Physicochemical Characterization, Hypoglycemic Activity, and Antioxidant Activity of the Ultrasonic-assisted Extracted Polysaccharides from Sanghuangporus sanghuang

Abstract

Introduction: Sanghuangporus sanghuang (S. sanghuang) is a precious macrofungus. Polysaccharides are the functional components in S. sanghuang and have a variety of biological activities. Ultrasonic-assisted extraction is an efficient method to extract polysaccharides. It is necessary to study the structure and biological activity of polysaccharides from S. sanghuang to make use of this macrofungal resource. Methods: The S. sanghuang polysaccharide (SSP) was extracted by ultrasonic-assisted extraction. The structure of SSP was characterized using monosaccharide composition and molecular weight distribution analysis, Ultraviolet-Visible spectrum (UV), Fourier Transform Infrared spectroscopy (FT-IR), Dynamic Light Scattering (DLS), X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). The hypoglycemic potential of SSP was assessed by measuring its ability to inhibit α-amylase and α-glucosidase. Additionally, the antioxidant capacity of SSP was evaluated using the Ferric Reducing Ability of Plasma (FRAP) assay, as well as its ability to scavenge ABTS+, DPPH, and OH free radicals. Results: The SSP was extracted by ultrasonic-assisted extraction, and the yield was 4.094±0.003%. Structural analysis revealed that SSP was an α-linked heteroglucan primarily composed of glucose. Its molecular weight distribution was uneven, mainly centered around 16.7 kDa and 5.1 kDa. SSP was an amorphous structure with a spherical surface and an average particle size of 129.17±5.12 nm in an aqueous solution. For α-amylase and α-glucosidase inhibition assay, IC50 values were 0.234±0.058 mg/mL and 1.173±1.009 mg/mL, respectively. The IC50 values for DPPH, ABTS+, and OH free radical scavenging assays were 0.047±0.009 mg/mL, 0.005±0.003 mg/mL, and 4.887±0.255 mg/mL, respectively. Therefore, SSP exhibited dose-dependent and strong α-amylase and α- glucosidase inhibition capacity, reducing power and radical scavenging activities. Discussion: These findings provide valuable insights for the development of functional polysaccharides with potential applications in nutraceuticals or therapeutic interventions for diabetes and oxidative stress-related disorders. Conclusion: In this study, an α-linked heteroglucan, known as SSP, demonstrated effective hypoglycemic activities and antioxidant capabilities, which were dependent on dosage. Our results contribute significantly to the development of polysaccharides possessing potential antioxidant and hypoglycemic qualities.