November 5/News of Science -- According to recent research from Sendai, Japan, "Based on the ratios of (-)-epigallocatechin-3-gallate (EGCG) and caffeine (CAF) levels found in commercial tea drinks, EGCG and CAF were co-administered to human volunteers at various EGCG/CAF ratios, and plasma EGCG was determined by high performance liquid chromatography with chemiluminescence detection. As for the results, in plasma taken after ingestion of a beverage containing 95mg of EGCG alone, the area under the plasma EGCG concentration-time curve (AUC) was 857ng.h/ml."

"A higher AUC (1,370ng.h/ml) was observed when subjects ingested a beverage containing EGCG (95mg) and a low amount of CAF (40mg). In the case of ingestion of a beverage containing EGCG (95mg) and a high amount of CAF (180mg), the AUC tended to be somewhat higher (1,165ng.h/ml) but not significantly so, compared with the beverage with EGCG alone," wrote K. Nakagawa and colleagues, Tohoku University.

The researchers concluded, "These findings (modulation of plasma EGCG level by CAF) provide ideas for modulating the bioavailability of tea catechins, which can be applied to tea-related drinks and foods."

Nakagawa and colleagues published their study in Bioscience Biotechnology and Biochemistry ("Effects of Co-Administration of Tea Epigallocatechin-3-gallate (EGCG) and Caffeine on Absorption and Metabolism of EGCG in Humans." Bioscience Biotechnology and Biochemistry, 2009;73(9):2014-2017).

For additional information, contact K. Nakagawa, Tohoku University, Graduate School Agriculture Science, Food & Biodynam Chemical Laboratory, Sendai, Miyagi 9818555, Japan.

From the November 9, 2009, Prepared Foods E-dition