Inhibitory Effect of Valencene on the Development of Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

Valencene (VAL) isolated from Cyperus rotundus possesses various biological effects such as antiallergic and antimelanogenesis activity. We investigated the effect of VAL on atopic dermatitis (AD) skin lesions and their molecular mechanisms. We topically applied VAL to 1-chloro-2,4-dinitrobenzene (DNCB) sensitized NC/Nga mice. Modified scoring atopic dermatitis index, scratching behavior, and histological/immunohistochemical staining were used to monitor disease severity. RT-PCR, western blotting, and enzyme-linked immunosorbent assay were used to determine the level of IgE, proinflammatory cytokines/chemokines production, and skin barrier proteins expression. Topical application of VAL significantly reduced AD-like symptoms and recovered decreased expression of filaggrin in DNCB-sensitized NC/Nga mice. The levels of serum IgE, IL-1β, IL-6, and IL-13 in skin/splenic tissue were reduced. In vitro studies using TNF-α and IFN-γ treated HaCaT cells revealed that VAL inhibited the exaggerated expression of Th2 chemokines including TARC/CCL17, MDC/CCL22, and proinflammatory chemokines such as CXCL8, GM-CSF, and I-CAM through blockade of the NF-κB pathway. In addition, expression of the skin barrier protein, involucrin, was also increased by VAL treatment. VAL inhibited the production and expression of proinflammatory cytokines IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These results suggest that VAL may serve as a potential therapeutic option for AD.