Structure of the Acid-Stable Core-Polysaccharide Derived From the Seed Mucilage of Ocimum Basilicum

Abstract

Partial acid hydrolysis of the mucilage gave an acid-stable core- polysaccharide composed of glucose and mannose (10 : 2). Repeated methylation of the core-polysaccharide by the usual techniques gave chloroform-soluble and -insoluble fractions. Hakomori methylation of the two fractions, hydrolysis, conversion of the sugar derivatives into alditol acetates and their identification by g.l.c.revealed that the soluble fraction is a glucomannan-type polymer while the insoluble fraction is of the glucan type. Combined g.l.c.-m.s. of the derived alditol acetates indicated that the glucan fraction is a degraded cellulose material while the glucomannan-type fraction is a linear polymer with sugar residues linked by (1→4)-β-glycosidic bonds terminated at the non-reducing end by a unit of D-glucose and/or D- mannose. The presence of contiguous glucose as well as glucose and mannose units was indicated by isolation of the corresponding oligosaccharides from the core-polysaccharide. Thus, the core- polysaccharide was found to be a composite aggregate of degraded cellulose and glucomannan-type polymers.