Water-Soluble Polysaccharides of Alfalfa (Medicago sativa (Fabaceae)) of Flora of Krasnoyarsk Krai

Abstract

Alfalfa is a very high-quality perennial leguminous grass with a long history of cultivation and application in traditional medicine in Russia. In addition, alfalfa is a valuable forage representative of the legume family, its acreage in Russia reaches 2.3–2.5 million ha. The polysaccharide complex (PSC) was isolated from the aerial part of alfalfa by aqueous extraction (pH = 9) and characterized by physicochemical methods. The content of uronic acids was 13.1 ± 0.9%, the quantitative content of impurity substances such as protein was 4.25 ± 0.28%, nucleic acids 0.0056 ± 0.0003%, and mineral impurities (ash content) 3.45 ± 0.18%. The PSC was studied by IR spectroscopy. The monomeric composition of PSC was characterized by chromatography-mass spectrometry (major monosugars arabinose, glucose and galacturonic acid). The molecular weight distribution of PSC was studied by the high-pressure exclusion chromatography method. Data demonstrated that the polysaccharide complex of the aerial part of alfalfa consists of three components with molecular weights of 1100 ± 60, 16 ± 2 and 7 ± 1 kDa. The fact that PSC is a mixture of seven polysaccharides was demonstrated by the column ion-exchange chromatography method.