Comparative Evaluation of Green Extraction Technologies for Phenolic Compounds from Algerian Blackthorn (Prunus spinosa L.): Antioxidant, Antimicrobial, and Phytochemical Insights

Blackthorn (<i>Prunus spinosa</i> L.) is an underutilized Mediterranean wild fruit recognized as a valuable source of bioactive phenolic compounds with potential applications in food and nutraceutical formulations. Despite growing interest in sustainable extraction approaches, systematic comparisons of green extraction technologies for blackthorn phenolic recovery remain limited, particularly for North African ecotypes. In this study, four non-conventional green extraction techniques, pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, and Ultra-Turrax-assisted extraction, were compared for the recovery of phenolic compounds from Algerian blackthorn fruits under method-specific controlled conditions. Total phenolic compounds, flavonoids, anthocyanins, and condensed tannins were quantified, together with antioxidant capacity evaluated using multiple complementary assays. Pressurized liquid extraction yielded the highest total phenolic compound content (21.89 mg gallic acid equivalents/g dry weight) and flavonoid content (8.18 mg catechin equivalents/g dry weight), while microwave-assisted extraction showed the highest anthocyanin recovery (3.19 mg cyanidin-3-glucoside equivalents/g dry weight). Antioxidant capacity values obtained by different assays showed comparable trends for pressurized liquid extraction and microwave-assisted extraction. The extract obtained by the most effective method was further evaluated for antimicrobial activity, showing selective inhibitory effects against methicillin-resistant <i>Staphylococcus aureus</i>, <i>Acinetobacter baumannii</i>, and <i>Bacillus subtilis</i>. Chemical characterization by liquid chromatography-tandem mass spectrometry revealed a profile dominated by flavonoids, mainly quercetin derivatives, and hydroxycinnamic acids. Overall, these findings highlight pressurized liquid extraction as a promising green technology for the valorization of blackthorn fruits as sources of phenolic compounds for food-related applications.