Polysaccharides of foliose thalli of Pseudocyphellaria clathrata (De Not.) Malme, a fungus lichenized with a green photobiont, were extracted and chemically characterized. The thalli were successively extracted with water and 2% aqueous KOH, at 100 degrees C. After neutralization, the solution was subjected to freeze-thawing and Fehling treatment of the supernatant precipitated a structurally complex galactoglucomannan (GGM) that was identical to a similar fraction obtained from Pseudocyphellaria aurata (Ach.) Vainio, a fungus lichenized by the green alga Dictyochloropsis symbiotica. Isolated from the supernatant of the Fehling precipitation, was an arabinogalactomannoglucan (AGMG) that contained arabinose, galactose, mannose, and glucose in a 12:34:40:14 molar ratio. Methylation analysis showed 18 different structures, the principal being nonreducing galactofuranosyl end-units (25%) with the main chain composed by (1→3)-linked β-glucopyranosyl units, as seen by controlled Smith degradation.
polysaccharides, lichen, Pseudocyphellaria clathrata
Publication DOI: 10.1639/0007-2745(2005)108[118:PPBTCP]2.0.CO;2Journal NLM ID: 100955480Publisher: American Bryological and Lichenological Society
Correspondence: lucimaramcc@yahoo.com, iacomini@ufpr.br
Institutions: Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná—UNIOESTE, CEP 85819-110, Cascavel, PR, Brazil, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-990, Curitiba, PR, Brazil
Methods: 13C NMR, 1H NMR, methylation, GC-MS, acid hydrolysis, Smith degradation, composition analysis, HPSEC, acetylation, alkaline extraction
Found