Multifunctional in vitro bioactivity of commonly consumed fruits: Inhibition of free radicals and hypoglycemic enzymes

Fruits are important sources of bioactive compounds with recognized antioxidant and hypoglycemic potential. This study evaluated the phenolic composition and in vitro antioxidant, anti-acetylcholinesterase (AChE), and hypoglycemic activities of ethanolic extracts from widely consumed fruits. Total phenolics and flavonoids were quantified by Folin–Ciocalteu and AlCl₃ methods, respectively. Antioxidant activity was assessed by DPPH, ABTS, and β-carotene assays, while hypoglycemic potential was evaluated via inhibition of α-amylase, α-glucosidase, and lipase. Açaí showed the highest phenolic (156.87 ± 0.52 mg GAE/g) and flavonoid contents (115.78 ± 0.91 mg QE/g), as well as the strongest antioxidant activity (IC 50 : 9.75 ± 0.43 µg/mL for DPPH). Red grape also exhibited high phenolic content (130.10 ± 0.33 mg GAE/g) and the most potent hypoglycemic activity, with superior inhibition of α-amylase (IC 50 6.32 ± 0.94 µg/mL) and α-glucosidase (IC 50 = 5.91 ± 0.62 µg/mL). Blueberry and strawberry showed the highest AChE inhibition (IC 50 ≈ 10.4–10.5 µg/mL). Additionally, açaí and guava demonstrated lipase inhibition comparable to orlistat (IC 50 ≈ 6.97 µg/mL). These results highlight açaí and red grape as promising sources of multifunctional bioactive compounds for nutraceutical applications targeting metabolic disorders.