| Summary: | In this study, polysaccharides from Xanthoria parietina, a wide spread lichenfrom central Europe, were isolated, purified and analyzed concerning thestructural features, in combination with functional investigation of the influenceon ,?1urine macrophage cell line RAW264.7 in vitro.Defatted dried lichen (140 g, WT) was submitted to consecutive cold water (4°C,12 h), freezing (-20°C) and thawing (room temperature), hot water (100°C) aswell as alkaline (0.5: M aq. NaOH) extractions (each in triplicate). Only hotaqueous extract, XH (2.8%, W/WT) was further fractionated by ion exchangechromatography to yield mainly H-1 (0.7%) and H-2 (0.4%) (W/WT) fractions.Chromatographic purification of the fractions by gel permeationchromatography yielded polysaccharides H-1-3 (0.39%) and H-2-1 (0.07%)(W/WT) with molecular weights Mwof 13.7 and 525 kDa respectively, prior toethanol precipitation, dialysis and lyophilisation.Monomers composition analysis by HPAEC-PADand GC-MSrevealed that H-1-3consisted mainly of glucose (> 98%), while H-2-1 was composed of man nose(74.3%), galactose (14.1%), glucose (9.8%) and rhamnose (1.8%) as well astrace of arabinose. O-/L-configuration of diastereomers analyzed by capillaryzone elactrophoresis (CZE) as well as the anomeric configuration by lH- and 13CNMRindicated the presence «-0- glucose in H-1-3 and c-D-manncse, «-0-galactose, u-D-glucose and c-t-Rhap in H-2-1. Subsequently, linkage sequenceswere determined by GC-MS analysis of partially methylated alditol acetates,nano-ESI QTOF-MS/MS analysis of oligosaccharides and 2D-NMR analysis ofnative polysaccharides and oligosaccharides. In nano-ESI-Q- TOF MS/MSanalysis, the use of silver adducts in positive-ion mode settings was establishedand found to be capable of rising A- and X-type fragment ions generated fromcross-ring cleavages, together with the rise of 8- and Y-type ions from theglycosidic bonds cleavages of the oligosaccharides prepared from H-1-3 but notH-2-1. For H-2-1, the use of chloride adduct in negative-ion mode settings wasbetter capable in rising similar type of fragment ions.
|
|---|