7-Dehydrocholesterol

Source: Wikipedia, the free encyclopedia.
"Provitamin D3" redirects here. For the inactive form of vitamin D3 synthesized from 7-dehydrocholesterol, see Cholecalciferol.
7-Dehydrocholesterol
Ball-and-stick model of 7-dehydrocholesterol
Names
IUPAC name
Cholesta-5,7-dien-3β-ol
Systematic IUPAC name
(1R,3aR,7S,9aR,9bS,11aR)-9a,11a-Dimethyl-1-[(2R)-6-methylheptan-2-yl]-2,3,3a,6,7,8,9,9a,9b,10,11,11a-dodecahydro-1H-cyclopenta[a]phenanthren-7-ol
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
 100.006.456 Edit this at Wikidata
MeSH 7-dehydrocholesterol
UNII
  • InChI=1S/C27H44O/c1-18(2)7-6-8-19(3)23-11-12-24-22-10-9-20-17-21(28)13-15-26(20,4)25(22)14-16-27(23,24)5/h9-10,18-19,21,23-25,28H,6-8,11-17H2,1-5H3/t19-,21+,23-,24+,25+,26+,27-/m1/s1-dehydrocholesterol ☒N
    Key: UCTLRSWJYQTBFZ-DDPQNLDTSA-N checkY
  • InChI=1/C27H44O/c1-18(2)7-6-8-19(3)23-11-12-24-22-10-9-20-17-21(28)13-15-26(20,4)25(22)14-16-27(23,24)5/h9-10,18-19,21,23-25,28H,6-8,11-17H2,1-5H3/t19-,21+,23-,24+,25+,26+,27-/m1/s1
    Key: UCTLRSWJYQTBFZ-DDPQNLDTBZ
  • O[C@@H]4C/C3=C/C=C1\[C@H](CC[C@]2([C@H]1CC[C@@H]2[C@H](C)CCCC(C)C)C)[C@@]3(C)CC4
Properties
C27H44O
Molar mass 384.638
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
The epidermal strata of the skin.

7-Dehydrocholesterol (7-DHC) is a

photochemically converted to vitamin D3 in the skin, therefore functioning as provitamin-D3. The presence of this compound in human skin enables humans to manufacture vitamin D3 (cholecalciferol). Upon exposure to ultraviolet UV-B rays in the sun light, 7-DHC is converted into vitamin D3 via previtamin D3 as an intermediate isomer. It is also found in the milk of several mammalian species.[1][2] Lanolin, a waxy substance that is naturally secreted by wool-bearing mammals, contains 7-DHC which is converted into vitamin D by sunlight and then ingested during grooming as a nutrient. In insects 7-dehydrocholesterol is a precursor for the hormone ecdysone, required for reaching adulthood.[3] It was discovered by Nobel-laureate organic chemist Adolf Windaus
.

Biosynthesis

It is synthesized from

lathosterol oxidase (lathosterol 5-desaturase). This is the next-to-last step of cholesterol biosynthesis.[4] Defective synthesis results in the human inherited disorder lathosterolosis resembling Smith–Lemli–Opitz syndrome.[4] Mice where this gene has been deleted lose the ability to increase vitamin D3 in the blood following UV exposure of the skin.[5]

Location

The skin consists of two primary layers: an inner layer, the

epidermis. The thickness of the epidermis ranges from 0.08 mm to greater than 0.6 mm (from 0.003 to 0.024 inches).[6] The epidermis comprises five strata; from outer to inner, they are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The highest concentrations of 7-dehydrocholesterol are found in the epidermal layer of skin—specifically in the stratum basale and stratum spinosum.[7]
The production of pre-vitamin D3 is, therefore, greatest in these two layers.

Radiation

Synthesis of pre-vitamin D3 in the skin involves

LEDs) can be used to produce the radiation.[9]

Another important consideration is the quantity of 7-dehydrocholesterol present in the skin. Under normal circumstances, ample quantities of 7-dehydrocholesterol (about 25–50 μg/cm2 of skin) are available in the stratum spinosum and stratum basale of human skin to meet the body's vitamin D requirements. 7-DHC insufficiency has been proposed as an alternate cause for Vitamin D deficiency.[10]

Sources

7-DHC can be produced by animals and plants via different pathways. It is not produced by fungi in significant amounts. It is made by some algae, but the pathway is poorly understood.[11] It can also be produced by some bacteria.[10]

Industrially, 7-DHC generally comes from

vegan D3.[13][14]

7-DHC is used for vitamin D3 synthesis via lanosterol in land animals, via cycloartenol in plants, and in algae together with another provitamin D ergosterol for D2. In fungi solely ergosterol is used for synthesis of D2 via lanosterol.[15]

Interactive pathway map

Click on genes, proteins and metabolites below to link to respective articles. [§ 1]

[[File:
VitaminDSynthesis_WP1531Go to articleGo to articleGo to articleGo to articlego to articleGo to articleGo to articleGo to articlego to articlego to articlego to articlego to articleGo to articleGo to articlego to articleGo to articlego to articlego to articlego to articleGo to articlego to article
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VitaminDSynthesis_WP1531Go to articleGo to articleGo to articleGo to articlego to articleGo to articleGo to articleGo to articlego to articlego to articlego to articlego to articleGo to articleGo to articlego to articleGo to articlego to articlego to articlego to articleGo to articlego to article
|alt=Vitamin D Synthesis Pathway (view / edit)]]
Vitamin D Synthesis Pathway (view / edit)
  1. ^ The interactive pathway map can be edited at WikiPathways: "VitaminDSynthesis_WP1531".

See also

References

  1. ^ "7-dehydrocholesterol". The American Heritage Stedman's Medical Dictionary. Houghton Mifflin Company. 21 January 2007.
  2. ^ "7-dehydrocholesterol". Answers.com. Archived from the original on 25 October 2012.
  3. ^ Young E (2012). "Thanks to one gene, this fly needs a cactus to escape Neverland". Not Exactly Rocket Science. Archived from the original on 2012-09-30. Retrieved 2012-09-28.
  4. ^
    PMID 12812989
    .
  5. S2CID 206502190
    .
  6. ISBN 0-8053-7211-3
    .
  7. ^
    PMID 9625080
    .
  8. PMID 6281884
    .
  9. PMID 28904394
    .
  10. ^
    PMID 31848400
    .
  11. PMID 23717318
    .
  12. PMID 16251641
    . [Vitamin D3] is produced commercially by extracting 7-dehydrocholesterol from wool fat, followed by UVB irradiation and purification [...] [Vitamin D2] is commercially made by irradiating and then purifying the ergosterol extracted from yeast
  13. ^ "Vitamin D". The Vegan Society.
  14. ^ Gangwar, Gourvendra (1 July 2023). "Formulation of Lichen Based Pill a Natural Source of Vitamin D3 with a High Absorption Rate by Ambrosiya Neo-Medicine Pvt. Ltd". International Journal of Biomedical Investigation: 1.
  15. S2CID 53437216
    . Retrieved December 2, 2023.
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