Nitrogenous pigment

Lemberg, R. Nitrogenous Pigments from the Fungus Coriolus sanguineus Polystic-tus cinnabarinus). Austral. J. Exp. Biol. Med. Sci. 30, 271 (1952). 

Let us finally consider the case of other two recently identified natural compounds, two nitrogenous pigments of unusual structure, named zoanthoxanthin (I) and 3-norzoanthoxanthin (II). 

In addition to tetrapyrrole pigments, foods contain many other nitrogenous pigments. These pigments are theoretically derived from ... 

Prota, G. (1980) Nitrogenous pigments in marine invertebrates, in Marine Natural Products - Chemical and Biological Perspectives, vol. Ill (ed. P.J. Scheuer), Academic Press, New York, London, pp. 141-178. 

Cobalt compounds have been in use for centuries, notably as pigments ( cobalt blue ) in glass and porcelain (a double silicate of cobalt and potassium) the metal itself has been produced on an industrial scale only during the twentieth century. Cobalt is relatively uncommon but widely distributed it occurs biologically in vitamin B12 (a complex of cobalt(III) in which the cobalt is bonded octahedrally to nitrogen atoms and the carbon atom of a CN group). In its ores, it is usually in combination with sulphur or arsenic, and other metals, notably copper and silver, are often present. Extraction is carried out by a process essentially similar to that used for iron, but is complicate because of the need to remove arsenic and other metals. 

Additives. Because of their versatility, imparted via chemical modification, the appHcations of ethyleneimine encompass the entire additive sector. The addition of PEI to PVC plastisols increases the adhesion of the coatings by selective adsorption at the substrate surface (410). PEI derivatives are also used as adhesion promoters in paper coating (411). The adducts formed from fatty alcohol epoxides and PEI are used as dispersants and emulsifiers (412). They are able to control the viscosity of dispersions, and thus faciHtate transport in pipe systems (413). Eatty acid derivatives of PEI are even able to control the viscosity of pigment dispersions (414). The high nitrogen content of PEIs has a flame-retardant effect. This property is used, in combination with phosphoms compounds, for providing wood panels (415), ceUulose (416), or polymer blends (417,418) with a flame-retardant finish. 

The reaction of dextrose with a nitrogen-containing compound, eg, amino acids or proteins, yields a series of intermediates which form pigments of varied molecular weight (Maikard reaction). The type of pigments produced is dependent on reaction conditions such as pH, temperature, and concentration of reactants. 

Cryotherapy with liquid nitrogen can be performed to treat melasma with different results. It produces lightening of the pigmented areas that are as much significantly striking as they are superficial. 

Allomelanins — These are structurally different compounds containing little or no nitrogen. They are considered polymers of phenolic compounds like catechol. Fnngi prodnce melanin pigments, predominantly dihydroxyphenylalanine (DOPA)-melanin and dihydroxynaphthalene (DHN)-melanin. ... 

Betalains are water-soluble nitrogen-containing pigments responsible for the red and violet (betacyanins class) and yellow (betaxanthins class) colors found in many flowers, fruits, and occasionally in vegetative tissues of plants of most families of the Caryophyllales order (except the Caryophyllaceae and Molluginaceae families, which have anthocyanins instead)." ... 

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