Disposition of carbon 14 labeled flavone in the rat

Svardal A.; Buset H.; Scheline R. R.

The excretion of radioactivity in the urine, bile, feces and respiratory CO2 was studied in rats given [2-14C]flavone (1 mmol/kg, per os). Complete excretion of the radioactivity in the urine (21%) and feces (78%) occurred within 5 days; the bulk of the radioactivity was excreted within 48 h. Excretion of radioactivity was extensive in bile and absent in respiratory CO2. Nearly 40% of the urinary radioactivity consists of neutral metabolites, of which 3'- and 4'-hydroxyflavone were the most prominent. These metabolites excreted in the bile, mainly in conjugated form. Urinary samples sometimes contained traces of 2'-hydroxyflavone and 3',4'-dihydroxyflavone. The major identified fecal metabolites were unchanged flavone and its 3'-hydroxy derivative.