Production, preliminary characterization, and bioactivities of exopolysaccharides from Pleurotus geesteranus 5(#)

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

Alpha-amylase inhibitors from mycelium of an oyster mushroom

The α-Amylase and α-glucosidase are two main enzymes involved in carbohydrate metabolism. This study was aimed at detecting alpha-amylase inhibitory activity from edible mushroom mycelia. Oyster mushroom was collected from a natural source, from Indian Institute of Technology (Banaras Hindu University) campus and was maintained in vitro in mycelial form. Chloroform, acetone, methanol, and water were used separately for extraction of an active constituent from mycelial cells grown, for 7 days, in potato dextrose broth. The extracts were tested for alpha-amylase inhibitory activity. Chloroform, acetone, and methanol extracts were found to have alpha-amylase inhibitory activity, with IC₅₀ values of 1.71, 224, and 383 μg/mL, respectively. Aqueous extract had no enzyme inhibitory activity. The acetone extract inhibited α-amylase non-competitively whereas chloroform extract showed competitive inhibition. Acetone extraction yielded highest total phenolic content (TPC) of 0.524 mM of gallic acid equivalent, whereas chloroform extraction resulted in lowest TPC of 0.006 mM. The HPLC and absorbance maxima of acetone and chloroform extracts suggest that the bioactive component responsible for enzyme inhibition could be glycoproteins in chloroform extract and catechins (flavonoids) in acetone extract. Thus, the mushroom mycelia under study may be exploited for production and purification of a lead compound for the development of the α-amylase inhibitory drug.

Anti-inflammatory and hepatoprotective effects of exopolysaccharides isolated from Pleurotus geesteranus on alcohol-induced liver injury

The present work investigated the hepatoprotective role of exopolysaccharides (EPS) isolated from the mushroom Pleurotus geesteranus with respect to alcohol-induced liver injury in mice. Based on a physico-chemical analysis, the EPS produced by Pleurotus geesteranus was identified as a heteropolysaccharide with α-glycosidic bond. The results revealed that prophylactic application of the EPS reduces detrimental alcoholic effects on the liver. This observation was followed by decreased levels of total cholesterol, triglycerides, CYP2E1 and pro-inflammatory mediators (TNF-α, IL-6, IL-1β, COX-2, NO and iNOS) in the liver homogenates, suggesting that the EPS exhibits anti-inflammatory and hepatoprotective effects. Moreover, the increased activity of hepatic enzymes (superoxide dismutase, glutathione peroxidase and catalase) and reduced lipid peroxidation status indicated that the antioxidative effect of the EPS contributes to alleviation of liver injury. Therefore, this study reports that the EPS produced by Pleurotus geesteranus could be considered a potential natural drug or functional food supplement for the prevention of liver damage.