title: A high throughput colorimetric assay of β-1,3-D-glucans by Congo red dye.
abstract: Mushroom strains contain complex nutritional biomolecules with a wide spectrum of therapeutic and prophylactic properties. Among these compounds, β-d-glucans play an important role in immuno-modulating and anti-tumor activities. The present work involves a novel colorimetric assay method for β-1,3-d-glucans with a triple helix tertiary structure by using Congo red. The specific interaction that occurs between Congo red and β-1,3-d-glucan was detected by bathochromic shift from 488 to 516 nm (>20 nm) in UV-Vis spectrophotometer. A micro- and high throughput method based on a 96-well microtiter plate was devised which presents several advantages over the published methods since it requires only 1.51 μg of polysaccharides in samples, greater sensitivity, speed, assay of many samples and very cheap. β-D-Glucans of several mushrooms (i.e., Coriolus versicolor, Ganoderma lucidum, Pleurotus ostreatus, Ganoderma carnosum, Hericium erinaceus, Lentinula edodes, Inonotus obliquus, Auricularia auricular, Polyporus umbellatus, Cordyseps sinensis, Agaricus blazei, Poria cocos) were isolated by using a sequence of several extractions with cold and boiling water, acidic and alkaline conditions and quantified by this microtiter plate method. FTIR spectroscopy was used to study the structural features of β-1,3-D-glucans in these mushroom samples as well as the specific interaction of these polysaccharides with Congo red. The effect of NaOH on triple helix conformation of β-1,3-D-glucans was investigated in several mushroom species.
authors.affiliation: Chemical Engineering and Biotechnology Research Center and Departmental Area of Chemical Engineering of Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, Portugal.
authors.forename: Magda C
authors.initials: MC
authors.lastname: Semedo
authors.affiliation: Chemical Engineering and Biotechnology Research Center and Departmental Area of Chemical Engineering of Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, Portugal. Electronic address: akarmali@deq.isel.ipl.pt.
authors.forename: Amin
authors.initials: A
authors.lastname: Karmali
authors.affiliation: Department of Bioengineering, Centre for Biological and Chemical Engineering of Instituto Superior Técnico, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Fonseca
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D004396:Coloring Agents / Q000378:metabolism; D003224:Congo Red / Q000378:metabolism*; D003365:Costs and Cost Analysis; D057166:High-Throughput Screening Assays / Q000379:methods*; D011509:Proteoglycans; D012680:Sensitivity and Specificity; D013997:Time Factors; D047071:beta-Glucans / Q000032:analysis*
chemical_list: D004396:Coloring Agents; D011509:Proteoglycans; D047071:beta-Glucans; D003224:Congo Red; C010770:polysaccharide-K
keywords: 96-Well microtiter plate; Congo red dye; High-throughput assay; Mushroom strains; Triple helix structure; β-1,3-d-Glucan