Manganese phthalocyanine is a chemical compound of manganese and cyanide. Manganese is a naturally occurring metal with the symbol Mn and the atomic number 25. It does not occur naturally in its pure form, but is found in many types of rocks in combination with other substances such as oxygen, sulfur, or chlorine. Manganese occurs naturally in most foods and small amounts are needed to stay healthy, as manganese ions act as cofactors for a number of enzymes. (4, 5)
Structure for CHEM000978: Manganese phthalocyanine
Synonyms
Not Available
Chemical Formula
C32H22MnN8
Average Molecular Mass
573.509 g/mol
Monoisotopic Mass
573.135 g/mol
CAS Registry Number
14325-24-7
IUPAC Name
manganese(2+) ion 2,11,20,29,37,38,39,40-octaazanonacyclo[28.6.1.1³,¹⁰.1¹²,¹⁹.1²¹,²⁸.0⁴,⁹.0¹³,¹⁸.0²²,²⁷.0³¹,³⁶]tetraconta-1(36),3,5,7,9,12,14,16,18,21,23,25,27,30,32,34-hexadecaene-37,39-diide
Traditional Name
manganese(2+) ion 2,11,20,29,37,38,39,40-octaazanonacyclo[28.6.1.1³,¹⁰.1¹²,¹⁹.1²¹,²⁸.0⁴,⁹.0¹³,¹⁸.0²²,²⁷.0³¹,³⁶]tetraconta-1(36),3,5,7,9,12,14,16,18,21,23,25,27,30,32,34-hexadecaene-37,39-diide
belongs to the class of organic compounds known as phthalocyanines. These are cyclic tetrapyrroles that contain a phthalocyanine skeleton, which consists of four isoindole-type units, with the connecting carbon atoms in the macrocycle replaced by nitrogen.
Manganese is a cellular toxicant that can impair transport systems, enzyme activities, and receptor functions. It primarily targets the central nervous system, particularily the globus pallidus of the basal ganglia. It is believed that the manganese ion, Mn(II), enhances the autoxidation or turnover of various intracellular catecholamines, leading to increased production of free radicals, reactive oxygen species, and other cytotoxic metabolites, along with a depletion of cellular antioxidant defense mechanisms, leading to oxidative damage and selective destruction of dopaminergic neurons. In addition to dopamine, manganese is thought to perturbations other neurotransmitters, such as GABA and glutamate. In order to produce oxidative damage, manganese must first overwhelm the antioxidant enzyme manganese superoxide dismutase. The neurotoxicity of Mn(II) has also been linked to its ability to substitute for Ca(II) under physiological conditions. It can enter mitochondria via the calcium uniporter and inhibit mitochondrial oxidative phosphorylation. It may also inhibit the efflux of Ca(II), which can result in a loss of mitochondrial membrane integrity. Mn(II) has been shown to inhibit mitochondrial aconitase activity to a significant level, altering amino acid metabolism and cellular iron homeostasis. Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (2, 4)
Metabolism
Manganese is absorbed mainly via ingestion, but can also be inhaled. It binds to alpha-2-macroglobulin, albumin, or transferrin in the plasma and is distributed to the brain and all other mammalian tissues, though it tends to accumulate more in the liver, pancreas, and kidney. Manganese is capable of existing in a number of oxidation states and is believed to undergo changes in oxidation state within the body. Manganese oxidation state can influence tissue toxicokinetic behavior, and possibly toxicity. Manganese is excreted primarily in the faeces. Cyanide is rapidly alsorbed through oral, inhalation, and dermal routes and distributed throughout the body. Cyanide is mainly metabolized into thiocyanate by either rhodanese or 3-mercaptopyruvate sulfur transferase. Cyanide metabolites are excreted in the urine. (1, 4)
Manganese mainly affects the nervous system and may cause behavioral changes and other nervous system effects, which include movements that may become slow and clumsy. This combination of symptoms when sufficiently severe is referred to as “manganism”. (4)
Symptoms
Manganese mainly affects the nervous system and may cause behavioral changes and other nervous system effects, which include movements that may become slow and clumsy. This combination of symptoms when sufficiently severe is referred to as “manganism”. (4)
Treatment
Antidotes to cyanide poisoning include hydroxocobalamin and sodium nitrite, which release the cyanide from the cytochrome system, and rhodanase, which is an enzyme occurring naturally in mammals that combines serum cyanide with thiosulfate, producing comparatively harmless thiocyanate. Oxygen therapy can also be administered. (2)
