New Findings in Prunus padus L. Fruits as a Source of Natural Compounds: Characterization of Metabolite Profiles and Preliminary Evaluation of Antioxidant Activity

European bird cherry (Prunus padus L.) has been known since the Middle Ages for its medical/food use and high health-promoting value. This study aimed to assess the potential of these fruits as a source of bioactive compounds through the characterization of its physicochemical traits, nutraceutical properties, phytochemical composition via HPLC fingerprint, and antioxidant capacity. Fully ripened fruits of Prunus padus L. (Colorata cv) were collected in mid-July 2017 in Chieri, north-western Italy. The TPC (194.22 ± 32.83 mg(GAE)/100 g(FW)) and TAC (147.42 ± 0.58 mg(C3G)/100 g(FW)) values were obtained from the analyzed extracts. The most important phytochemical class was organic acids (48.62 ± 2.31%), followed by polyphenols (35.34 ± 1.80%), monoterpenes (9.36 ± 0.64%), and vitamin C (6.68 ± 0.22%). In this research the most important flavonols selected as marker were quercitrin (16.37 ± 3.51 mg/100 g(FW)) and quercetin (11.86 ± 2.36 mg/100 g(FW)). Data were reported based on fresh weight. Moreover, fresh fruits showed a mean antioxidant activity value of 17.78 ± 0.84 mmol Fe(2+)·kg(−1). Even though the seeds and leaves contain cyanogenic glycosides, this study showed that these fruits could be a natural source of bioactive compounds with high antioxidant properties, due to the contents of organic and phenolic acids, catechins, and a synergetic effect of vitamin C and flavonoids.