Current advances in environmental stimuli regulating the glycyrrhizic acid biosynthesis pathway

Glycyrrhizic acid, the main active ingredient of licorice, has good antibacterial, anti-tumor, anti-viral, anti-inflammatory, and immunostimulatory activities. However, the content of glycyrrhizic acid fluctuates greatly in different licorice cultivars, and production depends on plant sources, which greatly limits its development and applications. Therefore, increasing glycyrrhizic acid content has become a research priority. In recent years, regulation of the glycyrrhizic acid biosynthesis pathway has been analyzed, the downstream synthesis pathway in licorice has been fully investigated, some key genes have been cloned, polymorphisms have been studied, and the content of glycyrrhizic acid was shown to be regulated by environmental stimuli. This work has provided a basis for studying the regulation mechanism of the glycyrrhizic acid synthesis pathway. This review summarizes and discusses relevant research to provide a current understanding of the glycyrrhizic acid synthesis pathway and its regulation in licorice.