Megastigmane glycosides from Heterosmilax yunnanensis and their neuroprotective activity

Ten previously undescribed megastigmane glycosides (1-5, 8-12) and four known compounds (6-7, 13-14) were isolated from the roots of Heterosmilax yunnanensis Gagnep. Their planar structures were determined by NMR, HRESIMS, UV and IR spectroscopic data. The absolute configurations were established through Rh₂(OCOCF₃)₄-induced ECD, quantum computational chemistry, experimental ECD and ¹³C chemical shift. The neuroprotective activity of the compounds was assessed in H₂O₂-induced PC12 cell model. Compounds 3 and 6-10 exhibited good neuroprotective activity compared to the positive control edaravone.