Antiallergic properties of tea components

摘要

The O-methylated catechin derivatives with potent anti-allergic effect were isolated form 'Tong ting" oolong tea by HPLC techniques. From NMR and FAB-MS analyses, the structures were elucidated as (-)-epigallocatechin-3-O-(3-O-methyl)gallate and (-)-epigallocatechin-3-O-(4-O-methyl)gallate. Oral doses of the catechin derivatives (5-50 mg/kg) significantly inhibited type I allergic (anaphylactic) reactions in mice sensitized with ovalbumin and Freund's incomplee adjuvant. These inhibitory effects exceeded that of the major tea catechin, (-)-epigallocatechin 3-O-gallate, which has knwon anti-allergic properties. These catechin derivatives had also potent inhibitory effects against mouse contact hypersensitivity to oxazolone in a type IV allergic model.