Tea, brewed from the leaves of the Asian evergreen tree <i>Camellia sinensis</i>, has long been considered to have medicinal properties. Modern research has attempted to account for some of these properties, and discovered antioxidants which could potentially mitigate the effects of cell-damaging free radicals. Tea antioxidants include phenolic compounds such as flavanols, flavandiols, and phenolic acids. Among the most important phenolics in tea are the catechins, which include catechin, epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG), and theaflavins such as theaflavin gallate. It is generally recognized that the content of catechins and theaflavins present in teas of various styles differs, with green teas exhibiting the highest total phenol content (TPC) but the literature lacks consensus on catechin composition of green, white, oolong, black, and puer teas. In our preliminary studies, we used spectrometry to determine TPC in six sets of loose-leaf green teas of various styles and high-pressure liquid-chromatography (HPLC) to identify and quantify the amount of each catechin molecule in these same teas. For all green teas tested, ECGC was the predominant catechin, while other catechins varied significantly. Caffeine content in our samples was also found to be much higher than reported using previous protocols, ranging from 320 to 425 ppm. Ongoing HPLC studies aim to quantify the caffeine and catechins in white, green, oolong, black, and puer teas to assess the impact of alternative leaf processing on these medicinally active compounds.

Quantification of catechin compostion in <i>Camellia sinensis</i>: Comparing different leaf processing methods

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Quantification of catechin compostion in Camellia sinensis: Comparing different leaf processing methods