Structural investigation of a novel heteropolysaccharide from the fruiting bodies of Boletus edulis

A novel acid polysaccharide from Boletus edulis: extraction, characteristics and antitumor activities in vitro

A novel cold-water-soluble polysaccharide (BEP), with a molecular weight of 6.0 × 10⁶ Da, was isolated from Boletus edulis. BEP consists of galactose, glucose, xylose, mannose, glucuronic, and galacturonic acid in a ratio of 0.34:0.28:0.28:2.57:1.00:0.44. The IR results showed that BEP was an acid polysaccharide, containing α-type and β-type glucoside bonds. MTT assay showed BEP could inhibit cell proliferation significantly. Morphological observation demonstrated that BEP-treated MDA-MB-231 and Ca761 cells exhibited typical apoptotic morphological features. Flow cytometry analysis revealed that BEP caused mitochondrial membrane potential collapse. Annexin V-FITC/PI staining indicated that BEP induced apoptosis of MDA-MB-231 and Ca761 cells through cell block in S phase and G₀/G₁ phase, respectively. Western blot results showed that BEP could increase the Bax/Bcl-2 ratios, promote the release of cytochrome C, and activate the expression of caspase-3 and caspase-9 in MDA-MB-231 and Ca761 cells. In conclusion, our results demonstrated that BEP could inhibit the proliferation of breast cancer cells and induce apoptosis through mitochondrial pathways.

In vitro prebiotic activities of oligosaccharides from the by-products in Ganoderma lucidum spore polysaccharide extraction

Until recently, a variety of oligosaccharides from fruits, vegetables and mushrooms have demonstrated positive prebiotic effects. Ganoderma lucidum, a well-known traditional medicine and tonic in East Asia, has been utilized in the prevention and treatment of a broad range of illnesses. In this study, each of three oligosaccharides was obtained from the polysaccharide extraction by-products of sporoderm: the unbroken and broken spores of Ganoderma lucidum (UB-GLS, B-GLS). Their molecular weight distribution, monosaccharide composition and preliminary structures were analyzed using gel permeation chromatography (GPC), GC-MS, UV and FTIR, respectively. All of the oligosaccharides were found to exhibit prebiotic activities, evaluated by detecting growth stimulation on Lactobacillus in vitro. Among these, UB-O80 and B-O80 displayed the most significant effects (p < 0.05) in these groups, and UB-O80 showed higher resistance to hydrolysis by artificial human gastric juice compared with inulin, giving a maximum hydrolysis rate of 1.65%. Compared with inulin media, Lactobacillus also revealed high tolerance to lower pH levels and simulated gastric juices in UB-O80 and B-O80 media. Compared with a control in gut microbiota fermentation, the abundance of some beneficial bacteria increased and some harmful bacteria declined in the groups of UB-O80 and B-O80. In conclusion, the results suggest that GLS oligosaccharides could be exploited as promising prebiotics for the enhancement of human health.

Until recently, a variety of oligosaccharides from fruits, vegetables and mushrooms have demonstrated positive prebiotic effects.

Sulfonation and Antioxidative Evaluation of Polysaccharides from Pleurotus Mushroom and Streptococcus thermophilus Bacteria: A Review

Human beings are equipped with antioxidant defense systems to neutralize free radicals as free radicals could damage macromolecules, subsequently resulting in serious diseases. Researchers have been attracted to search for potential natural antioxidants to reduce oxidative damage. Pleurotus and Streptococcus thermophilus have been chosen as sources of sustainable bioactive compounds that have been consumed for thousands of years. Polysaccharides are important bioactive components produced by Pleurotus mushrooms and Streptococcus thermophilus bacteria. Additionally, there is a continued interest in sulfonation of crude polysaccharides from both sources, since sulfonation has been found to improve or create new bioactive properties in polysaccharides. Both crude and sulfated polysaccharides with good antioxidant capacities have great potential for the further development as commercial products. This review focuses on characterization, sulfonation methods, and antioxidant capacity evaluations of polysaccharides from Pleurotus and S. thermophilus. Common antioxidant capacity assays, including the mechanisms underlying each assay, and various experimental procedures are also discussed.