Polysaccharides from higher plants

Examples of polysaccharides from higher plants include starch, cellulose, and exudate gums like arabinogalac-tan, guar gum, and gum arabic. 

SR066 Wagner, H., A. Proksch, I. Riess- SR076 Maurer, et al. Immunostimulant action of polysaccharides (heteroglycans) from higher plants. Preliminary communication. Arzneimittelforschung... 

Polysaccharides and their Respective Derivatives from Higher Plants... 

Belkin et al. 29> were first to examine various polysaccharide fractions from higher plants for their antitumor activity. They could demonstrate that many of these fractions produced haemorrhagic necrosis in different tumor types. In most cases, the polysaccharides were injected intraperitoneally into mice carrying Sarkoma 37 ascites tumor. The result was a progressive increase in cell volume and in cytoplasmic vacuolization. Osswald 30) found that tragacanth, gum arabic, and CMC reduced tumor cells in Ehrlich ascites carcinoma in female NMRE mice. The effect depended upon the dose, the route of injection, and the molecular size of the polysaccharides administered. 

In some cases with crude preparations from higher plants, it has been shown that the cell volume increased highly, and neoplasmic cell vacuolization was observed. As a result of the administration of polysaccharides, the membranes of Ascites cells showed increased permeability to solutes and, consequently, the cell inhibed more water and swelled. 

Attempts to produce cellulose from UDP-Glc using enzymes of isolated plasma membranes from higher plants have usually yielded the ( -1,3-linked glucan (callose) instead. This is a characteristic polysaccharide of plant wounds which, as healing occurs, is degraded and replaced by cellulose.140144 Callose... 

Wagner, H., Proksch, A., Riess-Maurer, I., Vollmar, A., Odenthal, S., Stuppner, H., Jurcic, K., Le Turdu, M., and Heur, Y.H. 1984. Immunostimulant action of polysaccharides (heteroglycans) from higher plants. Preliminary communication. Arzneim.-Forsch. 34, 659-661. 

Polysaccharides belong to the most important immunostimulants isolated from higher plants. Plants often synthetize active polysaccharides in their roots and the composition of these polysaccharides in the plant root may vary to climatic conditions therefore standardization of the plant extracts can be difficult. 

Other fundamental pathway to the discovery of anticancer chemotherapeu-tics is to identify the polysaccharides that counter the effects of mutated tumor suppressor gene p53. Mutated p53 gene is present in 50% of all human cancers studied in the literature [37-39]. This mutated gene will lose the ability to effectively bind to DNA. Therefore, the p21 protein cannot be produced and hence disturbs the process of controlled cell division that eventually leads to the formation of tumor [42] (see section Molecular Basis of Cancer Formation and Development ). It has already been demonstrated in the literature that PSP extracted from higher plants reduces cell proliferation by increasing... 

A SOLUBLE POLYSACCHARIDE FRACTION FROM HIGHER PLANTS A POSSIBLE PHYSIOLOGICAL SUBSTRATE OF THE CYTOSOLIC PHOSPHORYLASE ISOZYME... 

A Soluble Polysaccharide Fraction from Higher Plants A Possible Physiological Substrate of the Cytosolic Phosphorylase Isozyme 99... 

Polysaccharides are used to modify the flow characteristics of fluids, to stabilize suspensions, to flocculate particles, to produce emulsions, and to encapsulate materials. The majority of polysaccharide additives used by the food industry are extracted from higher plant tissue and seaweeds. Plants synthesize such polymers to serve as stmctural components of cell walls or as a source of stored energy. However, these polymers have potential problems because of their variations in cost, limited supply and chemical stmcture. 

The polysaccharides obtained from higher plants may be classified as homopolysaccharides (starch and cellulose) made up of a large number of monosaccharides of the same type, and heteropolysaccharides (mucilage, gum and pectin) made up of a large number of monosaccharides of different types. 

Cellulose is the most abundant of naturally occurring organic compounds for, as the chief constituent of the eell walls of higher plants, it comprises at least one-third of the vegetable matter of the world. The cellulose eontent of such vegetable matter varies from plant to plant. For example, oven-dried cotton contains about 90% cellulose, while an average wood has about 50%. The balance is composed of lignin, polysaccharides other than cellulose and minor amounts of resins, proteins and mineral matter. In spite of its wide distribution in nature, cellulose for chemical purposes is derived commerically from only two sources, cotton linters and wood pulp. 

However, oral administration of these polysaccharides had no effect. Hemi-celluloses from different higher plants caused regression of solid Sarkoma 180 in mice but not of ascites tumor. Arabinoglucuronoxylan isolated from wheat-straw hemicellulose was completely devoid of activity, whereas arabinoglucoxylan was highly active (Nakahara 31)). 

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