Analysis of (+)-catechin, (-)-epicatechin and their 3 '- and 4 '-O-methylated analogs - A comparison of sensitive methods

(+)-Catechin and (-)-epicatechin are found in many foods and may have impor tant effects on human health. These compounds, like many other catechols, a re thought to be converted to methylated metabolites after ingestion. This paper describes the synthesis of the 3'- and 4'-methyl ethers and their una mbiguous identification. These products, along with catechin, epicatechin a nd an internal standard, (+)-taxifolin, were separated using RP-HPLC with u ltraviolet, electrochemical and fluorescence detection. The trimethylsilyla ted derivatives of the seven compounds were also separated by GC with mass spectrometric detection. The limits of detection and selectivity of the ana lytical methods were compared with respect to their application in complex matrices such as human plasma. (C) 1999 Published by Elsevier Science BN. A ll rights reserved.