- Evaluate the effects of high-level oral consumption of defined green tea (four 12-oz servings/day) or polyphenon E capsules (4 capsules/day) on markers of cellular oxidative damage, as measured by 8-hydroxydeoxyguanosine (8-OHdG) and 8-F_2-isoprostanes (8-epi-PGF2) in former smokers with chronic obstructive pulmonary disease.