BACKGROUND: Agaricus bisporus mushrooms were able to lower cholesterol levels in hypercholesterolaemic rats and it was suggested that dietary fibre might inhibit cholesterol absorption. However, A. bisporus extracts were also able to inhibit the 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCR, the key enzyme in the cholesterol biosynthetic pathway) and this might also contribute to the observed lowering of cholesterol levels in serum. RESULTS: The methanol-water extracts obtained from A. bisporus were able to inhibit up to 60% the HMGCR activity using an in vitro assay. The HMGCR inhibitory capacities depended on cultivation conditions, strains, etc. The potential inhibitors were not statins, they might be β-glucans able to scavenge the substrate and impair the enzymatic reaction. They were present during all mushroom developmental stages and similarly distributed through all the tissues including the parts discarded as a by-product. Accelerated solvent extractions using 1:1 ethanol-water as pressurised solvent (10.7 MPa, 25°C, five cycles of 5 min) were more effective in the extraction of the HMGCiR inhibitor(s) than supercritical fluid extractions (9 MPa, 40°C) using CO2 with 10% ethanol. CONCLUSION: A mushroom cultivation and two extraction procedures were optimised to obtain fractions from A. bisporus with high HMGCR inhibitory activities to design novel ingredients for hypocholesterolaemic functional foodstuffs.
BACKGROUND:Agaricus bisporus mushrooms were able to lower cholesterol levels in hypercholesterolaemic rats and it was suggested that dietary fibre might inhibit cholesterol absorption. However, A. bisporus extracts were also able to inhibit the 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCR, the key enzyme in the cholesterol biosynthetic pathway) and this might also contribute to the observed lowering of cholesterol levels in serum. RESULTS: The methanol-water extracts obtained from A. bisporus were able to inhibit up to 60% the HMGCR activity using an in vitro assay. The HMGCR inhibitory capacities depended on cultivation conditions, strains, etc. The potential inhibitors were not statins, they might be β-glucans able to scavenge the substrate and impair the enzymatic reaction. They were present during all mushroom developmental stages and similarly distributed through all the tissues including the parts discarded as a by-product. Accelerated solvent extractions using 1:1 ethanol-water as pressurised solvent (10.7 MPa, 25°C, five cycles of 5 min) were more effective in the extraction of the HMGCiR inhibitor(s) than supercritical fluid extractions (9 MPa, 40°C) using CO2 with 10% ethanol. CONCLUSION: A mushroom cultivation and two extraction procedures were optimised to obtain fractions from A. bisporus with high HMGCR inhibitory activities to design novel ingredients for hypocholesterolaemic functional foodstuffs.
Authors: Eva Tejedor-Calvo; Sergi García-Barreda; Sergio Sánchez; Asunción Morte; María de Las Nieves Siles-Sánchez; Cristina Soler-Rivas; Susana Santoyo; Pedro Marco Journal: Foods Date: 2022-01-23