School of Traditional Chinese Materia Medica, Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, People's Republic of China; Chinese People's Liberation Army 210 Hospital, Dalian 116021, People's Republic of China. Electronic address: [Email]
Five pairs of enantiomeric 8-O-4' neolignans (1a/1b-5a/5b), including seven new compounds (1a/1b, 2a, 3a, 4a/4b and 5b), were obtained from the fruits of Crataegus pinnatifida Bge. Their structures were determined by comprehensive spectroscopic analyses. The absolute configurations of the enantiomers were determined by comparison of the experimental ECD with the calculated data. Additionally, all the enantiomeric neolignans were evaluated for their neuroprotective activity against H2O2-induced cell injury in human neuroblastoma SH-SY5Y cells, and most of them showed potent selective neuroprotective activity. Especially, 3b (72.98%) showed the best protective effect, better than 3a (63.49%) and trolox (62.86%) at 25 μM.