Lignans and neolignans with isovaleroyloxy moiety from Solanum lyratum Thunb.: Chiral resolution, configurational assignment and neuroprotective effects

Eight pairs of enantiomeric lignans and neolignans including thirteen undescribed compounds, along with an undescribed meso compound, were isolated from the herbs of Solanum lyratum Thunb.(Solanaceae). Their structures and relative configurations were determined by extensive spectroscopic analyses of HRESIMS and nuclear magnetic resonance. The absolute configurations of the pure isomers were established based on the cooperative comparison between the experimental and calculated electronic circular dichroism (ECD) and optical rotation (OR). It is interesting that we obtained several naturally occurring stereoisomers with the identical gross structure possessing several stereogenic carbons from S. lyratum. Additionally, all isolates were assessed for neuroprotective effects toward human neuroblastoma SH-SY5Y cells injury induced by H₂O₂.

Keywords: Chiral resolution; Enantiomers; Neuroprotective effects; Solanaceae; Solanum lyratum Thunb..