Phenolic Composition, Antioxidant, Anti-Enzymatic, Antimicrobial and Prebiotic Properties of Prunus spinosa L. Fruits

Blackthorn (Prunus spinosa L.) fruit is bluish-black wild fruit traditionally used in nutrition and medicine. It is recently gaining attention as a functional food and an underutilized source of bioactive compounds for application in the food and pharmaceutical industry. This study aimed to assess the health-promoting potential of blackthorn fruits from Serbia by examining their chemical composition and in vitro biological activities. Phytochemical analysis of the blackthorn fruit extracts was performed using LC-DAD-ESI-MS. The total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC) content, antioxidant capacity, and enzyme inhibitory activities were determined spectrophotometrically. The antimicrobial and prebiotic properties were tested using the broth microdilution method. Twenty-seven phenolics belonging to the classes of hydroxybenzoic and hydroxycinnamic acids derivatives, flavonoids, and anthocyanins were identified, with caffeoylquinic acid as the most abundant compound. Blackthorn extracts were characterized by notable TPCs, TFCs, and TACs, and free radical scavenging and reducing ability. The enzyme inhibitory effects (IC50 = 0.43-2.16 mg/mL) were observed towards alpha-amylase, alpha-glucosidase, acetylcholinesterase, and tyrosinase. Blackthorn fruit extracts in a concentration-dependent manner (0.3-5 mg/mL) stimulated the growth of several probiotic microorganisms and their mixtures, especially the yeast Saccharomyces boulardii. Obtained results support further evaluation of the functional food potential of blackthorn fruit.