Inhibitory effect of Alpinia katsumadai on atopic dermatitis-like skin lesions in NC/Nga mice

Alpinia katsumadai Hayata (AKH) is used traditionally as an herbal medicine in China and Korea. We assessed the effects of AKH extract on the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW 264.7 cells, thymus- and-activation-regulated chemokine (TARC/CCL17) in HaCaT cells and histamine level in HMC-1 cells. Atopic dermatitis was induced by topical application of house dust mites for 4 weeks, and the protective effects of AKH extract were investigated by measuring the severity of the skin reaction on the back and ears, and plasma levels of immunoglobulin E (IgE) and histamine. AKH extract suppressed the production of NO and PGE₂ in RAW 264.7 cells, TARC in HaCaT cells and histamine in HMC-1 cells in a dose-dependent manner. The severity of dermatitis, including erythema/hemorrhage, edema, erosion and scaling, and plasma levels of IgE and histamine were lower in NC/Nga mice with atopic dermatitis, treated with AKH extract than in untreated mice. AKH extract reduced the histological manifestations of atopic dermatitis-like skin lesions such as erosion, hyperplasia of the epidermis and dermis, and inflammatory cell infiltration on the skin of the back and ear. These results suggest that AKH extract inhibits the development of house dust mite-induced atopic dermatitis in NC/Nga mice. Additionally, we performed simultaneous determination of alpinetin, pinocembrin, and cardamonin in AKH extract using the HPLC-PDA.

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