Sesquiterpenoids and their glycosides from Dobinea delavayi (Baill.) Baill.

Eight undescribed sesquiterpenoids, including two eudesmane glycosides dobinosides A and B, five eudesmane aglycones dobinins Q-U, and one germacrane dobinin P, were isolated from the 80% ethanol extract of roots of Dobinea delavayi. Their structures were elucidated by extensive spectroscopic data (1D and 2D NMR, HR-ESI-MS) and single-crystal X-ray diffraction analysis. Dobinoside A, dobinins Q and R, as well as six reported eudesmane sesquiterpenoids, were evaluated for their in vivo antimalarial activities against Plasmodium yoelii BY265RFP in mice. A summary of preliminary structure-activity relationship of eudesmane sesquiterpenoids for in vivo antimalarial activity was described.