Effect on the Epigallocatechin Gallate/Epigallocatechin Ratio in a Green Tea (Camellia sinensis L.) Extract of Different Extraction Temperatures and Its Effect on IgA Production in Mice

We found that the epigallocatechin gallate (EGCG)/epigallocatechin (EGC) ratio in a green tea (Camellia sinensis L.) extract was affected by the extraction temperature. The EGCG/EGC ratio in the 4 degrees C extract was around 1:3-4, whereas in the 100 degrees C extract, it was around 1:0.7. Oral administration of the mixture with a high EGC ratio (1:2-3 = EGCG/EGC) resulted in greater IgA production by murine Peyer's patch cells.