Studies on flavonoid metabolism. Excretion of m hydroxyphenylhydracrylic acid from (+) catechin in the monkey (Macaca iris sp.)

Abstract

Oral administration or intraperitoneal injection of (+) catechin to monkeys resulted in the excretion of 10 phenolic metabolites. The principal phenolic acid metabolite is m hydroxyphenylhydracrylic acid and the major lactone metabolite is δ (3 hydroxyphenyl) γ valerolactone. The m hydroxyphenylhydracrylic acid was shown to arise from β hydroxylation of m hydroxyphenylpropionic acid which is one of the metabolites of (+) catechin. The metabolites of (+) catechin are excreted both in the free and conjugated form. m Hydroxyphenylhydracrylic acid and δ (3 hydroxyphenyl) γ valerolactone amounted to about 4.3 and 7.6% of the administered dose, respectively. Oral administration and intraperitoneal injection of (+) [U 14C]catechin resulted in the urinary excretion of 53.5 and 50.2% of the dose, respectively. The radioactivity detected in the feces was between 0.8 and 2.2% of the dose. The species variation in the metabolism of (+) catechin is discussed.