<i>Cornus mas</i> L. Seeds as a Potent Natural Antioxidant Source: Insights from Phenolic Profiling and Antioxidant Capacity Assays

In this study, the antioxidant potential and phenolic compound profiles of extracts obtained from the fruit, leaf, and seed parts of Cornus mas L. (cornelian cherry) collected from Tortum, Erzurum (Turkey) using ethanol and water solvents were evaluated. Antioxidant capacity was determined by DPPH, ABTS, and CUPRAC assays, while total phenolic content (TPC) and flavonoid content were measured spectrophotometrically. In addition, phenolic profiles were analyzed using LC-MS/MS technique. Among the extracts, those labeled "SD-MAS-H₂O" and "SD-MAS-EtOH" exhibited the highest antioxidant activities, with IC₅₀ values of 2.16±0.11 and 2.27±0.09 µg/mL for DPPH, and 1.35 and 1.47±0.05 µg/mL for ABTS, respectively. In the CUPRAC assay, these same extracts showed the strongest reducing power, with absorbance values of 0.866 and 0.828. The highest total phenolic content was found in the "SD-MAS-ETOH" extract (157.80 µg GAE/g), followed by "LF-MAS-ETOH" (113.09 µg GAE/g) and "SD-HDR" (110.76 µg GAE/g). The "SD-MAS-ETOH" extract also contained the highest total flavonoid content (586.47 µg QE/g). LC-MS/MS analysis revealed that the "SD-MAS-H₂O" extract contained high concentrations of gallic acid (443.62 mg/L), vanillic acid (484.35 mg/L), hydroxybenzaldehyde (250.52 mg/L), and hesperidin (34.74 mg/L). These compounds are considered major contributors to the observed antioxidant activity. Pearson correlation analysis showed significant negative correlations between total phenolic content and IC₅₀ values for DPPH (r = -0.7535) and ABTS (r = -0.7353), indicating a strong relationship between phenolic composition and antioxidant capacity. These findings highlight the potential of Cornus mas L. as a valuable natural antioxidant source for applications in functional foods and pharmaceutical products.