Valorization of Globe Artichoke (Cynara scolymus) Agro-Industrial Discards, Obtaining an Extract with a Selective Effect on Viability of Cancer Cell Lines

Abstract

Globe artichoke (Cynara scolymus L.) is considered one of the most significant sources of phenolic antioxidants in nature. However, more than 60% of its total volume is discarded for consumption purposes, making available an abundant, inexpensive and profitable source of natural antioxidants in the discarded fractions. Polyphenolic antioxidants from a South American variety of artichoke agro-industrial discards (external bracts and stems) were obtained by mild extraction processes. Best results were achieved at 40 °C, 75% of ethanol and 10 min of reaction, obtaining 2.16 g gallic acid equivalent (GAE)/100 g of total phenolic compounds (TPC) and 55,472.34 µmol Trolox equivalent (TE)/100 g of antioxidant capacity (oxygen radical absorbance capacity (ORAC)). High-performance liquid chromatography (HPLC) analyses determined that caffeoylquinic acids comprise up to 85% of the total polyphenolic content, and only around 5% are flavonoids. Inulin content in the artichokes residues was recovered (48.4% dry weight (dw)), resulting in an extract with 28% of inulin in addition to the aforementioned antioxidant capacity. The artichoke discard extract in a concentration of 500 mg/L produced a strong decrease in Caco-2 and MCF-7 cancer cell lines viability, whereas healthy fibroblasts maintained their viability when the extract was concentrated at 1500 mg/L. These results suggest that the artichoke extract presents a good anti-proliferative potential effect on Caco-2 and MCF-7 cells.