Formation of Glycyrrhizinic Acid in Glycyrrhiza glabra var. typica

Abstract

The distribution of glycyrrhizinic acid in the different organs of Glycyrrhiza glabra L. was determined. Highest concentrations were found in the main roots, lower concentrations in the lateral roots. The green parts of the plant were shown to contain no glycyrrhizinic acid. By encymatic hydrolysis of glycyrrhizinic acid with β-glucuronidase from bovine liver, a specific degradation of the molecule was achieved with the monoglucuronide of β-glycyrrhetinic acid as intermediate. Biosynthetic studies with roots of Glycyrrhiza glabra L. and sodium (2-¹⁴C) acetate, (U-¹⁴C) glucuronic acid and (U-¹⁴C) glucose as precursors resulted in an incorporation of these substrates into glycyrrhizinic acid. Acetate was found to be specifically incorporated into the aglycone moiety of the triterpene saponin and glucuronic acid mainly in the sugar moiety of the diglucuronide, respectively.