抄録
The prevalence of allergic diseases including asthma, atopic dermatitis and allergic rhinitis has increased in Japan as well as other developed countries during the last two decades. Although allergic diseases have not been recognized as life-style related diseases so far, dietary changes were recently proposed to be associated with this increase. Indeed some nutrients in foods or drink possess anti-allergic or allergy-promoting activities. Flavonoids, ubiquitously present in vegetables, fruits and teas, are shown to have anti-allergic activities such as inhibition of histamine release, synthesis of IL-4 and IL-13 and CD40 ligand expression by basophils and mast cells. Among flavones, luteolin, apigenin and fisetin are the strongest inhibitors of IL-4 production with an IC50 value of 2-5μM and quercetin and kaempferol showed a substantial activity with an IC50 value of 15-18μM. Administration of flavonoids into atopic dermatitis-model mice prevented the onset of dermatitis and ameliorated the severity of dermatitis, depending on the administration period. In addition a preliminary trial of flavonoids for adult patients with atopic dermatitis showed a significant effect. Moreover, recent epidemiological studies reported that a low incidence of asthma was significantly observed by a population with a high intake of flavonoids. Thus, this evidence raises a possibility that an appropriate daily intake of flavonoids may be a dietary menu for a complementary and alternative medicine and a preventative strategy for allergic diseases.
