Pinus pinea L. Periderm as a Sustainable Source of Phenolic Bioactives: Integrated Phytochemical, Antioxidant, and...

Pinus pinea L. is a widespread Mediterranean conifer whose bark-derived tissues remain poorly investigated as potential sources of bioactive secondary metabolites. In this study, a hydroalcoholic crude extract of the periderm, an outer renewable bark layer compatible with sustainable collection, was evaluated as an underexplored natural matrix. HPLC-DAD identified taxifolin as the main quantified marker compound, corresponding to 21.1 mg/g of dry extract. Untargeted UPLC-QTOF-MS analysis revealed a polyphenol-rich profile, mainly represented by condensed tannins and flavonoids in ESI(-) mode, while terpenoids were more evident in ESI(+) mode. The extract showed concentration-dependent DPPH radical-scavenging activity, with an IC₅₀ of 12.31 µg/mL, comparable to ascorbic acid. Comparison with taxifolin tested at concentrations equivalent to those estimated in the extract indicated that taxifolin accounted for only part of the observed antioxidant response. In SH-SY5Y cells, the extract was cytocompatible up to 1 µg/mL and partially counteracted H₂O₂-induced reduction in cell viability within this non-cytotoxic range. TXRF analysis provided a preliminary safety-oriented elemental profile, with regulated elements detected at low levels. Overall, these findings support P. pinea periderm as a renewable Mediterranean source of secondary metabolites with antioxidant potential, while further mechanistic and toxicological studies are required to confirm its functional applicability.