Plants of the genus Wikstroemia are traditionally used to treat inflammatory diseases like
bronchitis and
rheumatoid arthritis. In the present study, the anti-atopic effects of an EtOH extract of Wikstroemia dolichantha (WDE) on
oxazolone- and
DNCB (2,4-dinitrochlorobenzene)-induced
dermatitis in mice were investigated. Both ears of BALB/c mice were exposed to
oxazolone, and dorsal skins of SKH-1 hairless mice were sensitized with
DNCB to induce acute eczematous atopic skin lesions. 1% WDE was applied daily to
oxazolone- and
DNCB-induced AD mice for two or three weeks, respectively. Total
IL-4 and
IgE concentrations in serum, transepidermal water loss (TEWL) and skin hydration were assessed. High-performance liquid chromatography/mass spectrometry (HPLC/MS) was used to determine the composition of WDE. Dermal application of 1% WDE grossly and histopathologically improved
oxazolone- and
DNCB-induced AD skin symptoms. Epidermal thickness and mast cell infiltration were significantly lower in animals treated with WDE than in vehicle controls. Furthermore, in addition to reducing
DNCB-induced increases in serum
IL-4 (
interleukin 4) and
IgE (
immunoglobulin E) levels, WDE also decreased TEWL and increased skin hydration (indicative of improved skin barrier function). The four
flavonoids taxifolin,
aromadendrin, padmatin and
chamaejasmine were tentatively identified in WDE by HPLC-DAD/QTOF-MS. The above results show WDE protected against
oxazolone- and
DNCB-induced AD in mice by down-regulating the TH2-associated
cytokine IL-4 and improving skin barrier function and suggest WDE might be useful for the management of
atopic dermatitis.