CHARACTERIZATION OF A BIOLOGICALLY-ACTIVE ARABINOGALACTAN FROM THE LEAVES OF PLANTAGO-MAJOR L

PMIa is a Type II arabinogalactan with anti-complementary activity iso lated from the leaves of Plantago major L. It has a molecular weight o f 77 000-80 000 Da and consists of arabinose (38%), galactose (49%), r hamnose (6%), galacturonic acid (7%) and 1.5% protein with hydroxyprol ine, alanine and serine as the main amino acids. Characterization of P MIa by methylation and GC-MS, methanolysis and GC, Smith degradation, weak acid hydrolysis, C-13-NMR, H-1-NMR, two-dimensional heteronuclear NMR and DEPT show that it consists of 1,3-linked galactan chains with 1,6-linked galactan side chains attached to position 6. The side chai ns are further branched in position 3 with 1,3-linked galactose residu es which have 1,6-linked galactose attached to position 6; these 1,3- and 1,6-linked galactose chains altogether probably form a network. Te rminal and 1,5-linked arabinose in furanose form are attached to the g alactan mainly through position 3 of the 1,6-linked galactose side cha ins. (C) 1998 Elsevier Science Ltd. All rights reserved.