Abstract:
To explore the protective effects and pharmacophore of verbascoside against oxygen-glucose deprivation/reperfusion (OGD/R)-induced neuronal cells injury, we used OGD/R-induced PC12 cells as a neuronal injury model. We investigated the neuroprotective effects of verbascoside and its structural fragments (caffeic acid 3,4-dihydroxyphenethyl ester, caffeic acid, and 3,4-dihydroxyphenylethanol) by MTT and crystal violet staining analysis. Moreover, we studied the protection of verbascoside and its structural fragments on mitochondria by Hoechst33258 staining, JC-1 staining and transmission electron microscope analysis. The neuroprotective mechanisms of verbascoside and its major active fragment caffeic acid were investigated by detecting B cell lymphoma 2 (Bcl 2)/Bcl 2 associated X protein (Bax)-dependent mitochondrial cysteinyl aspartate specific proteinase 3 (caspase 3)/poly ADP-ribose polymerase (PARP) apoptosis pathway by Western blot. The results showed that verbascoside, caffeic acid 3,4-dihydroxyphenethyl ester and caffeic acid significantly improved cell viability and maintained normal PC12 cells morphology. These compounds also significantly reversed OGD/R-induced PC12 cells apoptosis, inhibited cell mitochondria depolarization, and maintained normal mitochondria structure. Furthermore, verbascoside and its major active fragment caffeic acid markedly inhibited the cleavage of mitochondrial apoptotic proteins caspase 3 and PARP, down-regulated Bax, and increased Bcl 2 expression. These results indicate that verbascoside protects OGD/R-induced neuronal cells injury
via mitochondrial caspase 3/PARP apoptosis pathway, and caffeic acid may function as the major pharmacophore structure.