Clerodane diterpenes lactones, alkaloids, and furan derivatives with hepatoprotective activity isolated from the tuberous root of Paratinospora sagittata (Oliv.) Wei Wang.

Phytochemical studies on the tuberous root of Paratinospora sagittata (Oliv.) Wei Wang led to the isolation of nine previously undescribed compounds (1-5 and 7-10), and an undescribed natural product (6), including two clerodane diterpenoids (1 and 2), six alkaloids (3-8), and two furan derivatives (9 and 10). The structures were characterized by extensive spectroscopic analysis (1D, 2D NMR, and HRESIMS data), together with the comparison of the calculated and experimental electronic circular dichroism (ECD) data and X-ray crystallographic analysis, as well as density functional theory (DFT) calculations of 13C NMR chemical shifts. Among them, two aporphine alkaloids (3 and 4) at 10 μM significantly attenuated acetaminophen (APAP)-induced cytotoxicity in human liver cancer cell line HepG2, with the cell survival rates of 58.85% and 60.14%, respectively.