Deep Eutectic Solvents for Efficient Extraction of Anthocyanins from Amelanchier alnifolia: Structural Characterization and In Vitro Biological Activity Evaluation

Single-factor experiments and response surface methodology were employed to optimize the extraction of anthocyanins from the fruits of Amelanchier alnifolia (Saskatoon berry) using deep eutectic solvents (DES). The extracted anthocyanins were characterized using Fourier-transform infrared spectroscopy (FTIR) and ultra-performance liquid chromatography–mass spectrometry (UPLC–MS). Optimal conditions were as follows: choline chloride:acetic acid (1:3 molar ratio, DES-3); water content, 60% (v/v); solid-to-liquid ratio, 1:20 (g/mL); extraction time, 50 min; extraction temperature, 30 °C. Under these conditions, the extraction yield reached 4.84 ± 0.18 mg/g, which was 1.88-fold higher than that obtained using ethanol, and the purity of the extracted anthocyanins was 9.28 ± 0.56%, representing a 1.44-fold increase compared with ethanol extraction. The DES-extracted anthocyanins were identified as anthocyanin glycosides, primarily cyanidin-3-O-glucoside, cyanidin-3-O-α-arabinose, delphinidin-3-O-galactoside, delphinidin-3-O-glucoside, and delphinidin-3-O-α-arabinopyranoside. The bioactivity of the extracts was evaluated using in vitro antioxidant assays and hypoglycemic tests. DES-3-extracted anthocyanins had IC 50 values of 54.56, 56.86, and 46.67 μg/mL for scavenging hydroxyl radicals, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and superoxide anions, respectively. On average, the antioxidant activity of DES-3-extracted anthocyanins was approximately 1.12-fold higher than that of ethanol-extracted anthocyanins. DES-3-extracted anthocyanins concentration-dependently inhibited both α-amylase and α-glucosidase, with IC 50 values of 26.78 and 22.95 μg/mL, respectively; these values are approximately 1.17-fold lower than the equivalent values for ethanol-extracted anthocyanins. DES-3 appears to be an efficient, green solvent for Saskatoon berry anthocyanins, yielding extracts with enhanced in vitro antioxidant and hypoglycemic activities. Graphical The alternative text for this image may have been generated using AI.