Valorisation of wild cardoon leaf by-product: Extraction, bioactive compounds, antioxidant activity and nanoformulation

Wild cardoon (Cynara cardunculus subsp. cardunculus L.) is an endemic plant of the Mediterranean basin with nutritional and health properties. Herein, fresh wild cardoon leaf by-product was extracted with either a 20:80% v/v EtOH:H₂O or an 80:20% v/v EtOH:H₂O mixture (WCE1 and WCE2, respectively). The quali-quantitative profiles of the two extracts were analysed by LC-ESI-QTOF MS/MS and HPLC-PDA, revealing hydroxycinnamic acids as the predominant phenolic compounds, followed by flavonoids. WCE2, the extract richest in phenolic compounds was incorporated into nanosized enteric polymer-coated liposomes, which exhibited a high entrapment efficiency. The extract's nanoformulation showed antioxidant properties in in vitro cell-free and cell-based models as well as good stability during storage and in both simulated and ex vivo gastrointestinal fluids. Overall, the wild cardoon leaf extract incorporated into polymer-coated liposomes for oral delivery was demonstrated to be a valuable source of antioxidants, thus offering opportunities for their valorisation into functional foods.