Pyrogallol tannin

Pyro-elektrizitat,/. pyroelectricity- -gallolgerb-stoff, m. pyrogallol tannin, -galluss ure, /. pyrogallic acid (pyrogallol). 

Ranunculus sceleratus L. Shi Long Nei (Ground mulberry) (whole plant) Ranunculin, anemonin, 5-hydroxytryptamine, seratonin, protoanemonin, pyrogallol tannins.48 50 This herb is toxic. Relieve swelling, pain, antitoxin, treat lymphatic gland disorders, antirheumatic. 

Tannins, especially in natural waters, interfere with the yellow silicomolybdate method because of their yellow color. Thus 6.8 ppm of pyrocatechol tannins or 2.7 ppni of pyrogallol tannins give a color equal to 1.0 ppm of silica. Reduction of the yellow to molybdenum blue by sulfite at low acidity (pH 2.5) and measurement of light absorption at 620 nm avoid the problem, and at the same time elimihate interference by phosphate ion (309). 

Esophageal tumors can be enhanced in rats by feeding various plant tannins (Morton, 1972). The tannins that appear to be most active are the hydrolyzed pyrogallol tannins and the condensed catechol tannins. In both cases, the tannins increase the tumor yield and decrease the latency period for tumor development. Tannins are normal secondary plant products and many are associated with insect resistance. The exact mechanism of tumor enhancement by tannins remains unknown, but tannins are irritants and allergens. 

C7H6O5. Colourless crystals with one molecule of water, m.p. 253" C, sparingly soluble in water and alcohol. It occurs free in woody tissue, in gall-nuts and in tea, and is a constituent of the tannins, from which it can be obtained by fermentation or by acid hydrolysis. It gives a blue-black colour with Fe and is used in the manufacture 6f inks. On heating it gives pyrogallol. 

Pyrogallol, another oxygen scavenger (and a reaction product of tannins), often is used as a catalyst for HQ. 

Carbon dioxide is absorbed first using a potassium hydroxide solution. Oxygen is the next gas absorbed, using pyrogallol (the same oxygen scavenger produced from quebracho tannins). The glass absorption chamber also contains steel wool as a catalyst. 

Hydrolyzable tannins are comparatively restricted in the human diet and there are no human metabolic data. Studies in rats have indicated that some 63% of a dose of 1 g/kg commercial tannic acid is excreted unchanged in the feces accompanied by small amounts of gallic acid, pyrogallol, and resorcinol. Plasma after enzymic hydrolysis was found to contain 4-O-methylgallic acid, pyrogallol, and resorcinol. Urine also contained a small amount of gallic acid after enzymic hydrolysis. The most notable observation from this study is the failure of the gut microflora to metabolize the galloylglucoses efficiently, at least at this substantial dose. The viability or composition of the gut microflora was not reported. ... 

Tannin produces an orange-red or chocolate-red precipitate with an acid solution of niobic acid, and a yellow or light brown precipitate with acid solutions of tantalic acid. Pyrogallol and other polyhydroxy derivatives of benzene behave similarly. 

Pyrogallol (1) was first observed by Scheele in 1786 as a product of the dry distillation of gallic acid [149-91-7] (3,4,5-trihydroxybenzoic acid). Pyrogallol, which is of widespread occurrence in nature, is incorporated in tannins, anthocyanins, flavones, and alkaloids (1). 

Group III comprises tanning materials containing tannins derived from pyrogallol, and are not precipitated by bromine water and give a bluish-black coloration with ferric alum. These also are subdivided into (a) those which give the above characteristic reaction with nitrous acid, and (6) those which give no reaction or only a brown colour. 

Tannin is a commercially important substance that can be extracted from the wood, bark, or leaves of certain trees and other plants. Tannins are complex dark-colored polyhydroxy phenolic compounds, related to catechol or pyrogallol, and vary in composition from species to species. They have the important property of combining with the proteins of animal skins to produce leather. 

Figure 3. Polyphenolic patterns occurring in tannins. Key XVII, resorcinol A-pyrogallol B XVIII, resorcinol A-catechol B XIX, phtoroglu-cinol A-pyrogallol B and XX, phloroglucinol A-catechol B ring systems.

Catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, salicylic acid, tannin (gallic acid), distilled water, ethanol, FeCl3 6 H2O. 

It crystallizes in long silky needles with 1 Aq, odorless acidulous in taste eparingly soluble in cold vrater, very soluble in hot water and in aloohol its Rolutions are arid. When heated to 210°-215 (410°-419° F.) it yields CO, and pyrogallol (9. v.). Its solution does not pteripitato gelatin, nor the salts of the alkrioids, as does tannin. It mrms four series of salts. 

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