| Summary: | Allergies are immediate hypersensitive responses to antigens and IL‐4 is involved in the initiation and development of allergic responses. The present study was undertaken to examine whether ramalin, an antioxidant compound from the Antarctic lichen Ramalina terebrata , has an inhibitory effect on allergic response in TNF‐α‐stimulated HaCaT and RBL‐2H3 cells. In this study, the results of Real‐Time PCR analysis showed that mRNA levels of IL‐18, MCP‐1, RANTES and CCL17 were suppressed by ramalin in TNF‐α‐treated human keratinocyte (HaCaT) cells. Western blot analysis also indicated that ramalin inhibited the nuclear translocation of NF‐κB and phosphorylation of MAP kinases induced by TNF‐α. These results suggest that ramalin inhibits TNF‐α‐stimulated chemotactic cytokines through the suppression of NF‐κB signaling pathways and MAP kinase pathways. In addition, Real‐Time PCR analysis and ELISA showed that ramalin suppressed the mRNA levels and secretion of IL‐4. Expression of NFAT2 was also attenuated by ramalin in antigen‐mediated rat basophilic leukemia (RBL‐2H3) cells. Taken together, these results suggest that ramalin has an anti‐allergic effect and is a candidate for the therapeutic agent to treat allergy symptoms.
|
|---|