Chemical characterization of polyphenol extracts from Andean and industrial Solanum tuberosum tubers and their cytotoxic activity on human hepatocarcinoma cells

Abstract

Background: Polyphenols are plant metabolites that have been largely studied for their beneficial effect on human health. Potato is one of the most important crops worldwide and is a relevant source of human dietary nutrients and antioxidants. Particularly, pigmented potatoes contain the highest levels of polyphenolic compounds. Hepatocellular carcinoma is one of the most frequent types of cancers worldwide and despite the existence of treatments; it is yet associated with a high mortality rate. Thus, new drugs are needed, and polyphenols are a potential source of anti-hepatocellular carcinoma compounds. The objectives of this study were to determine the content of different groups of polyphenols (phenolic acids, anthocyanins and flavan-3-ols) in five potato polyphenolic extracts, and to study their antioxidant and cytotoxic activities on a human hepatocellular carcinoma cell line. Methods: four Andean varieties and one industrial potato variety were selected for this study. Polyphenolic quantification and composition were determined by spectrophotometric assays and HPLC-DAD analysis. The antioxidant and cytotoxic activities were evaluated through DPPH and MTS assays respectively. Results showed that pigmented varieties possessed higher levels of the analyzed phenolic compounds. HPLC analysis showed that chlorogenic acid was the main phenolic acid in all the potato polyphenolic extracts. Also, pigmented potatoes presented higher levels of antioxidant activity compared to non-pigmented ones, showing a positive correlation with the total phenolic content. Finally, treatment with three of the studied potato polyphenolic extracts reduced the viability of Hep3B. Furthermore, one extract from a non-pigmented variety affected cell viability to a similar extent as extracts from pigmented potatoes, suggesting that other compounds, besides anthocyanins, may be responsible of the cytotoxic effect of this polyphenolic extracts. Conclusion: These results suggested that polyphenolic compounds present in the Andean potato varieties could be used as a potential source of anti-hepatocarcinoma drugs.