CONTENT OF POTENTIALLY ANTICARCINOGENIC FLAVONOIDS OF TEA INFUSIONS, WINES, AND FRUIT JUICES

The content of the potentially anticarcinogenic flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin of commonly consumed beverages was determined by RP-HPLC with UV detection. Flavonoid levels in beer, coffee, chocolate milk, and white wine were below 1 mg/L. Twelve types of tea infusion, six types of wine, apple juice, tomato juice, grape juice, orange juice, grapefruit juice, and lemon juice were analyzed. No luteolin or apigenin were detected in any of the beverages. In red wines and in grape juice quercetin and myricetin levels varying from 4 to 16 mg/L and from 7 to 9 mg/L, respectively, were detected. Quercetin levels in fruit juices were generally below 5 mg/L except for lemon juice (7 mg/L) and tomato juice (13 mg/L). In black tea infusions quercetin (10-25 mg/L), kaempferol (7-17 mg/L), and myricetin (2-5 mg/L) were detected. Flavonoid levels in green tea were comparable to those in black tea. The flavonoid content of tea prepared with tea bags was generally higher than that of tea prepared with loose leaves. Together with data on the flavonoid content of vegetables and fruits published previously (Hertog et al. J. Agric. Food Chem. 1992, 40, 2379-2383), these data provide a base for an epidemiological evaluation of the potentially anticarcinogenic effects of flavonoids.