Tea, a drink prepared from the leaves of <i>Camellia sinensis</i>, is considered to have both health benefits and risks related to the compounds such as catechins and methylxanthines, constituents that can vary according to processing technique. For example, white tea, green tea, oolong tea, black tea, and puer tea are all made from the same leaf type, but are manufactured with varying degrees of fermentation (oxidation). In this study, we sought to characterize the phenolic content across tea processing methods. We also examined the levels of methylxanthine alkaloids, a class of psychoactive compounds. We measured concentrations of the polyphenolic compounds catechin, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate (EGCG), theaflavin, theaflavin-3-gallate, and theaflavin 3,3’ digallate by High Performance Liquid Chromatography (HPLC). These compounds are antioxidants which could aid in neutralizing free radicals formed by cell processes. The less fermented teas, such as green tea, are expected to have a greater proportion of catechins relative to the more complex, oxidized polyphenols including theaflavins and thearubigins that would be more abundant in oolong and black teas. We also quantified the methylxanthines theobromine, theophylline, and caffeine. While catechins vary depending on processing method, methylxanthines are expected to be consistent across tea types. Preliminary data showed highly variable levels of catechins across processing methods, but the total phenolic content was found to be highest in green tea. In the ongoing work, we are measuring levels of the individual catechins, theaflavins, and methylxanthines across several samples from each of the five tea types prepared using a standardized brewing protocol.

Analysis of catechin and methylxanthine composition in tea (<i>Camellia sinensis</i>) by high pressure liquid chromatography

255th National Meeting (2018)

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Analysis of catechin and methylxanthine composition in tea (Camellia sinensis) by high pressure liquid chromatography