Identification of urinary metabolites of flavanone in the rat.

The urinary metabolites of flavanone in the rate were investigated using a gas chromatographic mass spectrometric method employing an OV-1 capillary column. Forty-three metabolites were detected and the most prominent of these were identified. The most common metabolic reactions were reduction of the keto group and hydroxylation at the 3- or 6-positions. Little hydroxylation occurred in ring B. The major metabolites were flavan-4 alpha-ol, trans-3-hydroxyflavan-4 beta-ol, 6-hydroxyflavanone and 6-hydroxyflavan-4 beta-ol. Gas chromatography analysis of underivatized flavanone metabolites, especially with stainless steel columns, results in the formation of dehydrated products including flavone, flav-3-ene and flavanone itself.