Abstract
Glycyrrhizin (GL) was hydrolyzed to glycyrrhetic acid (GA), glycyrrhetic acid mono-β-D-glucuronide (GAMG) or both by glucuronidases in various organs of rat. GL β-D-glucuronidase I, hydrolyzing GL to GA; GAMG β-D-glucuronidase, hydrolyzing GAMG to GA; and 3α-hydroxyglycyrrhetinate (3α-hydroxyGA) dehydrogenase, oxidizing 3α-hydroxyGA to 3-oxo-GA were found in the organs of this animal. GL β-D-glucuronidase II was distributed in the lysosomal fraction of all organs except brain; 3α-hydroxyGA dehydrogenase was distributed in the microsomal fraction of the liver; but other enzymes were distributed in the nuclear, lysosomal, microsomal and soluble fractions of a variety of organs. GL β-D-glucuronidase I, GL β-D-glucuronidase II and GAMG β-D-glucuronidase activities in a mixture of lysosomes and microsomes of rat liver exhibited different patterns on hydroxyapatite column chromatography. These results showed the metabolic pathways of GL to be of two types : a β-D-glucuronidase hydrolyzing GL to GA, and the other consisting of two different β-D-glucuronidases hydrolyzing GL to GAMG and GAMG to GA.
