LAUSR

Five new phthalide dimers, chaxiongnolides C-G (1-5), the two enantiomers of riligustilide (6a and 6b) and tokinolide B (7) were isolated from the aerial parts of Ligusticum sinense Oliv cv. Chaxiong. The structures of 1-5 were elucidated through extensive spectroscopic analysis, and the relative configurations of compounds 2 and 3 were further confirmed by an X-ray diffraction experiment. The absolute configurations of 1-3 were assigned by comparing calculated and experimental ECD spectra. The ECD exciton chirality method was used to confirm the absolute configurations of compounds 4, 5, 6a and 6b. Compounds 1-3 are the first dimeric phthalides to be reported that are comprising a sedanolide unit. The compounds were evaluated in vitro for their cytotoxic activity against select human cell lines.