Kaempferol

The dried roots of S. baicalensis as identified by the authors were purchased from the Pharmacy of Chengdu Tongrentang (Sichuan, China). And the dried flowers and buds of S. japonica were purchased from the Lotus Pond Chinese herbal medicine market (Sichuan, China). The reference substances of acacetin, baicalin, wogonin, baicalein, beta-sitosterol, kaempferol, and quercetin were purchased from the Sichuan Weikeqi Biological Technology Co., Ltd (Sichuan, China). SQP electronic balance Sartorius was purchased from Sartorius Scientific Instruments (Beijing) Co., Ltd., TGL-16G high-speed centrifuge was purchased from Shanghai Anting Scientific Instrument Factory, electronic analysis balance BS-6KH was purchased from Shanghai Yousheng Weighing Apparatus Co., Ltd., DZTW thermostat (the electric heating jacket) was purchased from Beijing Yongguangming Medical Instrument Co., Ltd., and the SHZ-D(III) circulating water vacuum pump was from Zhengzhou Du Fu Instrument Factory and Waters 2695 high-performance liquid chromatography from the United States.