Rhamnopyranosylgalactofuranan, a new immunologically active polysaccharide from Thamnolia subuliformis.
A complex polysaccharide, Ths-3, consisting mainly of rhamnopyranosyl and galactofuranosyl units, has been isolated from the water extract of the lichen Thamnolia subuliformis using ethanol fractionation, dialysis, ion-exchange chromatography, gel filtration and preparative GP-HPLC. The mean M(r) of Ths-3 was determined to be 1450 kD, and the monosaccharide composition is gal/rha/glc/xyl/man in the ratio of 40:31:13:10:6. The structure of Ths-3 was further elucidated by methylation analysis by GC-MS and NMR spectroscopy and found to be basically composed of (1-->3)-linked beta-D-galactofuranosyl units with branches on C6, and rhamnosyl units being predominantly (1-->2)-linked with branches on C3 and C4, while some units are (1-->3)-linked. Glucose, mannose and galactofuranose are found as terminal units and glucose and mannose are also (1-->4)-linked, while xylose is only present as terminal units. The trisaccharide xylglcglc was detected after partial hydrolysis of the polysaccharide. The immunomodulating activity of Ths-3 was tested in an in vitro phagocytosis assay and the classical anticomplementary assay, and proved to be active in both tests. The authors suggest the trivial name thamnolan for Ths-3.
Olafsdottir
E S
ES
Institute of Pharmacy, Pharmacology and Toxicology, University of Iceland, Reykjavik, Iceland. elinsol@hi.is
Omarsdottir
S
S
Paulsen
B S
BS
Jurcic
K
K
Wagner
H
H
D002849:Chromatography, Gas; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003169:Complement Inactivator Proteins / Q000494:pharmacology*; D003171:Complement Pathway, Classical / Q000187:drug effects*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008011:Lichens; D009682:Magnetic Resonance Spectroscopy; D010587:Phagocytosis / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
D003169:Complement Inactivator Proteins; D010936:Plant Extracts; D011134:Polysaccharides; C402834:thamnolan