[Antioxidant reactions and activities of teas and wines by the cumene hydroperoxide/hemoglobin * methylene blue method].

Background: We reported a new method using cumene hydroperoxide to determine the antioxidant activity of polyphenols.

Methods: We measured antioxidant activities of a variety of different teas and wines by the cumene hydroperoxide/hemoglobin * methylene blue method. The activities of teas were observed by adding 100 ml of boiling water to 2g of tea leaves. The wine samples were mainly diluted 10 times.

Results: The average level of antioxidant activity of teas was as follows: wild plants (n = 6) were 59 micromol/l, heated green (n = 3) was 400 micromol/l, green (n = 8) was 550 micromol/l, powdered green (n = 2) was 960 micromol/l, and black (n = 11) was 405 micromol/l. The antioxidant activity of wines was as follows: red (n = 7) was 1,920 micromol/l, white (n = 7) was 1,010 micromol/l, additive-free red (n = 6) was 658 micromol/l, and additive-free white (n = 6) was 118 micromol/l. The correlation between the concentration of teas or wines and antioxidant activity was not a linear type. For this reason, the tea and wine were measured under comparable conditions. The concentration of free sulfur dioxide contained within red wine was 20 mg/l and, white wine was 55 mg/l. The apparent-antioxidant activity of these concentrations of free sulfur dioxide was 234 micromol/l and 651 micromol/l.

Conclusions: Tea is the national drink of Japan, green tea and heated green tea are particularly favored. The antioxidant activities of these teas were lower than that of red wine. However larger quantities of tea than wine are consumed every day. Therefore, we concluded that the total antioxidant activity of tea is the same or higher than that of red wine.