All experiments used 25 ml sterile polystyrene tissue culture flasks with a vented blue plug seal cap (Beckton Dickinson, Franklin Lakes, NJ, Cat. No. 353107). Each flask contained stock solution with or without epicatechin in concentrations of 50 mM (five flasks for each epicatechin and five flasks for control) and 25, 75 and 100 mM (three flasks for each epicatechin and three flasks for control). Cells (0.25 · 10 6 ) suspended in 10 ml of the RPMI-1640-FBS solution described above were transferred to each flask and allowed to grow until control cells reached confluency. The cells were detached with sterile EDTA-dextrose at 37 C for 5 min, recovered with cold RPMI-1640-FBS medium and resuspended in the same medium.