Ishizuchi dark tea suppresses IgE-mediated degranulation of RBL-2H3 cells and nasal rubbing behavior of pollinosis in mice

• Published in: Journal of functional foods 2015-04, Vol.14, p.659-669
• Main Authors: Kondo, Michiyo, Nishi, Kosuke, Sugahara, Takuya
• Format: Article
• Language: English
• Subjects: Anti-allergic activity; Mast cell degranulation; Mice; Microorganism-fermented tea; RBL-2H3 cells; Theabrownin
• ISSN: 1756-4646; 2214-9414
• DOI: 10.1016/j.jff.2015.02.045

•Ishizuchi dark tea (IDT) is a microorganism-fermented tea produced in Ehime, Japan.•IDT suppressed degranulation of RBL-2H3 cells with no apparent cytotoxicity.•Theabrownins were found as the major bioactive substance in IDT.•IDT tended to inhibit phosphorylation of a tyrosine kinase Syk.•IDT suppressed an allergic symptom in Cry j1-induced pollinosis model mice. Ishizuchi dark tea is a microorganism-fermented tea produced in Ehime, Japan. We herein describe the anti-allergic effect of Ishizuchi dark tea. The water extract from Ishizuchi dark tea suppressed degranulation of RBL-2H3 cells in a dose-dependent manner with no apparent cytotoxicity. Fractionation and β-hexosaminidase release assay of the tea components revealed theabrownins as the major bioactive substance in Ishizuchi dark tea. Phosphorylation of Syk, a tyrosine kinase, tended to be suppressed by treating RBL-2H3 cells with theabrownins. In addition, Ishizuchi dark tea suppressed an allergic symptom in the Cry j1-induced pollinosis model mice. Taken together, these data indicated that Ishizuchi dark tea would be a beneficial functional food with an anti-allergic effect.