A water extract from Lentinula edodes (LWE) showed HMG-CoA reductase inhibitory activity but contained no statins. NMR indicated the presence of water-soluble α- and β-glucans and fucomannogalactans. Fractions containing derivatives of these polysaccharides with molecular weight down to approximately 1 kDa still retained their inhibitory activity. Once digested LWE was applied to Caco2 in transport experiments, no significant effect was noticed on the modulation of cholesterol-related gene expression. But, when the lower compartment of the Caco2 monolayer was applied to HepG2, some genes were modulated (after 24 h). LWE was also administrated to normo- and hypercholesterolemic mice, and no significant lowering of serum cholesterol levels was observed; but reduction of triglycerides in liver was observed. However, LWE supplementation modulated the transcriptional profile of some genes involved in the cholesterol metabolism similarly to simvastatin, suggesting that it could hold potential as a hypolipidemic/hypocholesterolemic extract, although further dose-dependent studies should be carried out.
Keywords: HMG-CoA reductase; cholesterol; eritadenine; low-density array; polysaccharides; shiitake.