Three macrocyclic polyamine alkaloids with a 13-membered ring, named celafurine, celacarfurine, and celabenzine, isolated from Tripterygium wilfordii Hook.f., Celastraceae, were evaluated for their neuroprotective effects in an Alzheimer's disease cell model, which was established by inducing human neuroblastoma SH-SY5Y cells with amyloid beta-peptide (1-42). Celabenzine exhibited remarkable protective effects on SH-SY5Y cells induced by amyloid beta-peptide (1-42) by increasing cell viability from 60 to 80%, and restored the morphology of damaged SH-SY5Y cells. Celabenzine significantly reduced the deposition of amyloid beta-peptide (1-42) in SH-SY5Y cells probably via autophagy through upregulating the level of Beclin-1 and downregulating the level of LC 3-I.