Study on the physicochemical properties and immune regulatory mechanism of polysaccharide fraction from Aronia Melanocarpa fruit.

Aronia Melanocarpa (Michx.) Elliott fruit has been extensively used in the food and medicinal fields. This study aimed to analyze the physicochemical properties of a polysaccharide fraction (AMP2) isolated from this fruit for the first time and investigated its immune regulatory mechanism. The physicochemical properties of AMP2 were determined using high-performance gel permeation chromatography, PMP derivatization-high performance liquid chromatography, Ultraviolet spectroscopy, and infrared spectroscopy. The metagenomic technology was applied to investigate the regulatory effects and mechanisms of AMP2 on the gut microbiota of immunosuppressed mice. The results showed that molecular weight of AMP2 was 83,444 Da, which was mainly composed of D-arabinose, D-xylose, D-mannose, D-rhamnose and d-glucose, and both β-type and α-type glycosidic bonds contained in its structure. AMP2 changed the composition of gut microbiota by increasing the number of beneficial and probiotic bacteria, thereby regulated the intestinal mucosal immune system of host. AMP2 improved intestinal immune system response and antimicrobial capacity through positive regulation of the NOD-like receptor signaling pathway and neutrophil extracellular trap formation. The results demonstrate the potential of AMP2 in immune regulation, providing a new perspective for its subsequent development and contributing to the development and application of related health foods.