Bifunctional Systems of Amelanchier alnifolia Leaves Extract-Oligosaccharides with Prebiotic and Antidiabetic Benefits

<i>Amelanchier alnifolia</i> is a plant known for its nutritional and bioactive properties. Its leaves contain a high concentration of active compounds with significant antioxidant and antidiabetic effects, including strong α-glucosidase inhibitory potential. The combination of these bioactive leaf extracts with prebiotic substances, such as fructooligosaccharides (FOS), galactooligosaccharides (GOS), and chitooligosaccharides (COS), enables the development of functional systems with enhanced beneficial properties. In this study, process optimization for leaves extraction was performed using a Plackett-Burman screening design, which identified key parameters for further optimization using the Box-Behnken design. The optimal extraction conditions were determined as follows: methanol content 58.06%, solid-to-solvent ratio 26.03 <i>m</i>/<i>v</i>, and extraction time 73.56 min. These conditions yielded the highest the total phenolic content (TPC). A comparative analysis of different cultivars revealed significant variations in polyphenol content among them. The formulated lyophilized systems with GOS, FOS and COS positively influenced the chlorogenic acid release profile, while maintaining the extract's antidiabetic and antioxidant properties. FT-IR analysis confirmed the molecular interactions responsible for these effects. The prebiotic effectiveness of the systems was quantitatively evaluated using two key parameters: the prebiotic index (PI), and the prebiotic activity score (PAS). Microbiological analyses demonstrated the beneficial effects of prebiotic-enriched systems characterized by better prebiotic action on <i>Bifidobacterium</i> strains than the pure extract. These findings suggest that <i>A. alnifolia</i> leaf extracts, in combination with prebiotics, could serve as promising functional ingredients with potential applications in health-promoting and antidiabetic formulations.