Four pairs of neolignan enantiomers with distinctive isochroman moiety from the fruits of Crataegus pinnatifida and their protective activities against H2O2-induced SH-SY5Y cells

Four pairs of neolignan enantiomers (±)-1− (±)-4 with a distinctive isochroman moiety, including seven undescribed compounds, were isolated and identified from the fruits of Crataegus pinnatifida. Structural characterization of these compounds was established through comprehensive spectroscopic analyses, as well as quantum chemical calculations of ECD and NMR data. The preliminary bioassay displayed that compounds (+)-2 and (±)-3 exerted protective activities against H2O2-induced human neuroblastoma SH-SY5Y cells compared with the positive control. These bioactive compounds could be potential candidates for further pharmaceutical applications. Four pairs of neolignan enantiomers with a distinctive isochroman moiety, including seven undescribed compounds (±)-1− (±)-3 and (−)-4, were isolated from Crataegus pinnatifida. Some of them exerted potential protective activities against H2O2-induced SH-SY5Y cells. [Display omitted] •Four pairs of neolignan enantiomers were isolated from Crataegus pinnatifida.•All isolates were separated by chiral resolution.•All isolates possess a distinctive isochroman unit.•(+)-2 and (±)-3 exerted protective activity against H2O2-induced SH-SY5Y cells.