Eight sesquiterpenoids including costunolide (1), parthenolide (2), 11α,13‐dihydroparthenolide (3), 9β‐hydroxy‐dihydroparthenolide (4), (‐)‐bisparthenolidine (5), 11α,13‐dihydro‐β‐cyclocostunolide (6), α‐cadinol (7), magnograndiolide (8) were isolated from the barks and roots of Michelia alba. The structures of these compounds were elucidated by spectroscopic methods (MS, 1D and 2D NMR) and comparison with the reported data. Compounds 5‐8 have been isolated for the first time from Michelia alba.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of whole Crinum asiaticum var. sinicum plants resulted in the isolation of seven alkaloids (1–7), including one new compound (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of 1 was established by ECD. A molecular docking and molecular dynamics simulation was carried out for the isolated compounds to screen for acetylcholine (AChE) inhibitory activity. The target compounds were evaluated for their inhibitory effects on AChE activity in vitro. The results suggest that these C. asiaticum alkaloids possess the ability to treat Alzheimer’s disease.