In-Depth LC-ESI/HRMS-Guided Phytochemical Analysis and Antioxidant Activity Analysis of Eco-Sustainable Extracts of Cynara cardunculus (Carciofo di Paestum PGI) Leaves

The Italian Carciofo di Paestum (<i>C. scolymus</i>) PGI, an artichoke variety from the Campania region, was investigated for its potential to reuse by-products for food supplements. EtOH:H₂O 50:50 and 75:25 extracts of its leaves were analyzed for phenolic and flavonoid content and antioxidant activity (TEAC: 1.90 and 1.81 mM of Trolox; DPPH IC₅₀: 106.31 µg/mL and 128.21 µg/mL; FRAP: 1.68 and 1.58 mM FeSO₄/g extract). To further investigate the antioxidant potential, the ability of the two extracts to scavenge reactive species was assessed in Caco-2 cell cultures, showing a dose-dependent antioxidant capacity. To highlight metabolites responsible for the activity, LC-ESI/HRMSMS analysis was achieved, revealing 28 compounds (sesquiterpenes, megastigmanes, quinic acid and hydroxycinnamic acid derivatives, flavonoids, lignans, triterpenoid saponins, and polar fatty acids), of which structures were determined using 1D- and 2D-NMR analysis. In addition, quantitative determination of caffeoyl, dicaffeoyl, and quinic acid derivatives (CQAs) was performed through LC-ESI/QTrap/MS/MS, highlighting that the most abundant compound was 5-caffeoylquinic acid (<b>6</b>), with values of 9.310 and 7.603 mg/g extract in EtOH:H₂O (75:25) and EtOH:H₂O (50:50), respectively. The analysis showed that extracts were rich in bioactive compounds, suggesting their potential for development into antioxidant-based food supplements that may protect cells from oxidative stress and support overall wellness.