An EtOAc fraction from the roots of Caragana tangutica Maxim. (CTEA) displayed promising anti-hepatocellular carcinoma (HCC) activity during screening of a traditional Chinese ethnic herb library against HepG2 and Hep3B cell lines. HPLC-based activity profiling of CTEA by combination of MS-guided large-scale semi-preparative HPLC and NMR methods led to the identification of a new pterocarpan glycoside, (-)-maackiain 3-O-6'-O-methyl malonyl-β-d-glucopyranoside (1), together with three known pterocarpan glycosides, (-)-maackiain 3-O-β-d-glucopyranoside (2), 3-O-6'-O-acrylyl-β-d-galactopyranoside (3), and (-)-maackiain 3-O-6'-O-acetyl-β-d-glucopyranoside (4). Compound 1 was isolated during a drug discovery programme aimed at identifying new anti-HCC leads from a natural product library. Anti-HCC study showed that all four compounds exhibited cytotoxic activity with IC50 values range of 29.1-53.5 μg/mL against HepG2 and Hep3B cell lines.
Keywords: Anti-hepatocellular carcinoma; Caragana tangutica; Tibetan medicines; pterocarpan glycosides.