Guaiac Resin

There are some differences in the regulation of US and EU antioxidants. The restrictions on synthetic antioxidants are more strict in the EU, e.g. TBHQ, THBP, anoxomer, ethoxyquin, guaiac resin and derivates of thiodipropionic acid are not permitted there. On the other hand, sulphur dioxide and sulphites, citric and tartaric acids and their salts and salts of EDTA are not listed as permitted antioxidants in the US. 

Guaiacin is a brownish, amorphous powder, obtained by a special method from guaiac wood. It is soluble in alcohol, is colored blue by oxidizers, is far more sensitive than guaiac resin, and serves as an excellent reagent for oxidases. Guaiacin is used in the form of a 5 per cent alcoholic solution, which keeps well in completely filled, dark-colored, well-stoppered bottles. 

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 ... 

Guaiacol derives its name from the fact that it is obtained by the distillation of a resin known as guaiac. It is also similarly obtained from beech wood. It yields a neutral ester with carbonic acid. 

Synonyms Guaiac Guaiacum Gum guaiac Gum guaiacum Resin guaiac... 

R/8602H] Resinfusion 8610] Resinfusion 8611. See Epoxy resin Resin guaiac. See Guaiac gum Resinogum DD. See Dammar Resinoid 1382. See Phenolic resin Resinoid benzoin. See Gum benzoin Resin olibanum. SeeOlibanum Resins, Manila elemi. See Elemi gum Resin tolu. See Balsam tolu (Myroxylon balsamum)... 

One modification of the guaiac test was the use of crystalline guaiaconic acid, prepared from the resin. Von Euler and Bolin (136) made the oxidation of this acid the basis of a semiquantitative assay, but their method does not give accurate data. 

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