Immunologically active O6-branched (1-->3)-beta-glucan from the lichen Thamnolia vermicularis var. subuliformis.
A lentinan-type gel-forming beta-glucan, Ths-2, has been isolated in about 1.5% yield from the alkali extract of the lichen Thamnolia vermicularis var. subuliformis, using ethanol fractionation, dialysis and gel filtration. The mean Mr of Ths-2 was determined by GP-HPLC to be 67 kD, and the optical rotation was measured to be -14 degrees. The structure of Ths-2 was further elucidated by methylation analysis by GC-MS, 1H- and 13C-NMR spectroscopy and selective enzymatic hydrolysis with exo-(1 --> 3)-beta-D-glucanase followed by analysis of oligosaccharides by HPAEC-PAD. Ths-2 was found to be consisting of a (1 --> 3)-beta-D-glucopyranosyl main chain with branches of a (1 --> 6) linked glucopyranosyl unit on every third unit of the main chain. Similar polysaccharide structures have been described from fungi, but this is the first report of a lentinan-type (1 --> 3)-beta-D-glucan from a lichen species. The immunomodulating activity of Ths-2 was tested in an in vitro anti-complementary assay, and proved to be strongly active.
Olafsdottir
E S
ES
Faculty of Pharmacy, University of Iceland, Hagi, Reykjavik, Iceland. elinsol@hi.is
Omarsdottir
S
S
Paulsen
B Smestad
BS
Wagner
H
H
D000818:Animals; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003171:Complement Pathway, Classical / Q000187:drug effects*; D005936:Glucans / Q000737:chemistry / Q000494:pharmacology*; D006168:Guinea Pigs; D008011:Lichens; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology*; D047071:beta-Glucans
D005936:Glucans; D010936:Plant Extracts; D011134:Polysaccharides; D047071:beta-Glucans; C064197:beta-1,6-glucan