Using LC-MS to Determine Amounts of Green Tea Catechins in Human Plasma

Catechins in green tea are known to have many biological and pharmacological benefits. For example, they demonstrate anticancer, antioxidant, and anti-obesity effects, and reduce fat and sugar levels in the blood. Researchers believe that oral ingestion of highly concentrated tea catechins can help people lose weight and reduce the risk of contracting lifestyle-related diseases. To better understand the molecular dynamics of catechins in the human body when they are ingested in tea, it is necessary to determine the amounts of catechins in the blood (eight types of epi- and non-epi-catechins). Using liquid chromatography and electrospray ionization mass spectrometry (ESI-MS), we developed a highly sensitive and highly selective method of measuring the eight types of catechins found in green tea. We were able to detect all eight types in the plasma of people who drank commercial tea beverages, and could trace changes in catechin concentrations over time (J Chromatogr B 834 (2006) 26). This method has made it possible to study the kinetics of green tea catechins inside the human body.