The Research of Gmelin Larch (Larix gmelinii (Rupr.) Rupr.) Gum

Abstract

The samples of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) gum, selected from a variety of trees and from different parts of the tree in vicinity of Ulan-Ude (Buryatia), were investigated with GPC, IR, quantitative NMR ¹³C spectroscopy and spectrophotometry methods. The samples were dissolved in distilled water at room temperature. The mechanical impurities were filtered, the transparent solutions were evaporated to dryness, and the dry residues were purified by reprecipitation from water to ethanol. The content of mechanical impurities was 0.1–4.8% of the mass of absolutely dry gum. Aqueous solutions of gum were weakly acidic, as well as arabinogalactan (AG) isolated from wood of Siberian and Gmelin larches. It is established that Gmelin larch gum is a high purity arabinogalactan (~99%) with minor impurities of flavonoids, tannins and mineral substances. Molecular-mass characteristics and monosaccharide composition of Gmelin larch gum arabinogalactan is similar to arabinogalactan obtained from wood of all previously studied species of larch growing in Siberia and the Far East. The data suggest recommending Gmelin larch gum for application in medicine and the veterinary, food and cosmetic industries.