Plant Mucilages. XXVI. Isolation and Structural Features of a Mucilage, "Okra-mucilage F, " from the Immature Fruits of Abelmoschus esculentus

Abstract

A representative mucilage, named Okra-mucilage F, has been isolated from the immature fruits of Abelmoschus esculentus MOENCH (=Hibiscus esculentus L. ; Okra). The final preparation was homogeneous as determined by ultracentrifugal analysis, cellulose acetate membrane electrophoresis, and gel chromatography. Its water solution gave an intrinsic viscosity value of 30.1. It was composed of partially acetylated acidic polysaccharide and protein in a ratio of approximately 8.1 : 1.0, and its molecular weight was estimated to be about 1700000. Analysis of component sugars, together with reduction and methylation, and partial degradation studies showed that the polysaccharide moiety in the mucilage possesses a main chain having the repeation structure (1→4)-O-α-(D-galactopyranosyluronic acid)-(1→2)-O-α-L-rhamnopyranose, and that half the L-rhamnose residues in the main chain have branches composed of 4-O-β-D-galactopyranosyl D-galactopyranose at position 4.