Platycodon grandiflorus alleviates DNCB-induced atopy-like dermatitis in NC/Nga mice

Objective: To investigate the therapeutic effect of crude extract from Platycodon grandiflorum (PG) roots on atopic dermatitis (AD)-like skin lesions in NC/Nga mice. Materials and Methods: To develop atopic dermatitis-like lesions, 200 μl of 0.3% 1-chloro-2, 4-dinitro benzene (DNCB) in acetone/olive oil (3:1) was applied 3 times a week for 2 weeks on the shaved skin of their backs. PG extract was dissolved in saline and orally administrated at concentrations of 300 and 500 mg/kg every day for 2 weeks. The therapeutic effect of PG on AD-like skin lesions was assessed by measuring skin severity scores and epithermal thickness, serum total immunoglobulin (Ig) E, histopathological findings for inflammatory cells including mast cells, macrophage and T cells, and mRNA expression of various cytokines related to the inflammatory and allergic response. The significance of inter-group differences was analyzed using the ANOVA test. Data were considered to be significant when P < 0.05 or P < 0.01. Results: Oral treatment of PG suppressed AD-like skin lesions according to the assessment of skin severity and epithermal thickness in the DNCB-treated NC/Nga mice. This alleviation was further correlated with a reduction of elevated serum total IgE or cytokine mRNA in the PG-treated group compared with vehicle-treated positive group. In addition, infiltrated inflammatory cells decreased on the skin lesions compared with vehicle-treated group. Conclusion: These results suggest that PG may have a potential therapeutic effect for AD via the inhibition of both inflammatory and allergic reaction.