Metabolic and glucosuria studies on naringin and phloridzin.

The metabolic fate of three flavonoids, hesperidin, eriodictyol and diosmin, isolated from citrus fruits was reported recently by Booth, Jones, and DeEds (2). A fourth flavonoid, naringin, which can be isolated readily from grapefruit, was also investigated as a potential precursor of metabolites in the urine of the rat and human. Because phloridzin is similar to naringin in structure, the former is included in the present studies. Phloridzin is the glucoside of a chalcone whose aglycon is phloretin, the latter being identical with dihydronaringenin (Fig. I). It is well known that phloridzin can be used as a means of producing glucosuria experimentally in animals. Since phloridzin and naringin are closely related structurally, the question is raised naturally as to whether naringin may also cause the excretion of sugar in the urine. We are not aware of any published reports bearing on this subject.