Oligosaccharides from Phaseolus atropurpureus

Abstract

Three reducing oligosaccharides, I, 11, and 111, have been isolated in yields of 0.01-0.02% from the leaves of Phaseolus atropurpureus (cv. Siratro). Oligosaccharide I was identified as a tetrasaccharide comprising D-galactose and D-glucose (1 : 1). Compounds 11 and 111 proved to be disaccharides, the former comprising D-galactose and D-glucose and the latter L-arabinopyranose and D-glucose. The interglycosidic linkages have been assigned as follows: I, O-D-Galp 1-6 O-D- Galp 1-4 O-D- Gp 1-6 D-Gp or O-D- Galp 1-4 O-D-Gp, 1-6 O-D-Galp 1-6 D-Gp; 11, O-β-D-Galp 1-6 D-Gp; 111, O-L-Arap 1-6 D-Gp.