Physicochemical properties and biofunctional activities of polysaccharides from carob (ceratonia siliqua) pod by microwave-assisted deep eutectic solvent extraction and its effects on human gut microbiota

This study investigated the physicochemical properties, biological activities, prebiotic potential, and gut microbiota modulation of polysaccharides extracted from carob (Ceratonia siliqua) pod powder (CPP) using microwave-assisted deep eutectic solvent systems. The major fraction of microwave-extracted polysaccharides (MPS-1) had an average molecular weight of 5.63 × 10³ kDa and a distinctive monosaccharide composition, including mannose, galactose, glucose, and glucuronic acid in unique proportions. At a concentration of 2 mg/mL, MPS-1 demonstrated significant DPPH and ABTS radical scavenging activities, achieving 57.8% and 87.0%, respectively, along with high antioxidant potential (FRAP: 76.6 μg/mL, TAC: 89.0 μg/mL, MC: 1188.00 μg/mL). MPS-1 also exhibited notable antidiabetic potential, inhibiting α-amylase by 97.67% and α-glucosidase by 79.84%. Its anticancer activity was indicated by inhibiting the proliferation of Caco-2 and MCF-7 carcinoma cells by 79.6% and 7.4%, respectively. MPS-1 also showed antibacterial efficacy against common foodborne pathogens (E. coli O157, Salmonella Typhimurium, S. aureus, and L. monocytogenes) while promoting the growth of beneficial gut microbiota (Bacteroidia, Actinobacteria, and Clostridia) and enhancing the production of SCFAs (acetic, propionic, and butyric acids) during fecal fermentation, suggesting its potential as a dietary fiber source.