Docynia delavayi (Franch.) Schneid polyphenols: Optimization of ultrasound-assisted extraction and bioactivity study

Docynia delavayi is a polyphenol-rich indigenous plant from China, known for its medicinal and edible properties. However, its bioactivities have been scarcely studied. This study aimed to establish an efficient ultrasound-assisted extraction (UAE) process for isolating D. delavayi polyphenols (DDP) and to systematically assess their bioactivities. Single-factor assays combined with response surface methodology were employed to determine optimal UAE conditions for DDP: 43% ethanol, 460 W ultrasonic power, 21 mL/g liquid-to-solid ratio, and 41 min extraction. In vitro evaluation showed that DDP exhibited excellent antioxidant (DPPH radical scavenging IC50 = 3.75 μg/mL) and carbohydrate digestion enzyme (α-Glucosidase and α-Amylase) inhibitory activity. Moreover, DDP also exhibited inhibitory effects on Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Salmonella. Metagenomic analysis revealed that DDP promoted species associated with short-chain fatty acid synthesis, such as Flavonifractor plautii and Eubacterium sp., while reducing pathogenic bacteria, including Shigella sonnei and Klebsiella pneumoniae. Untargeted metabolomics analysis showed that DDP modulated the intestinal metabolic profile and enriched pathways involved in Fatty acid biosynthesis, Fatty acid metabolism, and Fatty acid elongation in mitochondria. We believe that DDP, owing to its remarkable biological activity, may exhibit significant prebiotic effects, thereby modulating the gut microbiota and metabolic network, ultimately improving host health. This study elucidated an efficient UAE process and the diverse biological activities of DDP, providing an experimental foundation for its development as a natural functional ingredient and supporting high-value utilization of medicinal and edible plant resources.