Phenolic composition and in vitro cytotoxic activities of total extracts and fractions from Andean potatoes

MORÁN M.; SILVEYRA M.X.; LANTERI M.L.; ANDREU A.B.

Buenos Aires

Encuentro; LXII Reunión Anual de la Sociedad Argentina de Investigación Clínica, Reunión Conjunta de Sociedades de Biociencias; 2017

Varias Sociedades científicas

Andean potatoes (Solanum tuberosum L. ssp. andigena) are a good source of dietary antioxidant polyphenols. We have previously demonstrated that polyphenol extracts from Andean potato tubers exerted a dose-dependent cytotoxic effect in human neuroblastoma SH-SY5Y cells, being skin extracts more potent than flesh ones. This study investigated the phenolic composition and the in vitro cytotoxic activities of total extracts and fractions of skin and flesh tubers of three Andean potato varieties (Santa María, Waicha and Moradita). Potato total extracts were subjected to liquid-liquid fractionation using the solvent ethyl acetate in organic and aqueous fractions. Both fractions were analyzed by DAD-HPLC and results corroborated the expected composition of each fraction. Organic fractions were rich in phenolic acids (chlorogenic acid the most abundant one) and aqueous fractions contained mainly anthocyanins (except in non-pigmented Waicha and Moradita fleshes). The major anthocyanidins present in red tissues (Santa María skin and flesh, and Waicha skin) were pelargonidin and peonidin, while in Moradita purple skin petunidin and malvidin were the major ones. Fractions containing phenolic acids did not result cytotoxic against SH-SY5Y cells, and indeed some of them increase cellular metabolism compared to controls. Aqueous fractions were cytotoxic and even more potent than their respective total extracts. Treatment with a combination of both fractions showed similar cytotoxic response to the corresponding extract. Since some of the bioactive aqueous fractions lack pigmentation (Waicha and Moradita fleshes) it is tempting to speculate that anthocyanins are not direct responsible and that other compounds, unidentified yet, play a crucial role in inducing cell death. Findings indicate that the activity of Andean potato extracts is a combination of various compounds and contribute to the revalorization of potato as a functional food. Keywords: cytotoxicity; phenolic compound; Solanum tuberosum L.