Gums plant, constitution

Preliminary investigations into the constitution of plant gums have been directed to the isolation of disaccharides or aldobionic acids which are relatively easy to identify. Thus the structures of the aldobionic... 

Protocatechuic Acid.—One of the di-hydroxy benzoic acids is related to vanillin, which we have already studied. The acid is known as protocatechuic acid, and derives its name from the fact that it may be obtained from a gum or resin, known as gum catechin by fusion with potash, i.e. by heat and oxidation in presence of an alkali. A large variety of plant products including alkaloids essential oils, gums, resins and tannins yield this acid. The following may be mentioned gum catechin, gum benzoin, guaiac resin, myrrh, piperine or piperic acid, vanillin, cafe-tannic acid. These natural sources at once suggest a relationship to vanillin (p. 661) and heliotropin (p. 662). It is the acid corresponding to protocatechuic aldehyde, 3-4-di-hydroxy benzal-dehyde (p. 661), which explains the relationship just mentioned. Its constitution, is then ... 

Gums—are substances of unknown constitution, existing in plants amorphous soluble in water, insoluble in alcohol converted into glucose by boiling with dilute H,SO,. 

Opium, Gum opium crude opium. Air-dried, milky exudation from incised, unripe capsules of Papaver somniferum L., Or jP. album Mill., Papaveraceae. Habit of the plant Asia Minor, Persia, China, Africa, India cultivated in tlie Balkan States, Hungary, Southern Russia. In Japan the strain cultivated from the production of opium is called Ikkanshu Appearance and sources Chem. A Eng. News 32, 2701 (1954). Conshf, About 20 alkaloids, constituting about 25% of the opium meconic acid, some lactic and sulfuric acids, sugar, resinous and waxy-like subsrances 12 25% water. Morphine is the most important alkaloid and occurs to the extent of 10-16%, noscapine 4-8%, codeine 0 8-2.5%, papaverine 0 5 2,5%, thebaine 0,5-2%,... 

Carbohydrates constitute the main constituents of plants, with.cellulose the most abundant. In addition, are the various hemicelluloses or polysaccharides, pentosans and polyuronides. Most of these substances, especially cellulose, are readily attacked by many species of soil microorganisms. The result is that the carbohydrate content of humus is very different from that of the plant residues from which most of the humus is derived (Gupta, 1962 Gupta et al, 1963 Gupta and Sowden, 1964). Humus usually contains little cellulose but does contain hemicelluloses and polyuronides. These substances are in part the residues of the original plant materials but most of them are the synthesized gums, slimes and cell walls of the microorganisms that are responsible for decomposition and the formation of humus. 

The most extensively studied exudate gum from this plant family is that from Anogeissus latifolia which is known as gum ghatti or Indian gum (Chap. 10.2.6). This polysaccharide has a main chain of alternating )8-D-glucopyranosyluronic acid units substituted at 0-4 and D-mannopyranosyl units substituted at 0-2 (30, 162). The D-mannopyranosyl units constitute double branch points. The side chains contain L-arabinopyranosyl, L-arabinofuranosyl, D-galactopyranosyl, and D-glucopyranosyluronic acid units. 

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