Abstract
Vlasoulides A and B (1 and 2), a pair of epimeric C(32) sesquiterpene lactone dimers, featuring a 5/7/5/5/(5)/7 ring system were isolated from the roots of Vladimiria souliei. Their chemical structures were determined by comprehensive analysis of spectroscopic data, including HRESIMS and 1D and 2D NMR spectroscopic data. Their absolute configurations were established by Mosher's method and ECD experiments. Furthermore, biological studies showed that compound 1 showed prominent neuroprotective effects against glutamate-induced neurotoxicity in PC-12 cells, with EC(50) values of 13.54 ± 0.33 μM, while, the EC(50) value of compound 2 is greater than 30 μM.