RESUMO
The Aß peptide-mediated toxicity participates in the neuronal death that occurs in Alzheimer's disease. The present study aims to isolate the major compounds of Serjania erecta Radlk leaves and assess whether these compounds protect PC12 cells from Aß25-35 peptide-induced toxicity. We isolated three flavonoid glycosides with high purity: quercetrin, vitexin, and isovitexin. The Aß25-35 peptide alone decreased the PC12 cell viability in a concentration-dependent manner, as evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay. We selected the Aß25-35 peptide concentration of 50 µM for the experiments. Treatment of PC12 cells with the flavonoids before exposure to the Aß25-35 peptide increased cell viability, i.e., these compounds protected the cells against Aß25-35 peptide-induced toxicity. Vitexin promoted higher protection levels than quercetrin and isovitexin, and reduced the lactate dehydrogenase release and NO production in Aß25-35 peptide-treated PC12 cells. Therefore, the glycosylated flavonoids that exist in S. erecta leaves, especially vitexin, protect PC12 cells from Aß25-35 peptide-induced toxicity.
