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2D Structure
Also known as: 7782-49-2, Se, Selane, Selenium hydride, Selenium atom, Elemental selenium
Molecular Formula
Se
Molecular Weight
78.97  g/mol
InChI Key
BUGBHKTXTAQXES-UHFFFAOYSA-N
FDA UNII
V91P54KPAM

Selenium is a nonmetallic chemical element found in trace amounts in human body. Selenium primarily occurs in vivo as selenocompounds, mostly selenoproteins such as glutathione peroxidase and thioredoxin reductase (enzymes responsible for detoxification). Alone or in combination with Vitamin E, selenocompounds act as antioxidants. These agents scavenge free radicals; prevent blood clots by inhibiting platelet aggregation; strengthen the immune system; and have been shown, in some instances, to inhibit chromosomal damage and mutations. Exhibiting chemopreventive activity, selenocompounds also inhibit the induction of protein kinase C.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
selenium
2.1.2 InChI
InChI=1S/Se
2.1.3 InChI Key
BUGBHKTXTAQXES-UHFFFAOYSA-N
2.1.4 Canonical SMILES
[Se]
2.2 Other Identifiers
2.2.1 UNII
V91P54KPAM
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Hydrogen Selenide

2. Hydrogen Selenide, 75se-labeled

3. Selane

2.3.2 Depositor-Supplied Synonyms

1. 7782-49-2

2. Se

3. Selane

4. Selenium Hydride

5. Selenium Atom

6. Elemental Selenium

7. Selenium Elemental

8. Selenium, Elemental

9. Selen

10. Selenium And Compounds

11. Selenium Dihydride

12. Selenium Metallicum

13. Selenium Powder

14. Selenium Compounds

15. Ci 77805

16. Dihydrogen Monoselenide

17. C.i. 77805

18. Mfcd00134090

19. Hydrogen Selenide, Anhydrous

20. H6241uj22b

21. Vandex

22. Gray Selenium

23. Selenium Alloy

24. Selenium Base

25. Selenium Dust

26. Colloidal Selenium

27. Selen [polish]

28. Selenium, Metallic

29. Selenium Homopolymer

30. Selenium, Colloidal

31. Caswell No. 732

32. Selenio

33. Selenium Anhydride

34. Electronic E-2

35. Ccris 4250

36. Hsdb 4493

37. Einecs 231-957-4

38. Un2658

39. Hydrogen Selenide (h2se)

40. Epa Pesticide Chemical Code 072001

41. Selenium Compounds, N.o.s.

42. Selenium Metal

43. Unii-h6241uj22b

44. Selenium And Selenium Compounds

45. Hsdb 548

46. Selenium (powder)

47. Einecs 231-978-9

48. Selenium Shot, 4n

49. Un2202

50. Un3283

51. Selenium (iv) Hydride

52. Hydrogen Selenid

53. B-traxim Se

54. Selenium [mi]

55. Selenium [vandf]

56. Selenium Hydride (seh2)

57. Selenium [mart.]

58. 34se

59. Selenium [who-dd]

60. Unii-v91p54kpam

61. Ec 231-957-4

62. Selenium, Powder, 99+%

63. Selenium Compound, N.o.s.

64. Selenium Powder, -200 Mesh

65. Selenium Powder, -325 Mesh

66. Selsaf 2000

67. Hydrogen Selenide [mi]

68. Selenium, P.a., 99.5%

69. Chembl1235891

70. Dtxsid9021261

71. Chebi:27568

72. Hsdb 6909

73. Selenium Nanopowder In Aq. Media

74. Selenium Metallicum [hpus]

75. Selenium, Elemental [hsdb]

76. Mfcd00011224

77. Db11135

78. Nsc-605850

79. Nsc-605851

80. Nsc-605852

81. N725

82. Q876

83. Selenium, Pellets, < 5mm, >=99.999%

84. E1457

85. Ft-0701285

86. Selenium Ingot/button, ~38mm (1.5in) Dia

87. Selenium And Selenium Compounds [iarc]

88. C01529

89. Selenium Powder [un2658] [keep Away From Food]

90. Selenium Shot, Amorphous, 1-5mm (0.04-0.20in)

91. Selenium, Foil, 25x25mm, Thickness 3mm, 99.95%

92. Hydrogen Selenide, Anhydrous [un2202] [poison Gas]

93. S008000000

94. Selenium, Plasma Standard Solution, Specpure, Se 10g/ml

95. Selenium, Shots, 99.99999% (7n), Diameter 2-4 Mm

96. Selenium, Aas Standard Solution, Specpure?, Se 1000?g/ml

97. Selenium, Pellets, <5 Mm, >=99.99% Trace Metals Basis

98. Selenium, Powder, -100 Mesh, >=99.5% Trace Metals Basis

99. Selenium, Powder, -100 Mesh, 99.99% Trace Metals Basis

100. Selenium, Plasma Standard Solution, Specpure?, Se 1000?g/ml

101. Selenium, Oil Based Standard Solution, Specpure?, Se 1000?g/g

102. Selenium, Plasma Standard Solution, Specpure?, Se 10,000?g/ml

103. Selenium Compound, N.o.s. [un3283] [poison, Keep Away From Food]

104. Selenium, Lump, 3 Mm Max. Lump Size, Weight 100 G, High Purity 99.999%

105. Selenium, Lump, 3 Mm Max. Lump Size, Weight 20 G, High Purity 99.999%

106. Selenium, Lump, 3 Mm Max. Lump Size, Weight 50 G, High Purity 99.999%

107. Selenium, Pellets, <5 Mm Particle Size, >=99.999% Trace Metals Basis

108. Selenium Shot, Amorphous, 2-6mm (0.08-0.2in), Puratronic(r), 99.999% (metals Basis)

109. Selenium, Powder, 250 Max. Part. Size (micron), Purity 99.95%, Weight 100 G

110. Selenium, Powder, 250 Max. Part. Size (micron), Weight 50 G, Purity 99.95%

111. Selenium, Powder, Max. Particle Size 250 Micron, Weight 200 G, Purity 99.95%

112. Selenium, Rod, 99.9999% (6n), Diameter 20 Mm, Length 55 Mm, Approx. 74g

113. Selenium, Rod, 99.99999% (7n), Diameter 20 Mm, Length 55 Mm, Approx. 74 G

114. Se0

115. Selenium Atomic Spectroscopy Standard Concentrate 1.00 G Se, 1.00 G/l, For 1l Standard Solution, Analytical Standard

2.4 Create Date
2005-03-26
3 Chemical and Physical Properties
Molecular Weight 78.97 g/mol
Molecular Formula Se
Hydrogen Bond Donor Count0
Hydrogen Bond Acceptor Count0
Rotatable Bond Count0
Exact Mass79.91652 g/mol
Monoisotopic Mass79.91652 g/mol
Topological Polar Surface Area0 Ų
Heavy Atom Count1
Formal Charge0
Complexity0
Isotope Atom Count0
Defined Atom Stereocenter Count0
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Therapeutic Uses

/Experimental Therapy/ ... Se-methylselenocysteine (SeMSC), a naturally occurring organic Se product, is considered as one of the most effective chemopreventive selenocompounds. ... Compared with SeMSC, elemental Se at nano size (Nano-Se) possessed equal efficacy in increasing the activities of glutathione peroxidase, thioredoxin reductase, and glutathione S-transferase, but had much lower toxicity as indicated by median lethal dose, acute liver injury, survival rate, and short-term toxicity. /These/ results suggest that Nano-Se can serve as a potential chemopreventive agent with reduced risk of Se toxicity.

PMID:17728283 Zhang J et al; Toxicol Sci 101 (1): 22-31 (2008)


4.2 Drug Indication

For the supplementation of total parenteral nutrition to prevent hyposelenemia.


FDA Label


5 Pharmacology and Biochemistry
5.1 Pharmacology

Selenium is incorporated into many different selenoproteins which serve various functions throughout the body.


5.2 ATC Code

D - Dermatologicals

D11 - Other dermatological preparations

D11A - Other dermatological preparations

D11AC - Medicated shampoos

D11AC03 - Selenium compounds


5.3 Absorption, Distribution and Excretion

Absorption

Oral bioavailability of 90% when given as L-selenomethionine. Tmax of 9.17h.


Route of Elimination

Mainly excreted in urine as 1beta-methylseleno-N-acetyl-d-galactosamine and trimethylselenonium. The amount excreted as 1beta-methylseleno-N-acetyl-d-galactosamine plateaus at doses around 2microg after which the amount excreted as trimethylselenonium increases. Some selenium is also excreted in feces when given orally.


Elemental selenium .. is poorly absorbed.

Norderg, G.F. et al; Handbook on the Toxicology of Metals 3rd ed. Academic Press, Burlington, MA. 2007, p. 789


... The distribution and retention of inhaled selenious acid and selenium metal aerosols ... similar in size and chemical form to selenium aerosols that may be produced during fossil fuel combustion /were examined/. Beagle dogs were given 10 to 61 ug Se/kg of body weight by inhalation. Aerosols generated for the inhalation exposures were also collected and instilled into the upper respiratory tracts or stomachs of additional dogs to measure systemic absorption at these sites. Selenium-75, incorporated into the aerosols, was used to determine the Se content in the whole animal, excreta, and individual tissues as a function of time. Virtually all inhaled selenious acid aerosol was rapidly absorbed into the blood from the lungs, gastrointestinal tract, and the nasal membranes. Selenium metal aerosols were less rapidly absorbed. Selenium that was absorbed into the blood was translocated to the liver, kidney, spleen, and heart. Selenium-75 in these organs had a biological half-life of 30 to 40 days. Approximately 50% of the deposited Se was eliminated with a biological half life of 1.2 days. Urine was the major route of excretion, accounting for 70 to 80% of the excreted Se. The long-term component of the whole-body retention function for both inhaled aerosols had a half-life of about 34 days and accounted for about 20% of the initial Se dose. ... Although absorption of selenious acid into blood following inhalation was more rapid than absorption of selenium metal, once absorbed the disposition of both compounds was similar. 6845362

PMID:6845362 Weissman SH et al; Toxicol Appl Pharmacol 67 (3): 331-7 (1983)


5.4 Metabolism/Metabolites

Selenium supplements are typically available in the form of sodium selenite which is metabolized to selenide through either glutathione conjugation and subsequent reduction by glutathione reductase enzymes or reduction by thioredoxin reductases. Selenide is further metabolized to selenocystein by cysteine synthases and to selenophosphate by selenophosphate synthases. Selenide is also metabolized progressively to methyl-selenol, dimethyl selenide, then trimethylselenonium. Selenocysteine is degraded to methyl-selenol, pyruvate and ammonia by cysteine beta lyase. Selenocystein reacts with oxygen to form selenocysteine selenoxide which spontaneously degrades to methylselenic acid, pyruvate and ammonia. Methylselenic acid can be converted to methylselenol via conjugation with thiol groups on proteins like glutathione.


Selenium compounds are in part reduced in the body to elemental selenium... Much is metabolized to dimethyl selenide which is excreted by the lungs, imparting a garlic-like odor.

Thienes, C., and T.J. Haley. Clinical Toxicology. 5th ed. Philadelphia: Lea and Febiger, 1972., p. 209


5.5 Biological Half-Life

Half life was observed to increase with chronic dosing time. For day 1-2 half life was 1.7 days. For day 2-3 half life was 3 days. For day 3-14 half life was 11.1 days.


Whole body: 140 days; [TDR, p. 1075]

TDR - Ryan RP, Terry CE, Leffingwell SS (eds). Toxicology Desk Reference: The Toxic Exposure and Medical Monitoring Index, 5th Ed. Washington DC: Taylor & Francis, 1999., p. 1075


The distribution and retention of inhaled selenious acid and selenium metal aerosols which were similar in size and chemical form to selenium aerosols that may be produced during fossil fuel combustion /was studied/. Beagle dogs were given 10 to 61 ug Se/kg of body weight by inhalation. ... Approximately 50% of the deposited Se was eliminated with a biological half life of 1.2 days. ... The long-term component of the whole-body retention function for both inhaled aerosols had a half-life of about 34 days and accounted for about 20% of the initial Se dose.

PMID:6845362 Weissman SH et al; Toxicol Appl Pharmacol 67 (3): 331-7 (1983)


5.6 Mechanism of Action

Selenium is first metabolized to selenophosphate and selenocysteine. Selenium incorporation is genetically encoded through the RNA sequence UGA. This sequence is recognized by RNA ste loop structures called selenocysteine inserting sequences (SECIS). These structures require the binding of SECIS binding proteins (SBP-2) to recognize selenocystiene. The specialized tRNA is first bound to a serine residue which is then enzymatically processed to a selylcysteyl-tRNA by selenocystiene sythase using selenophosphate as a selenium donor. Other unidentified proteins are required as part of the binding of this tRNA to the ribosome. Selenoproteins appear to be necessary for life as mice with the specialized tRNA gene knocked out exhibited early embryonic lethality. The most important selenoproteins seem to be the glutathione peroxidases and thioredoxin reductases which are part of the body's defenses againts reactive oxygen species (ROS). The importance of selenium in these anti-oxidant proteins has been implicated in the reduction of atherosclerosis by preventing the oxidation of low density lipoprotein. Selenium supplementation is also being investigated in the prevention of cancer and has been suggested to be beneficial to immune function.