Ultrasonic-assisted three-phase partitioning with deep eutectic solvents for extraction of Nostoc commune Vauch polysaccharide and its anti-ulcerative colitis activity.

This study explores the extraction of polysaccharides from Nostoc commune Vauch. using ultrasonic-assisted three-phase partitioning with deep eutectic solvents (UA-TPP-DES). Response surface methodology was used to determine the optimized UA-TPP-DES conditions as follows: a 1: 2 molar ratio of lauric acid to terpineol, 30 min of ultrasonication at 60 °C with 100 W power, 20 % moisture content, 20 % w/w (NH4)2SO4 concentration, and a 2: 1 top-to-bottom phase volume ratio. The UA-TPP-DES method significantly improved the polysaccharide extraction efficiency of N. commune (yielding NCP-DES-3, 7.31 %) compared to conventional water extraction (3.35 %). The structural features of NCP-DES-3 were characterized through various physical and chemical methods, including molecular weight determination, monosaccharide composition analysis, Fourier Transform Infrared Spectroscopy (FT-IR), Gas Chromatography-Mass Spectrometry (GC-MS), and Nuclear Magnetic Resonance (NMR) spectroscopy. Additionally, the dextran sulfate sodium (DSS)-induced ulcerative colitis model in Drosophila was used to study the anti-ulcerative colitis (UC) activity of NCP-DES-3. In vivo experiments showed that NCP-DES-3 improved the intestinal barrier by modulating intestinal epithelial cell (IEC) and intestinal stem cell (ISC) growth and differentiation. Our results demonstrated that the UA-TPP-DES approach is an eco-friendly and efficient strategy for polysaccharide extraction, while the bioactive polysaccharide, NCP-DES-3, shows promising potential as a natural therapeutic agent for UC.