Mass Fragmentographic Determination of Ferulic Acid in Plasma after Oral Administration of γ-Oryzanol

A mass fragmentographic method for the quantitative determination of ferulic acid, a main metabolite of γ-oryzanol in rabbit and dog plasma, was developed. After its isolation by Amberlite XAD-2 chromatography and by solvent extraction, ferulic acid was converted to the heptafluorobutyryl ethyl ester derivative and analyzed by using 4-hydroxy-3-trideuteromethoxycinnamic acid (ferulic acid-d3) as an internal standard. The recovery of ferulic acid from plasma samples was 100.5±4.5% (mean±standard deviation, n=20) in the range of 5.0-150.0 ng/ml plasma. γ-Oryzanol was administered orally to rabbits and dogs at doses of 25, 50 and 100 mg/kg body weight as a solution of sesame oil, and then the plasma concentrations of ferulic acid were determined by mass fragmentography. A good correlation between the administered dose of γ-oryzanol and the area under the concentration curve (AUC) of ferulic acid was obtained in both animals, so the AUC of ferulic acid may be used as an index for estimating the extent of gastrointestinal absorption of γ-oryzanol.