Effects of manganese on accumulation of Glycyrrhizic acid based on material ingredients distribution of Glycyrrhiza uralensis

Abstract Wild and cultivated Licorice ( Glycyrrhiza uralensis FISCH.) are the main source of licorice. In recent years, wild Glycyrrhiza plants have been seriously damaged and this has reduced the population. The cultivation of Licorice has been the best way to solve the problem of its shortage. The contents of glycyrrhizic acid greatly differs in licorices cultivated at different region of China. However, the contents of glycyrrhizic acid in cultivated licorice in china is lower than that of wild licorice. To produce the high quality cultivated licorices, researchers studied the factors affecting the glycyrrhizic acid produced in licorice. It was found that manganese (Mn) application improved the medicinal material yieldand quality especially the contents of the glycyrrhizic acid. In this paper, we investigated the effects of Mn on the accumulation of glycyrrhizic acid in medicinal materials based on the material ingredients distribution and also explored the mechanism. The influence of Mn on the relative contents of glycyrrhizic acid were significant except for day 30 while the influence is significant to the absolute contents all the time. The relative contents of glycyrrhizic acid increased while the contents of crude protein, crude fiber and total material ingredients decreased. The absolute contents of glycyrrhizic acid rose when crude protein contents increased. This implies that the contents of glycyrrhizic acid are in a close relationship with material ingredients. Mn application of appropriate concentration could stimulate the formation of primary metabolites, and then promote the secondary metabolism of G. uralensis which could lead to the formation and accumulation of glycyrrhizic acid in G. uralensis .