Isolation and Assessment of a Highly-Active Anti-Inflammatory Exopolysaccharide from Mycelial Fermentation of a Medicinal Fungus Cs-HK1

Microbial exopolysaccharides: Unveiling the pharmacological aspects for therapeutic advancements

Microbial exopolysaccharides (EPSs) have emerged as a fascinating area of research in the field of pharmacology due to their diverse and potent biological activities. This review paper aims to provide a comprehensive overview of the pharmacological properties exhibited by EPSs, shedding light on their potential applications in various therapeutic areas. The review begins by introducing EPSs, exploring their various sources, significance in microbial growth and survival, and their applications across different industries. Subsequently, a thorough examination of the pharmaceutical properties of microbial EPSs unveils their antioxidant, immunomodulatory, antimicrobial, antidepressant, antidiabetic, antiviral, antihyperlipidemic, hepatoprotective, anti-inflammatory, and anticancer activities. Mechanistic insights into how different EPSs exert these therapeutic effects have also been discussed in this review. The review also provides comprehensive information about the monosaccharide composition, backbone, branches, glycosidic bonds, and molecular weight of pharmacologically active EPSs from various microbial sources. Furthermore, the factors that can affect the pharmacological activities of EPSs and approaches to improve the EPSs' pharmacological activity have also been discussed. In conclusion, this review illuminates the immense pharmaceutical promise of microbial EPS as versatile bioactive compounds with wide-ranging therapeutic applications. By elucidating their structural features, biological activities, and potential applications, this review aims to catalyze further research and development efforts in leveraging the pharmaceutical potential of microbial EPS for the advancement of human health and well-being, while also contributing to sustainable and environmentally friendly practices in the pharmaceutical industry.

Overexpression of phosphomannomutase increases the production and bioactivities of Ganoderma exopolysaccharides

In this study, we explored a novel approach to enhancing the production and bioactivities of Ganoderma exopolysaccharides. The homologous phosphomannomutase gene (PMM1) was cloned and overexpressed in Ganoderma for the first time. As a result, the maximum production of exopolysaccharides by the PMM1 transformant was 1.53 g/L, which was 1.41-fold higher than of a wild-type (WT) strain in a 5-L bioreactor. The transcription levels of PMM1 and PMM2 increased 40.5- and 2.4-fold, respectively, whereas the value of the GDP-D-mannose pyrophosphorylase gene did not change significantly in this transgenic strain. Furthermore, the major exopolysaccharide fractions from PMM1 transformants contained higher amounts of mannose (56.5 % and 21.1 %) than those from a WT strain (26.7 % and 9.3 %). Moreover, the major fractions from PMM1 transformants exhibited stronger regulation effects on macrophage. In conclusion, this study is helpful for the efficient production and application of Ganoderma exopolysaccharides and facilitates an understanding of polysaccharide biosynthesis regulation.

Synthetic Conditions, Physical Properties, and Antibacterial Activities of Silver Nanoparticles with Exopolysaccharides of a Medicinal Fungus

Natural polysaccharides are attractive and promising biomacromolecules for the green synthesis of silver nanoparticles (Ag NPs) with a broad spectrum of useful functions. This study aims to evaluate the synthetic conditions and physical properties of Ag NPs using three fractions of exopolysaccharide (EPS), namely EPS-1, EPS-2, and EPS-3, produced by a medicinal fungus known as Cs-HK1, with variations in their chemical composition and molecular weight. Each of the EPS fractions had a unique set of optimal synthetic conditions (reaction time course, temperature, and reagent concentration), resulting in a specific range of Ag NP size distributions. The Ag NPs synthesized with the EPS-1 fraction had the smallest particle size (~160 nm) and the most significant antibacterial activities against Escherichia coli (Gram-) and Staphylococcus aureus (Gram+), with a minimal inhibitory concentration (MIC) of 0.2 mg/mL on E. coli and 0.075 mg/mL on S. aureus. The results proved the success of the scheme of this green synthesis scheme with all three EPS fractions and the potential antibacterial application of EPS-coated Ag NPs.

Separation, Purification, Structural Characterization, and Anticancer Activity of a Novel Exopolysaccharide from Mucor sp

Mucor sp. has a wide range of applications in the food fermentation industry. In this study, a novel exopolysaccharide, labeled MSEPS, was separated from Mucor sp. fermentation broth through ethanol precipitation and was purified by ion-exchange chromatography, as well as gel filtration column chromatography. MSEPS was composed mostly of mannose, galactose, fucose, arabinose, and glucose with a molar ratio of 0.466:0.169:0.139:0.126:0.015 and had a molecular weight of 7.78 × 10⁴ Da. The analysis of methylation and nuclear magnetic resonance results indicated that MSEPS mainly consisted of a backbone of →3,6)-α-d-Manp-(1→3,6)-β-d-Galp-(1→, with substitution at O-3 of →6)-α-d-Manp-(1→ and →6)-β-d-Galp-(1→ by terminal α-l-Araf residues. MTT assays showed that MSEPS was nontoxic in normal cells (HK-2 cells) and inhibited the proliferation of carcinoma cells (SGC-7901 cells). Additionally, morphological analysis and flow cytometry experiments indicated that MSEPS promoted SGC-7901 cell death via apoptosis. Therefore, MSEPS from Mucor sp. can be developed as a potential antitumor agent.

Modification and enhanced anti-inflammatory activity by Bifidobacterial fermentation of an exopolysaccharide from a medicinal fungus Cs-HK1

The exopolysaccharide (EPS) from the mycelial fermentation of a medicinal fungus Cordyceps sinensis Cs-HK1 had shown significant anti-inflammatory activity previously, and EPS-LM was a highly active fraction with a relatively low molecular weight (MW) isolated from the Cs-HK1 EPS. This study was to assess the effects of Bifidobacterial fermentation in anaerobic conditions on the molecular properties and anti-inflammatory activity of EPS-LM. In both Bifidobacterial cultures (B. breve and B. longum), EPS-LM was fractionally consumed as a carbon source, increasing the bacterial growth and acetic acid production. Analytical results from the fermentation digesta (supernatant) suggested that EPS-LM was partially degraded to lower molecular weight (MW) products with modified structures during the Bifidobacterial fermentation. More interestingly, the higher MW digesta fraction containing the partially degraded EPS-LM showed even stronger inhibiting activity than the original EPS-LM on the LPS-induced pro-inflammatory responses in THP-1 cell culture, including NF-κB activation, release of NO, TNF-α and IL-8. The study has shown that the fermentation by selected Bifidobacterial strains is effective to modify natural polysaccharides with enhanced bioactivities.