Plant Mucilages. XXXIV. The Location of O-Acetyl Groups and the Structural Features of Plantago-Mucilage A, the Mucous Polysaccharide from the Seeds of Plantago major var. asiatica

The O-acetyl groups in Plantago-mucilage A, the representative mucous polysaccharide isolated from the seeds of Plantago major L. var. asiatica Decaisne (= Plantago asiatica L.), were located at position 2 of about one-fourth of L-arabinofuranosyl residues, about two-fifths of the terminal D-xylopyranosyl residues, and about one-ninth of the non-terminal D-xylopyranosyl residues. Reinvestigation of earlier methylation analysis results, showed that the mucilage possesses a main chain composed of β-l→4-linked D-xylopyranose residues having other β-D-xylopyranose units and branches composed of O-α-(D-glucopyranosyluronic acid)-(l →3)-α-L-arabinofuranose and of 0-a-(D-galactopyranosyluronic acid)-(l →3)-α-L-arabinofuranose at position 3 as side chains.