A new flavonoid from Stellera chamaejasme L., stechamone, alleviated 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in a murine model

Stellera chamaejasme L. (family Thymelaeaceae), also known as 'Langdu', has been traditionally used to treat of skin-related diseases, such as, psoriasis and skin ulcers. The aim of this study was to identify the biologically active component of S. chamaejasme and evaluate its preventive effects on IL-4 and mast cell degranulation in RBL-2H3 cells and on the development of atopic dermatitis (AD) in 2,4-dinitrochlorobenzene (DNCB)-treated SKH-1 hairless mice. A novel flavonoid, genkwanin 5-O-xylosyl(1 → 2)glucoside (named stechamone), and three known compounds (umbelliferone, luteolin, and luteolin-7-O-glucoside) were isolated from the aerial parts of S. chamaejasme using chromatographic methods. Of these four compounds, stechamone most potently inhibited IL-4 production and mast cell degranulation in RBL-2H3 cells. Topical application of 0.5% stechamone improved atopic skin symptoms, including, erythema (redness), pruritus (itching), exudation (weeping), excoriation (peeling), and lichenification (skin thickening) in DNCB-treated AD mice by accelerating skin barrier recovery function and suppressing inflammatory cell infiltration. In addition, stechamone attenuated DNCB-induced increases in IL-4 (an inflammatory TH2 cytokine) expression and in serum IgE levels in our murine model of AD. DNCB induced AD-like skin lesions, but treatment with stechamone exhibited strong anti-atopic activity by regulating skin barrier function and reducing inflammatory responses. The results obtained suggest stechamone is a potential anti-atopic agent and treatment for skin inflammatory diseases.