Six Undescribed Dibenzocyclooctadiene Lignans With Neuroprotective Effects From Kadsura coccinea Roots

Phytochemical investigation of the roots of Kadsura coccinea led to the isolation of eleven dibenzocyclooctadiene lignans (1-11), including six new compounds (1-6). Their structures were established by HRESIMS, NMR, and ECD analyses. All isolates were evaluated for neuroprotective effects against 6-hydroxydopamine-induced injury in PC12 cells. Compounds 2 and 10 showed the most potent activities, increasing cell viability by 20.54% and 30.67%, respectively, at 50 µM. Mechanistic studies indicated that both compounds reduced intracellular ROS accumulation and enhanced SOD activity, while compound 10 further activated the Nrf2/HO-1 signaling pathway. These findings suggest that dibenzocyclooctadiene lignans from K. coccinea are promising neuroprotective agents against oxidative stress-induced neuronal injury.