Polyphenol composition and in vitro antiproliferative effect of corm, tepal and leaf from Crocus sativus L. on human colon adenocarcinoma cells (Caco-2)

• Glycosides of kaempferol, luteolin and quercetin in tepals and leaves of saffron were studied.
• Proliferation of Caco-2 cells was greatly inhibited by tepal and leaf extracts.
• Corm saffron extract caused toxicity and abolished proliferation of Caco-2 cells.
• Saffron's corms, tepals and leaves are potential sources of anticancer molecules.

Saffron is cultivated for production of the saffron spice. Nevertheless, a huge amount of saffron by-products including corms, tepals and leaves with little or no commercial value are generated during the processing of the spice. This biomass contains bioactive compounds whose exploitation can increase the profitability and sustainability of this traditional crop. A significant amount of polyphenols, mainly glycosides of kaempferol, luteolin and quercetin, have been determined in tepals and leaves of saffron. Proliferation of Caco-2 cells was greatly inhibited by the tepal and leaf extracts (ED50 0.42 mg/ml), while the corm extract caused some signs of toxicity and completely abolished proliferation (ED50 0.05 mg/ml). To our knowledge, these are the first data reporting the inhibition of the proliferation of Caco-2 cells by extracts from tepals and leaves of saffron, and polyphenols could be responsible for this effect.