POLYSACCHARIDES FROM THE SEEDS OF SENNA-MULTIJUGA

The seeds of Senna multijuga were extracted with water or 1% acetic ac id and treated with ethanol, resulting in two insoluble fractions. Aft er purification, the major one (FIA, 23%) was shown to be a galactoman nan (Man:Gal 2.3:1; [alpha] = +54.6; [eta] = 1340 ml g(-1)). It consis ts of a main chain of (1-->4)-linked beta-D-mannopyranosyl residues su bstituted at O6 by single-unit alpha-D-galactopyranosyl side chains. T he second fraction (FIB, 2.5%) was an O-acetyl-glucuronoarabinoxylan f rom the seed coats (O-acetyl 8.3 mol%; glucuronic acid 11.7%, Xyl:Ara ratio 20:1), which showed a predominance of 4-O-substituted Xylp units (84.4%), branched at O3 with non-reducing end units of Xylp, Araf and glucuronic acid. The O-acetyl positions in D-xylosyl units are at O2 (4.8%), O3 (4.4%) and O2,3 (0.9%). The ratio between O3 and O2 determi ned by C-13-nuclear magnetic resonance spectroscopy is 1.5:1.