Monoterpenoids from the roots of Paeonia lactiflora Pall. and their neuroprotective activity

Three novel monoterpenoids (1-3), together with nine known ones (4-12), were isolated from the roots of Paeonia lactiflora Pall. The newly discovered monoterpenoids were structurally characterised by detailed spectroscopic analysis. Furthermore, all isolated monoterpenoids were evaluated for their neuroprotective activity against H₂O₂-induced injury in PC12 cells in vitro. Most of the monoterpenoids demonstrated significant neuroprotective effects, with EC₅₀ values ranging from 3.12 ± 0.12 to 35.76 ± 0.28 μM. Finally, molecular docking of compounds 1 and 2 with Nrf2 was carried out, and favourable binding interactions were observed.