Green tea (Camellia sinensis)
Plasma pharmacokinetics of catechin metabolite 4'-O-Me-EGC in healthy humans CSV JSON


Tea is an infusion of the leaves of the Camellia sinensis plant and is the most widely consumed beverage in the world after water. Green tea contains significant amounts of polyphenol catechins and represents a promising dietary component to maintain health and well-being. Epidemiological studies indicate that polyphenol intake may have potential health benefits, such as, reducing the incidence of coronary heart disease, diabetes and cancer. While bioavailability of green tea bioactives is fairly well understood, some gaps still remain to be filled, especially the identification and quantification of conjugated metabolites in plasma, such as, sulphated, glucuronidated or methylated compounds.


In the present study, we aimed to quantify the appearance of green tea catechins in plasma with particular emphasis on their methylated forms.


After feeding 400 mL of green tea, 1.25% infusion to 9 healthy subjects, we found significant amounts of EC, EGC and EGCg in plasma as expected. EGC was the most bioavailable catechin, and its methylated form (4'-O-Me-EGC) was also present in quantifiable amounts. Its kinetics followed that of its parent compound. However, the relative amount of the methylated form of EGC was lower than that of the parent compound, an important aspect which, in the literature, has been controversial so far. The quantitative results presented in our study were confirmed by co-chromatography and accurate mass analysis of the respective standards. We show that the relative abundance of 4'-O-Me-EGC is ~40% compared to the parent EGC.


4'-O-Me-EGC is an important metabolite derived from catechin metabolism. Its presence in significant amounts should not be overlooked when assessing human bioavailability of green tea.




1 . Pharmacokinetics after Single Dose of Green Tea (id=NPDI-cNMCFg)

In Vivo Pharmacokinetics Study

Catechin and (-)-epicatechin gallate were not observed in plasma after green tea consumption.


Sample Compound measured Value Measurement Study sequence Additional information N replicates

Experimental Conditions

One subject dropped out and two others had an incomplete set of data (missing blood sample).

Single dosing


Healthy volunteers


12 enrolled, 9 completed the study

Pharmacokinetic (PK) Sampling Information

0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 10, 11, and 12 h

Drug or Natural Product Administration

Natural Product Administration


1.25% (w/v) green tea infusion

400 mL


single dose

Natural Product Characteristics


Pharmacodynamics (PD) & Adverse Events

Not provided.

Not provided.