Phenolic composition, antioxidant and antimicrobial activity of the extracts from Prunus spinosa L. fruit

Blackthorn (Prunus spinosa L.) is commonly used in food industry and phytotherapy. The contents of phenols, flavonoids, anthocyanins and antioxidative activity in extracts of blackthorn fruit were determined using spectrophotometric methods. The content of total phenol compounds varies from 15.33 to 20.94 mg GAE g-1 of fresh fruit. The content of total flavonoids is very low, and ranges from 0.419 to 1.31 mg QE g-1 of fresh fruits. Anthocyanins content lies between 0.112 mg cyanidin 3-glucoside/g of fresh sample in ethanol extract and 0.265 mg of cyanidin 3-glucoside g-1 of fresh blackthorn fruit in methanol-water 50/50 (v/v) extract. The differences in total phenol compounds content depend on used extraction medium as a consequence of different polarity of used organic solvents and their mixtures, which selectively extract individual compounds. All explored extracts exhibited strong scavenging activity against DPPH radicals, which ranges from 32.05 to 89.10%. Phenolic acids (neochlorogenic and caffeic acids), flavonoids (quercetin and myricetin) and anthocyanins (cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside) were identified in investigated ethanol extracts by HPLC analysis. Ethanol extract shows significant antimicrobial activity against Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Salmonella abony NCTC 6017 and antifungal activity against Candida albicans ATCC 10231. Blackthorn fruit extract exhibits a high phenolic content and a high antioxidant activity, and can be used as an antioxidant in food and pharmaceutical industries.