(±)- Hyppatutions a and B, two pairs of new PPAPs with neuroprotective effect from <i>Hypericum patulum</i> Thunb

Eight polycyclic polyprenylated acylphloroglucinols (PPAPs) which were assigned as two pairs of new optical pure enantiomer, (±)-hyppatutions A [(±)-<b>1</b>] and B [(±)-<b>2</b>] together with four known PPAPs (<b>3-6</b>) were separated from <i>Hypericum patulum</i> Thunb. Their structures, including stereo-chemical structures, were elucidated by NMR spectroscopy analysis, ECD experiments and quantum chemical calculation method. Further, the <i>in vitro</i> neuroprotective effect of all compounds were evaluated by MTT method. All compounds exhibited neuroprotective effect with cell viability ranging from 71.85 ± 0.93% to 95.37 ± 1.29%. Among them, compounds (±)-<b>1</b> exhibited the stronger effect in comparison to the positive control (edaravone, 90.21 ± 0.99%). This research supported the possibilities for the development of new neuroprotective drugs.