SEASONAL-VARIATION OF GLYCYRRHIZIN AND ISOLIQUIRITIGENIN GLYCOSIDES IN THE ROOT OF GLYCYRRHIZA-GLABRA L

The time courses of the glycyrrhizin and isoliquiritigenin glycoside c ontents in the thickening roots of licorice, Glycrrhiza glabra L., hav e been determined. The glycyrrhizin content in 1-year-old roots rapidl y increased from October to November, whereas the isoliquiritigenin gl ycoside content increased up to October. In 3-year-old plants, althoug h the isoliquiritigenin glycoside content rapidly increased from June to July, the glycyrrhizin content did not show any significant increas e from May to august. The glycyrrhizin content increased during the se nescence of the aerial parts as well as during the early stage of shoo t elongation. The incorporation of [C-14]mevalonic acid into the glycy rrhizin fraction by the root segments was high in May, June and Septem ber, and low in August and winter. These results indicated that the bi osynthesis of glycyrrhizin is differently regulated from that of isoli quiritigenin glycoside in the thickening root of G. glabra.