Two new asymmetric sesquiterpene dimers from the rhizomes of Ligularia muliensis.

Two new asymmetric eremophilane-type sesquiterpene dimers, ligulamulienin A (1) and B (2), were isolated from the rhizomes of Ligularia muliensis. Their structures were determined based on their spectroscopic data, including IR, EI-MS, HR-electrospray ionization (ESI)-MS, 1D and 2D-NMR spectroscopy. The cytotoxicity of compounds 1 and 2 was measured in in vitro human carcinoma (MGC-803), human hepatoma (HEP-G2), and murine sarcoma (S-180) cell lines.