RESUMO
A fucomannogalactan from Rhizoctonia solani biomass was obtained after hot aqueous extraction and purified by freeze-thaw cycles and gel filtration chromatography on Sepharose CL-6B. The polysaccharide was homogeneous after HPSEC/RID analysis (Mw/Mn~1.1), displaying an average molecular weight of 15.4×103Da. Its chemical structure was determined by methylation analysis (GC/MS) and spectroscopy (FTIR, 1D and 2D NMR). The polysaccharide had a branched α-1,6-linked Galp backbone with 66% linear residues, a number of which were at O-3 methylated. Side chains (34%) were always linked at O-2 positions of the main chain and consisted of single, non-reducing ends of α-d-Manp (6%) and α-l-Fucp (28%). Analysis of its biological activity showed that the highly purified fucomannogalactan from R. solani inhibited the proliferation of colon cancer cells in vitro, but that it did not have the same activity against lung cancer cells.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Galactanos/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Rhizoctonia/química , Antineoplásicos/isolamento & purificação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/patologia , Humanos , Peso Molecular , Polissacarídeos/isolamento & purificação , Água/químicaRESUMO
A water-soluble polysaccharide was extracted with alkali from the cell wall of Verticillium lecanii (also called Lecanicillium lecanii). After freezing and thawing, the water-soluble fraction was purified by gel filtration chromatography on Sepharose CL-6B and eluted as one peak by HPSEC/RID. Monosaccharide analysis showed galactose and glucose (1.1:1), with traces of mannose (<1%). The structural characteristics were determined by spectroscopic analysis, FT-IR and 1D and 2D (1)H and (13)C NMR, and methylation results. On the basis of the data obtained, the following structure of the polysaccharide (E3SIV fraction) was established: [Formula: see text] where n≈22 and m≈22.
