The metabolism of γ-oryzanol was investigated in rabbit after oral administration of γ-oryzanol-14C (triterpenyl ester of ferulic acid-3-14C) (40 mg/kg). The radioactivity excreted in the urine for 48 hr was 6.4% of the administered dose and unchanged γ-oryzanol was not detected in the urine, the in situ absorption experiment suggested that γ-oryzanol was not metabolized in the intestinal tract and absorded as an intact form. Only acid-extracted fraction of the urine contained the radioactivity, and ferulic acid, vanillic acid, acetovanillone, hippuric acid and vanilloylglycine (glycine conjugate of vanillic acid) were identified as the major urinary metabolites of γ-oryzanol. On the basis of these data, metabolic pathway of γ-oryzanol in rabbit was postulated.
