Studies on flavonoid metabolism. Metabolism of (+)-[14C]catechin in the rat and guinea pig

Abstract

1. The fate of (+)-[U−14C]catechin and (+)-[ring A−14C]catechin has been studied in the guinea pig and rat. 2. (+)-[U−14C]Catechin was shown to give rise to labelled phenolic acids, labelled phenyl-γ-valerolactones and 14CO2. 3. (+)-[ring A−14C]-Catechin did not give rise to labelled phenolic acids, but labelled phenyl-γ-valerolactones were detected together with a higher proportion of 14CO2. 4. Administered [14C]δ-(3-hydroxyphenyl)-γ-valerolactone gave rise to labelled m-hydroxyphenylpropionic acid in the rat whereas administered [14C]m-hydroxyphenylpropionic acid gave rise to a compound yielding labelled m-hydroxybenzoic acid on hydrolysis. 5. The distribution of radioactivity in the urine and faeces of (+)-[14C]catechin-fed animals is described; a high proportion of residual radioactivity was found in urine that had been exhaustively extracted with diethyl ether.