1-Furan-2-yl-3-pyridin-2-yl-propenone (FPP-3) has been characterized to have an anti-inflammatory activity through the inhibition of the production of nitric oxide and tumor necrosis factor-alpha. In the present studies, the phase 1 metabolism of FPP-3 was investigated in rat liver microsomes and cytosols. When FPP-3 was incubated with rat liver microsomes and cytosols in the presence of NADPH, 2 major peaks were detected on a liquid chromatography/electrospray ionization-mass spectrometry. Two metabolites (i.e., M1 and M2) were characterized as reduced forms on propenone: M1 (1-furan-2-yl-3-pyridin-2-yl-propan-1-one) was the initial metabolite and M2 (1-furan-2-yl-3-pyridin-2-yl-propan-l-ol) was a secondary alcohol believed to be formed from M1.