Purification, structural characterization, and PCSK9 secretion inhibitory effect of the novel alkali-extracted polysaccharide from Cordyceps militaris

One novel alkali-extracted polysaccharide, CM3-SII, was obtained from the fruiting body of C. militaris via column chromatography. Its structural characteristics were investigated via chemical and spectroscopic methods. The backbone of CM3-SII was composed of -> 4)-beta-D-Manp(1 ->, -> 6)-beta-D-Manp(1 ->, and -> 6)-alpha-D-Manp(1 -> glyco-syls, and branching at the O-4 positions of -> 6)-beta-D-Manp(1 -> glycosyls with beta-D-Galp, (1 -> 2) linked-beta-D-Galf, and -> 2,6)-alpha-D-Manp(1 -> residues. Furthermore, O-6 and O-2 positions of the -> 2,6)-alpha-D-Manp(1 -> residues were substituted with methyl and beta-D-Galp, respectively. This polysaccharide significantly enhanced the intra-cellular protein expression of low-density lipoprotein receptor and proprotein convertase subtilisin/kexin type 9 (PCSK9) via regulating sterol regulatory element-binding protein 2 in hepatoma Huh7 cells. Of note, CM3-SII significantly decreased PCSK9 secretion at the concentration of 200 mu g/mL. Collectively, CM3-SII is different from the previously reported alkali-extracted polysaccharides isolated from the fruiting body of C. militaris, and it may have potential application in hypolipidemia or as a pharmaceutical additive.& nbsp; (c) 2021 Elsevier B.V. All rights reserved.