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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.

This study was to assess the anti-inflammatory potential of exopolysaccharide (EPS) produced by a medicinal fungus Cordyceps sinensis Cs-HK1. The EPS was isolated from the Cs-HK1 mycelial fermentation broth by ethanol precipitation and purified by deproteinization and dialysis. The EPS had a total sugar content of 74.8% and a maximum average molecular weight (MW) over 107 Da, and consisted mainly of glucose and mannose, and a small amount of galactose and ribose. In THP-1 and RAW264.7 cell cultures, EPS significantly inhibited lipopolysaccharide (LPS)-induced inflammatory responses of the cells including the release of NF-κB and several pro-inflammatory factors such as NO, TNF-α and IL-1β. In the murine model of LPS-induced acute intestinal injury, the oral administration of EPS to the animals effectively suppressed the expression of major inflammatory cytokines TNF-α, IL-1β, IL-10 and iNOS and alleviated the intestinal injury. The results suggest that the Cs-HK1 EPS has notable anti-inflammatory activity and can be a potential candidate for further development of new anti-septic therapeutics. To the best of our knowledge, this is the first report on the anti-inflammation of an EPS from C. sinensis fungal fermentation.

This study was to investigate the potential prebiotic function of exopolysaccharide (EPS) from a medicinal fungus and the relationship to the molecular properties by in vitro human fecal fermentation. The EPS from Cordyceps sinensis Cs-HK1 mycelial fermentation was processed into three fractions with different monosaccharide contents, a higher molecular weight (MW) and a lower MW attained by two-step ethanol precipitation, and an intermediate MW by ultrasound-degradation of EPS. All the EPS fractions were well utilized during 24–48 h of fecal fermentation, leading to significant increases in the short chain fatty acid (SCFA) production. The consumption rate and production level of SCFAs varied slightly with the different EPS fractions. The EPS also influenced the composition and diversity of the fecal microflora, increasing the relative abundance of Firmicutes but suppressing that of Proteobacteria, which may be a beneficial effect for human health. Overall the results have shown that the Cs-HK1 EPS has significant prebiotic activity which is dependent on its molecular properties.