Phenolic profile and biological potential of wild blackberry (Rubus discolor) fruits

Abstract

The berries of Rubus discolor are considered a rich source of phytochemicals which could play an important role in the prevention of prevalent contemporary chronic diseases. Thus, the goal of the presented study was to determine the profile of phenolic acids and anthocyanins of aqueous and ethanol extracts of R. discolor fruit, and their free radical scavenging, antiproliferative, antidiabetic and antimicrobial activities. LC-MS/MS analyses confirmed the presence of 11 phenolic acids with protocatechuic and gallic acids being the major compounds. Additionally, cyanidin- glucoside/galactoside was the most abundant among the five identified anthocyanins. The ethanol extract was more efficient in scavenging free radicals than the aqueous extract. The absence of antiproliferative activity was observed for both extracts. However, they inhibited carbohydrate hydrolysing digestive enzymes associated with type-2 diabetes. Furthermore, the obtained results for α-glucosidase inhibitory activity (IC50 values 44.52 and 80.72 μg/mL, for the aqueous and ethanol extracts, respectively) indicate significantly higher activity than the positive control, GlucobayR (233.38 μg/mL). The ethanol extract was more effective against all of the examined bacteria (Bacillus cereus, Staphylococcus aureus and Enterobacter cloacae) than the aqueous extract. On the contrary, the aqueous extract showed better antifungal properties, particularly against Trihoderma viride and Penicillium verrucosum var. cyclopium. The quantified phenolics and presented bioactivities of R. discolor fruit extracts candidate them as a potential source of bioactive compounds which might be used in the food, pharmacy and cosmetic industries.