Inhibitory Effects of Grewia tomentosa Juss. on IgE-Mediated Allergic Reaction and DNCB-Induced Atopic Dermatitis

Grewia tomentosa Juss. is a deciduous shrub that mainly grows in Asia. Despite studies of other Grewia species for treatment of various diseases, Grewia tomentosa Juss. has not been studied as a medicinal herb. This study evaluates the anti-allergic and anti-topic dermatitis activity of Grewia tomentosa Juss. ethanol extract (Gt-EE). The results show that Gt-EE suppressed IgE-antigeninduced beta-hexosaminidase release. The mRNA expression of IL-1 beta, IL-4, IL-5, IL-6, IL-13, TNF-alpha, MCP-1, and TSLP, which are involved in allergic responses, was inhibited by Gt-EE in IgE-stimulated RBL-2H3 cells. In addition, the phosphorylation of Syk, PLC gamma 1, PKG delta, PI3K, AKT, NF-kappa B p65, NF-kappa B p50, p38, JNK, and ERK1/2 was decreased by Gt-EE in these cells. Gt-EE also showed anti-inflammatory effects in in vivo mouse models. In passive cutaneous anaphylaxis (PCA), a commonly used mouse model, Gt-EE decreased the allergic response, infiltration of mast cells, and mRNA level of IL-4. Furthermore, Gt-EE ameliorated symptoms of DNCB-induced atopic dermatitis (AD). In DNCB-induced AD, Gt-EE suppressed the increase in mast cells, serum IgE level, expression of allergic mediators (IL-1 beta, IL-4, IL-5, IL-6, TNF-alpha), and phosphorylation of proteins (I kappa B alpha, NF-KB p65, NF-kappa B p50, p38, JNK, and ERK1/2) implicated in allergic reactions