Enantiomeric neolignans from Ficus erecta and their neuroprotective activities against 6-OHDA-induced oxidative...

Nine pairs of enantiomeric neolignans (1a/b - 9a/b), including seventeen previously undescribed compounds (1a/b-5a/b, 6a, 7a/b-9a/b), were isolated from the whole plant of Ficus erecta. Their planar structures were elucidated via comprehensive spectroscopic analyses, while the absolute configurations were determined by comparison of experimental ECD spectra with calculated data. 1a/b and 5a/b-7a/b exhibited moderate antiproliferative effects against HepG2, A549, and HCT116 cancer cell lines, while 4a/b, 8a/b and 9a/b demonstrated neuroprotection in a 6-OHDA-induced oxidative stress model using PC12 cells. Notably, 4a/b and 9a/b attenuated oxidative damage in a dose-dependent manner (6.25-25 μM), suppressing ROS and MDA levels while elevating SOD and GSH levels. Mechanistically, Western blot analysis showed that 4a/b upregulated nuclear Nrf2 and cytoplasmic HO-1, suggesting Nrf2/HO-1 pathway activation contributes to their neuroprotective effects.