In the present study, the catechin and theaflavin levels in three brands of green tea and four brands of black tea commercialized in Brazil were determined. The analytical methodology consisted of a very simple aqueous extraction and high performance liquid chromatography. A reverse phase Novapak C18 (3.9 mmx150 mm, 4 µm) column was used with a gradient of water and methanol, both in formic acid, as mobile phase. In green tea, the catechin contents (in mg/g of dry leaf) varied substantially: catechin, 0.8 to 2.8; epigallocatechin, 8 to 44; epigallocatechin gallate, 11 to 50; epicatechin, 2.3 to 8.5; and epicatechin gallate, 3.1 to 7.3. In the case of black tea, the concentrations (mg/g of dry leaf) of catechins were in the ranges of: 10 to 50 of epigallocatechin, 14 to 37 of epigallocatechin gallate, 5 to 9 of epicatechin and 10 to 21 of epicatechin gallate. The theaflavins had less variation: between 5 (for theaflavin 3'-gallate) to 13 mg/g (for theaflavin 3,3'-digallate) of dry leaf. Samples of teas widely consumed in Brasil (anise, camomile, lemon grass, peppermint, boldo, maté, green maté, apple and strawberry) were also investigated but no catechin or theaflavin was detected.
green tea; black tea; catechins; theaflavins; high performance liquid chromatography
