Chiral resolution and neuroprotective activities of enantiomeric dihydrobenzofuran neolignans from the fruit of Crataegus pinnatifida

Abstract

Three pairs of enantiomeric dihydrobenzofuran neolignans (1a/1b-3a/3b) including four new compounds (1a/1b and 2a/2b) were isolated from the fruit of Crataegus pinnatifida. Their structures including the absolute configurations were elucidated by extensive spectroscopic analyses and comparison between the experimental measurements of electronic circular dichroism (ECD) and the calculated ECD spectra. Additionally, all the enantiomeric neolignans were investigated for their neuroprotective activities against H2O2-induced cell injury in human neuroblastoma SH-SY5Y cells. It was found that enantiomers 1a and 1b displayed different degrees of neuroprotective activities, and the results showed enantioselectivity, in which that 1b exhibited noticeable neuroprotective activity, while its enantiomer 1a only exhibited obvious protective effect at lower concentration. Further study demonstrated that the potential protective activities of compounds appeared to be mediated via suppressing cell apoptosis.