Sasa veitchii extracts suppress 2,4-dinitrofluorobenzene-induced contact hypersensitivity in mice

We examined the therapeutic effect of the extract from Sasa veitchii leaves (Sasa extract: SE) on the allergic skin inflammation model. SE derived from 0.141 g (low dose) or 0.562 g (high dose) of the leaves was administered orally for 15 days. High dose of SE suppressed ear swelling response induced by repeated 2,4-dinitrofluorobenzene (DNFB) paintings, and both low and high doses of SE reduced infiltration of immune cells into the ear dermis. Although the number of T cells, Treg, CD4⁺T cells and CD8⁺T cells in draining lymph nodes (dLNs) was not changed by SE, IFN-γ secretion from dLN induced by concanavalin A or 2,4-dinitrobenzenesulfonic acid was suppressed by a high dose of SE while IL-10 levels remained unchanged. These results suggest that SE suppresses allergic skin inflammation via reducing IFN-γ secreted from immune cells, especially T cells.