balb/c female mice (6-12 weeks old, n=6) for anti-inflammatory effects, mice were sensitized with 0.5% (v/v) DNFB (1-fluoro-2,4-dinitrobenzene) in acetone/olive oil (4/1, v/v) on abdominal skin. After five days, the ventral surfaces of the ears were challenged with 0.3% DNFB. Ear thickness were measured for each mice before elicitation and at various time periods after elicitation. Measurements were taken at a predetermined site using a micrometer. The difference in thickness was expressed as ear swelling. Antioxidant effect of new catechin derivatives: The antioxidant effects were examined about the ability to remove hydroxyl radical using Electron Spin Resonance(ESR).
Result: The induced ear swelling by DNFB application were suppressed (16-53 %) in AcPC treated ears application compared to a vehicle control. In particularly effects of anti-swelling were recognised within 24 hours. In vitro, antioxidant capacities were PC (44 %) > (+)-catechin (18 %) > AcPC (17 %) > MePC (-3 %).
Discussion: These results suggest that new catechin derivatives of AcPC would be a novel therapeutic tool for contact dermatitis. AcPC might control early inflammation on hapten-induced mouse contact dermatitis. AcPC showed anti-inflammatory effect despite its lower antioxidant capacity than PC. AcPC may be more effective for immediate-type allergy.

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