Olea europaea bud extracts: inhibitory effects on pancreatic lipase and α-amylase activities of different cultivars from Calabria region (Italy)

Plants have always represented a great resource of bioactive compounds. Olea europaea is considered one the most important fruit trees of the entire Mediterranean basin and its use in traditional medicine dates back to very ancient times. In this work, bud extracts from two O. europaea cultivars, ‘Carolea’ and ‘Cassanese’, were investigated in order to evaluate their phytochemical profile and biological activities. Each sample was extracted with a hydroalcoholic solution with two different extraction techniques: classical maceration and extraction by Naviglio Extractor®. Total phenolic and flavonoid content was assessed, and the apolar constituents were detected by means of GC-MS. In vitro radical-scavenging, anti-obesity and hypoglycemic properties were investigated through the DPPH test, pancreatic lipase and α-amylase inhibition assays. Results showed that ‘Carolea’ extracted by Naviglio® was able to exert the best antioxidant activity and an excellent inhibitory effect on digestive enzymes with IC50 values equal to 1.27 ± 0.04 mg/mL and 33.21 ± 0.23 µg/mL for lipase and α-amylase inhibition, respectively.