Survey of Glycyrrhizae Radix resources in Mongolia: chemical assessment of the underground part of Glycyrrhiza uralensis and comparison with Chinese Glycyrrhizea Radix

Abstract

In order to reveal the chemical characteristics of Glycyrrhiza uralensis growing in Mongolia and to clarify whether it can be the source of Glycyrrhizae Radix used in Japan, eight major bioactive constituents in the underground parts of G. uralensis collected in Mongolia were quantitatively analyzed and compared with Glycyrrhizae Radix produced in China. Most of the 15 samples from eastern, southern and western parts of Mongolia contained 26.95-58.55 mg/g of glycyrrhizin, exceeding the criterion (25 mg/g) assigned in the Japanese Pharmacopoeia. The sample collected in Tamsagiyn hooly, Dornod province, in eastern Mongolia was of the highest content 58.55 mg/g. The contents of three flavanone constituents (liquiritin apioside, liquiritin and liquiritigenin) and three chalcones (isoliquiritin apioside, isoliquiritin and isoliquiritigenin) varied significantly according to collection places; the subtotal of the three flavanones ranged from 3.00 to 26.35 mg/g, and the subtotal of the three chalcones ranged from 1.13 to 10.50 mg/g. The content of glycyrrhizin and subtotal contents of flavanones and chalcones in the underground parts of G. uralensis from Mongolia were obviously lower than wild samples, but higher than cultivated samples derived from the same species produced in China. Glycycoumarin, a species-specific constituent of G. uralensis, was detected in all Mongolian samples. Its contents in samples from eastern Mongolia, Sergelen and Tamsagiyn hooly of Dornod province were very high and were compatible with Tohoku-kanzo derived from wild Chinese G. uralensis. The present study suggested that Mongolian G. uralensis could be a source of Glycyrrhizae Radix, mostly of Japanese Pharmacopoeia grade. However, the producing area should be taken into consideration to ensure relatively high quality. In addition, planned use and promotion of cultivation must be advocated to avoid confronting Mongolian Glycyrrhiza with the same threat as its congener in China. Our study sheds some light on selecting cultivation areas and superior strains, which are important tasks to promote cultivation.