A total of 12 megastigmane glycosides (1 - 12), including four undescribed ones, were extracted from the leaf tissues of Nicotiana tabacum. The molecular frameworks of all isolates could be indicated by 1D and 2D-NMR analysis and mass spectrometry along with comparison with those previously reported. Absolute configuration from four new metabolites (1 - 4) was established through ECD and empirical rules of 13C-NMR chemical shift. Additionally, a hydrogen peroxide-induced SH-SY5Y cell model was used to assess the isolates' in vitro neuroprotective activity, and the bioassay results demonstrated compounds 2, 3, 6, and 7 displayed moderate protective effects against H2O2-induced neurotoxicity at 10 μM in comparison to the positive control, edaravone.
Keywords: Megastigmane glycosides; Nicotiana tabacum; absolute configuration neuroprotective activity; structural elucidation.