Structure, rheology and antioxidant properties of a polysaccharide from Atractylodes macrocephala in Pan'an

To date, no studies have reported on the structure and properties of the polysaccharides from Atractylodes macrocephala cultivated in Pan'an. In this paper, a polysaccharide designated as RAMP1 was isolated from A. macrocephala in Pan'an for the first time. Its structure was determined as a heteropolysaccharide consisting of fructose and glucose in a molar ratio of 20:1, with a molecular weight of 3494 Da based on chemical and NMR analysis. Scanning electron microscopy analysis revealed that RAMP1 presented a smooth flake structure with irregular curls. Thermal analysis results indicated that RAMP1 had high thermal stability below 165 °C. Rheological studies indicated that both temperature and concentration affected the viscosity of RAMP1. The viscosity of the RAMP1 solution decreased as the shear rate increased, displaying shear - thinning behavior, suggesting that the RAMP1 solution was a non - Newtonian fluid. RAMP1 showed potent dose - dependent antioxidant activity against DPPH, superoxide, ABTS, and hydroxyl radicals, with the strongest inhibition against hydroxyl radicals (83.97 ± 1.62 % at 8 mg/mL). This paper reports for the first time on the structure, rheology, and antioxidant properties of the polysaccharide (RAMP1) from A. macrocephala in Pan'an. These results highlight the potential applications of RAMP1 in the food and biotechnology industries.