New dihydrohomoisoflavones from Polygonatum sibiricum with neuroprotective activity

Six new dihydroisoflavones (1-6) along with eight congeners (7-9, 11-15) as well as a known chalcone derivative (10) were isolated from Polygonatum sibiricum. To enhance the specificity and efficiency of the separation process, a combination of MSDIAL and MassQL techniques was used alongside column chromatography with silica gel, ODS, and preparative HPLC. The structural elucidation of the compounds was accomplished via thorough spectral characterisation, encompassing techniques such as 1D and 2D NMR, HR-ESI-MS, IR, UV and ECD. These findings were further validated by comparing them with data from existing literature. Furthermore, the neuroprotective activity of all purified compounds was assessed using a PC12 cell model subjected to H₂O₂ induction. The results of our study indicated that compounds 2, 3, 5, 11, and 12 significantly alleviated H₂O₂-induced damage in PC12 cells, increasing cell viability to approximately 74%, 76%, 79%, 76%, and 72%, respectively, at 50 μM without exhibiting cytotoxicity.