Biol. Pharm. Bull. 30(5) 922—927 (2007)

tries. Most allergic reactions are mediated by allergen-specific IgE antibodies. Therefore, development of a method for inhibiting allergen-specific IgE production is a useful approach to prevent food-allergic diseases. IgE synthesis is considered to be caused by development and activation of T helper-2 (Th2) cells and B cells. This specific Th2 cell produces predominantly interleukin (IL)-4 and IL-5. IL-4 plays a crucial role in inducing class switching of IgM into IgE isotype and the IgE production. IL-5 enhances IL-4-dependent IgE production. In contrast, the T helper 1 (Th1) cells mainly secrete cytokines such as IL-2 and interferon (IFN)-g that inhibit IgE and IgG1 secretion and enhance IgG2a secretion. Thus, shifting the balance from Th2 to Th1 dominance should be a rational strategy to prevent IgE-mediated allergic diseases. The skins of mature peanuts (Arachis hypogaea L.) are particularly rich in procyanidins. They primarily contain A type procyanidins, in which the subunits are connected by both 4b →8 carbon bonds and 2b → O7 ether bonds to form the A1 dimer and trimer. Peanut skins are used to treat chronic haemorrhage and bronchitis in Chinese traditional medicine. Six A-type proanthocyanidins and flavonoids have been isolated from the water-soluble phenolic fraction from the skin of the mature seed of the peanut, Arachis hypogaea. In this study, we investigated the effect of oral administration of aqueous extract from peanut skin on allergic mediators production in mice sensitized with ovalbumin (OVA). MATERIALS AND METHODS