Phenolic compounds of blackthorn (Prunus spinosa L.) and influence of in vitro digestion on their antioxidant capacity

Total phenolic, flavonoid and anthocyanin contents of dichloromethane, ethyl acetate, ethanol, and aqueous extracts of branches, leaves and fruits from Prunus spinosa were quantified by spectrophotometrical methods and the results showed solvent and botanical organ dependence. In order to detect antioxidant activity, a method based on the reduction of DPPH was carried out. Activity of ethanol, ethyl acetate and aqueous extracts of branches demonstrated a higher scavenging capacity compared to other analysed extracts. Phytochemical analysis allowed detecting flavonoids, coumarins, phenolic acids and flavan-3-ols. Ethanolic extract of branches was subjected to an in vitro digestion. Buccal and gastric digestion had no substantial effect on any of the phenolic compounds. However, these compounds were significantly altered during intestinal digestion. The results showed that a significant proportion of these compounds would be transformed into other unknown and/or undetected structural forms. Furthermore, three phenolic acids, two coumarins, fourteen flavan-3-ols, and six flavonols were identified using HPLC-DAD-ESI-MS.