Eight polycyclic polyprenylated acylphloroglucinols (PPAPs) which were assigned as two pairs of new optical pure enantiomer, (±)-hyppatutions A (±)-1 and B (±)-2 together with four known PPAPs (3-6) were separated from Hypericum patulum Thunb. Their structures, including stereo-chemical structures, were elucidated by NMR spectroscopy analysis, ECD experiments and quantum chemical calculation method. Further, the in vitro 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 (±)-1 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.
Du et al. (Thu,) studied this question.