Inhibitory effect of Japanese black vinegar on IgE-mediated degranulation of RBL-2H3 cells and a murine model of Japanese cedar pollinosis.

Japanese black vinegar (JBV) is a traditional vinegar manufactured with steamed unpolished rice. After screening, beneficial effects of JBV on IgE-mediated allergic responses were found. In this study, acetic acid-free JBV was used to evaluate its antiallergic effects. JBV suppressed degranulation of rat basophilic leukemia RBL-2H3 cells in a dose-dependent manner without cytotoxicity. The inhibitory effect of JBV on the degranulation seemed to be caused by the bioactive ingredients other than proteins, because the activity was not affected by heat treatment or protease digestion. JBV inhibited the elevation in the intracellular Ca2+ concentration induced by antigen. Immunoblot analysis revealed that JBV suppresses degranulation of RBL-2H3 cells by downregulated phosphorylation of PI3K, Akt, and PLCγ1. In addition, oral administration of JBV significantly suppressed passive cutaneous anaphylaxis reaction in mice and an allergic symptom in Cry j1-induced pollinosis model mice. Thus, JBV has a potential as a health-promoting food with the antiallergy effect.