Ultrasound assisted hot water extraction of polysaccharides from Taraxacum mongolicum: Optimization, purification, structure characterization, and antioxidant activity.

Ultrasound assisted hot water extraction (UAHWE) was applied to extraction of polysaccharides from Taraxacum mongolicum with hot water as extract solvent. Experimental factors in UAHWE process were optimized by response surface methodology. The optimal extraction parameters to achieve the highest Taraxacum mongolicum polysaccharides (TMPs) yield (12.08 ± 0.14)% by UAHWE were obtained under the ultrasound power of 200 W, extraction temperature of 62°C, solid-to-liquid ratio of 1:20 g/mL, and extraction time of 40 min, and then the crude TMPs were further purified by DEAE-52 and Sephadex G-100 chromatography to obtain a homogenous polysaccharide fraction (TMPs-1-SG). Subsequently, the structure of TMPs-1-SG was characterized by UV-vis, Fourier transform infrared spectroscopy (FT-IR), high performance gel permeation chromatography (HPGPC), high performance liquid chromatography (HPLC), scanning electron microscope (SEM), transmission electron microscopy (TEM), and Congo red test. The results display that TMPs-1-SG with an average molecular weight of 5.49 × 104 Da was comprised of mannose (Man), galactose (Gal), xylose (Xyl), and arabinose (Ara) with a molar ratio of 39.85:52.61:27.14:6.30. Moreover, TMPs-1-SG did not contain a triple helix structure. Furthermore, TMPs-1-SG and TEM presented a sheet-like, rod-shaped, and irregular structure. Finally, the antioxidant activity of TMPs-1-SG was evaluated by in vitro experiment. The IC50 values of scavenging DPPH and OH radicals for TMPs-1-SG achieved 0.71 mg/mL and 0.75 mg/mL, respectively. The findings can provide an effective method for extracting polysaccharides from natural resources.

Polysaccharides from fungi: A review on their extraction, purification, structural features, and biological activities.

Fungi, as the unique natural resource, are rich in polysaccharides, proteins, fats, vitamins, and other components. Therefore, they have good medical and nutritional values. Polysaccharides are considered one of the most important bioactive components in fungi. Increasing researches have confirmed that fungal polysaccharides have various biological activities, such as antioxidant, immunomodulatory, anti-tumor, hepatoprotective, anti-aging, anti-inflammatory, and radioprotective activities. Consequently, the research progresses and future prospects of fungal polysaccharides must be systematically reviewed to promote their better understanding. This paper reviewed the extraction, purification, structure, biological activity, and underlying molecular mechanisms of fungal polysaccharides. Moreover, the structure-activity relationships of fungal polysaccharides were emphasized and discussed. This review can provide scientific basis for the research and industrial utilization of fungal polysaccharides.