Acidic Gums

Takahashi, N. Nambu, and T. Nagai, Chem. Pharm. Bull., 1978, 26, 3836. 

Kubala, and A. Malovikova, Collect. Czech. Chem. Commun., 1979, 44, 2517. 

The Hofman degradation has been applied to mangle gum, and a variety of fragments were obtained on borohydride ion reduction and acidic hydrolysis of the product. The same fragments were obtained on the Barry degradation of the Hofman-degraded product. The results supported the earlier conclusions about the structure of the gum. 

An analytical study of eight Acacia gums (four each from the Gummiferae and Vulgares series) has confirmed the main chemotaxonomic differences between the species that have been previously reported.  

During the methylation analysis of Combretum nigricans gum by the Hakomori procedure, losses of D-galacturonic acid and L-rhamnose residues were observed, which did not occur in the Haworth or a modified-Haworth procedure.However, during the Haworth procedure, C. nigricans gum was degraded to a greater extent than the gum from A cacia seyal. 

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See Fluorine Sodium bromate Gallic acid, Gum tragacanth... 

UmbellipreninS-hydroxy Gum Umbelliprenin9-hydroxy Gum 387.5 °° Undecyl sufonyl acetic acid Gum EO... 

Common suspending agents are poly(vinyl alcohols) of various molecular weights and degrees of hydrolysis, starches, gelatin, calcium phosphate (especially freshly precipitated calcium phosphate dispersed in water to be used in the preparation), salts of poly(acrylic acid), gum arabic, gum tragacanth, etc. 

Solvents, e.g., ethanol, acetone Cells, e.g., bakers yeast, brewers yeast Crude cellular extracts, e.g., yeast extract Organic acids, e.g., citric acid, lactic acid Vitamins and amino acids, e.g., lysine, ascorbic acid Gums and polymers, e.g., xanthan, geUan Antibiotics, e.g., peniciUins, rifampicin... 

Conclusive evidence for structure XVIII was obtained from a study of the action of alkali on it. While its UV-spectrum in ethanol had the absorption due to a saturated aliphatic ketone (A ,ax 220, 292 m/i, loge 1.98, 1.33), in alkaline ethanol the absorption was typical of an unsaturated ketone (An,ax 245,318m/Lt, loge 3.45,1.91). The latter function had clearly been generated by the elimination process illustrated. The a,)3-unsaturated ketone, isolated as a gum by acidification, on ozonolysis afforded acetaldehyde and an acidic gum. Mild pyrolysis of the latter gave carbon dioxide and a crystalline acid which was identified as (-I- )-)3-(propionic acid (XX) by direct comparison with the synthetic racemic modification. 

The sCf>aration must Be carried out in the same way, when mixtures of both sorts of gum with dextrin arc under Investigation. The copper precipitate, containing the acid gum products, is washed with distilled water, dissolved in hydrochloric add, and this solution... 

C ium is the inspissated Juice of the capsules of the poppy. It is of exceedingly complex composition, and contains, besides a neutral body called mecontn (probably a polyatomic alcohol, C H 0 ), a peculiar sciA meconie acid q. v.), lactic acid, gum, albumen, wax, and a volatile matter —no less than eighteen different alkaloids, one or two of which, how-ever, ai e probably formed during the process of extraction, and do not pre-exist in opium. 

Several naturally occurring anionic polysaccharides exist alginic acid, pectin, carrageenans, xanthan gum, hyaluronic acidic, gum exudates (gum arabic, karaya, traganth, etc.). Cross-linking sites that occur when a polyvalent cation (e.g. Ca +) causes interpolysaccharide binding are called "junction zones . 

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