CONICET | Buscador de Institutos y Recursos Humanos

Andean potatoes (Solanum tuberosum L. ssp. andigena) are a good source of dietary polyphenols, such as chlorogenic acid and anthocyanins. We have previously demonstrated that polyphenol extracts from Andean potato tubers exerted a concentration-dependent cytotoxic effect in human neuroblastoma SH-SY5Y cells. The aim of this study was to investigate the mechanisms involved in the cytotoxic activity induced by flesh tuber´s polyphenols from Andean potato cultivar Santa María. In order to test the anti-neuroblastoma mechanisms, we assayed the CC50 (50% cytotoxic concentration) of total polyphenols extract on SH-SY5Y cells. First, we observed that polyphenols induced changes in the cells morphology, which acquired a rounded shape with a decrease in the neurites extent. After 24 h of treatment with polyphenols, apoptosis was found in 57.8% of the cell population, being the 30% of them positive for propidium iodide, which indicated impairment in the integrity of the plasmatic membrane. We also analyzed the effect of polyphenols on the cell cycle distribution using flow cytometry. We detected increase of cells in G2 phase after 24 h of polyphenols treatment, but a major change in the cell cycle was found at longer period of incubation. The results showed an increase of 14.5% in both G2 and S phases, while decreased the number of cells in G1 phase. In addition, an increase of 4.08% of cells in sub-G1 phase was detected after the polyphenols treatment, which is typical to happen when the apoptosis takes place. Finally, we performed the cell nuclei staining with DAPI in order to check the integrity of the genomic DNA, observing significant alterations such as bright nuclear condensation and in some cases fragmented nucleus. These findings demonstrated that polyphenols from flesh tuber´s Andean potato cultivar Santa María would be a good source of bioactive compounds with some impact in human health.