Abstract
Catechins, one of the main components in green tea extract, have antioxidative activity and immunomodulating activities, and play an important role in reducing the risk of disease. The most abundant catechins in a green tea extract are epigallocatechin gallate (EGCG) and epigallocatechin (EGC), and the EGCG/EGC ratio in a green tea extract was affected by the extraction temperature. We found that the cold water extract or the catechin mixture with a high EGC ratio induced greater immunoglobulin A (IgA) production by murine Peyer's patch (PP) cells. Here, we investigated the effect of cold water extract of green tea on salivaly sIgA levels in habitual green tea (hot water extract) drinker.
