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Objectives : Stevia rebaudiana is a well-known herbal sweetener in the Korea, Japan and China, and its medical uses were originated from countries in South America. Although it has been shown the various medical effects of S. rebaudiana including contraception and treatment of human diseases such as hyperglycemia, it has almost not been studied about the efficacy of S. rebaudiana methanolic extract (SRE) on the acute inflammation and its action mechanism.Methods : To investigate the anti-inflammatory effects of SRE, we treated SRE and examined the level of inflammatory mediators in LPS-stimulated Raw264.7 cells.Results : Treatment of macrophage with LPS markedly induced the production of NO, PGE2 and pro-inflammatory cytokines. Pretreatment of SRE blocked the induction of inflammatory mediators and the expression of iNOS protein. More importantly, LPS-induced phosphorylation of IκB-α was suppressed by the treatment of SRE, suggesting SRE inhibition of NF-κB activation. Furthermore, SRE blocked LPS-induced phosphorylation of MAPKs.Conclusions : SRE inhibited the induction of NO, PGE2 and pro-inflammatory cytokines in Raw264.7 cells. SRE's effect may be mediated with its inhibition of NF-κB activation and MAPK phosphorylation, which suggests its uses as an anti-inflammatory agents.

Abstract.[Purpose] The purpose of the present study was to investigate the effect of a magnetic infrared laser (MIL) on the 2, 4-dinitrofluorobenzene (DNFB)-induced contact dermatitis, type I allergic mouse model. [Subjects] Male ICR mice.[Methods] Contact dermatitis was induced by sensitization with dinitrophenyl-derivatized ovalbumin (DNP-OVA) and DNFB challenge as antigen. MIL radiation doses of 1.33, 2.66 and 6.65 J/cm 2 were given, once a day for 7 continuous days, to DNP-OVA sensitized mice and compared with 15 mg/kg dexamethasone (intraperitoneal treatment). The edematous changes and scratching behavior were measured together with ear histopathological observations. [Results] Immediately after DNFB challenge to the ear or paw of DNP-OVA sensitized mice, increases of ear and paw thicknesses and weights were detected as well as anterior ear skin (dermis to epidermis) thickness and paw scratching behavior increases. However, these DNFB-induced increases of edematous changes and scratching behavior were significantly and dose-dependently decreased by MIL irradiation.[Conclusion] The results obtained in this study suggest that MIL radiation has relatively favorable effects on allergic dermatitis, and MIL therapy may represent an alternative approach for the treatment of allergic cutaneous diseases.

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