Isolation of two new prenylated flavonoids from Sinopodophyllum emodi fruit by silica gel column and high-speed counter-current chromatography

•HSCCC were used firstly to purify prenylated flavonoids from Sinopodophyllum emodi.•Two new prenylated flavonoids were isolated from Sinopodophyllum emodi.•The separation procedures proved to be efficient for trace prenylated flavonoids. Two new prenylated flavonoids, sinoflavonoids A–B, were isolated from the dried fruits of Sinopodophyllum emodi by silica gel column chromatography (SGCC) and high-speed counter-current chromatography (HSCCC). The 95% ethanol extract was partitioned with petroleum ether, dichloromethane, ethyl acetate, and n-butanol in water, respectively. The ethyl acetate fraction was pre-separated by SGCC with a petroleum ether–acetone gradient. The eluates containing target compounds were further separated by HSCCC with n-hexane–ethyl acetate–methanol–water (4:6:4:4, v/v). Finally, 17.3mg of sinoflavonoid A and 25.9mg of sinoflavonoid B were obtained from 100mg of the pretreated concentrate. The purities of sinoflavonoid A and sinoflavonoid B were 98.47% and 99.38%, respectively, as determined by HPLC. Their structures were elucidated on the basis of spectroscopic evidences (HR-ESI-MS, 1H-NMR, 13C-NMR, HSQC, HMBC). The separation procedures proved to be efficient, especially for trace prenylated flavonoids.