Flos Sophorae Immaturus: Phytochemistry, bioactivities, and its potential applications

Flos Sophorae Immaturus (FSI) is a dried flower bud derived from Sophora japonica L. FSI contains various phytochemicals, including rutin, quercetin, kaempferol, isorhamnetin, genistein, and Flos Sophorae saponins. The active components of FSI have anti-cancer, antithrombotic, analgesic, antibacterial, antiviral, anti-aging, anti-inflammatory, anti-allergic, and antioxidant remarkable pharmacological and nutritional properties. There is a growing interest in developing FSI both as a functional food and a health product, as well as its use in other applications including dyes and cosmetics. However, the lack of systematic information on the composition of FSI and its specific health effects has greatly hindered its application as sustainable, functional plant material. Herein, we reviewed the currently available research on the nutritional components and biological characteristics of FSI and described the relationship between FSI-derived polyphenols and their biological activities in vitro and in vivo. This review systematically summarizes the medicinal and edible uses of FSI and proposes directions for future research, which will provide a theoretical basis for the utilization of FSI as a health supplement, functional food product, and natural pigment raw material in the future.