Retinyl palmitate

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Retinyl palmitate
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Names
IUPAC name
Retinyl hexadecanoate
Systematic IUPAC name
(2E,4E,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-yl hexadecanoate
Other names
Retinol palmitate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.001.117 OOjs UI icon edit-ltr-progressive.svg
KEGG
PubChem CID
UNII
  • InChI=1S/C36H58O3/c1-7-8-9-10-11-12-13-14-15-16-17-18-19-25-34(37)39-35(38)29-31(3)23-20-22-30(2)26-27-33-32(4)24-21-28-36(33,5)6/h20,22-23,26-27,29H,7-19,21,24-25,28H2,1-6H3/b23-20+,27-26+,30-22+,31-29+ Yes check.svgY
    Key: SLCSFDSJAUMVCI-UQEJEMEYSA-N Yes check.svgY
  • InChI=1/C36H58O3/c1-7-8-9-10-11-12-13-14-15-16-17-18-19-25-34(37)39-35(38)29-31(3)23-20-22-30(2)26-27-33-32(4)24-21-28-36(33,5)6/h20,22-23,26-27,29H,7-19,21,24-25,28H2,1-6H3/b23-20+,27-26+,30-22+,31-29+
    Key: SLCSFDSJAUMVCI-UQEJEMEYBQ
  • CC1(C)CCCC(\C)=C1\C=C\C(\C)=C\C=C\C(\C)=C\C(=O)OC(=O)CCCCCCCCCCCCCCC
Properties
C36H60O2
Molar mass 524.86 g/mol
In water, ethanol and ethers [1]
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals. [2]

Contents

An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen.[ citation needed ]

In 2021, vitamin A was the 298th most commonly prescribed medication in the United States, with more than 500,000 prescriptions. [3] [4]

Biology

Animals use long-chain esters of vitamin A, most abundantly the palmitate form, as a form of vitamin A storage. The storage reaction is catalyzed by LRAT, and the inverse is catalyzed by REH. [2] The esters are also intermediates in the visual cycle: RPE65 isomerizes the retinyl part to 11-cis-retinal. [2]

Uses

Vitamin A palmitate is a common vitamin supplement, available in both oral and injectable forms for treatment of vitamin A deficiency, under the brand names Aquasol A, Palmitate A and many others. It is a constituent of intra ocular treatment for dry eyes at a concentration of 138 μg/g (VitA-Pos) by Ursapharm. It is a pre-formed version of vitamin A; therefore, the intake should not exceed the Recommended Dietary Allowance (RDA). Overdosing preformed Vitamin A forms such as retinyl palmitate leads to adverse physiological reactions (hypervitaminosis A). [5]

Retinyl palmitate is used as a source of vitamin A added to low fat milk and other dairy products to replace the vitamin content lost through the removal of milk fat. Palmitate is attached to the alcohol form of vitamin A, retinol, in order to make vitamin A stable in milk.[ citation needed ]

Retinyl palmitate is also a constituent of some topically applied skin care products. After its absorption into the skin, retinyl palmitate is converted to retinol, and ultimately to retinoic acid (the active form of vitamin A present in Retin-A), though neither its skin absorption [6] nor its conversion [7] is very effective.

Carcinogenicity controversy

New York Senator Chuck Schumer has called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals, [8] fueling the sunscreen controversy in the popular press. [9] One toxicological analysis determined that "there is no convincing evidence to support the notion that [retinyl palmitate] in sunscreens is carcinogenic." [9] A technical report issued thereafter by the National Toxicology Program concluded that diisopropyl adipate increased incidence of skin tumors in mice, and the addition of either retinoic acid or retinyl palmitate both exacerbated the rate and frequency of tumors. [10]

Teratogenicity

World Health Organization recommendation on Maternal Supplementation During Pregnancy states that "health benefits are expected for the mother and her developing fetus with little risk of detriment to either, from a daily supplement not exceeding 10,000 IU [preformed] vitamin A (3000 μg RE) at any time during pregnancy." [11] Preformed Vitamin A refers to retinyl palmitate and retinyl acetate.[ citation needed ]

See also

Related Research Articles

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The term carotene (also carotin, from the Latin carota, "carrot") is used for many related unsaturated hydrocarbon substances having the formula C40Hx, which are synthesized by plants but in general cannot be made by animals (with the exception of some aphids and spider mites which acquired the synthesizing genes from fungi). Carotenes are photosynthetic pigments important for photosynthesis.

<span class="mw-page-title-main">Vitamin A</span> Essential nutrient

Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most notably β-carotene (beta-carotene). Vitamin A has multiple functions: growth during embryo development, maintaining the immune system, and healthy vision. For aiding vision specifically, it combines with the protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light and color vision.

<span class="mw-page-title-main">Retinol</span> Chemical compound

Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. Dietary sources include fish, dairy products, and meat. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xerophthalmia. It is taken by mouth or by injection into a muscle. As an ingredient in skin-care products, it is used to reduce wrinkles and other effects of skin aging.

<span class="mw-page-title-main">Cod liver oil</span> Dietary supplement derived from liver of cod fish

Cod liver oil is a dietary supplement derived from liver of cod fish (Gadidae). As with most fish oils, it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and also vitamin A and vitamin D.

<span class="mw-page-title-main">Hydrocortisone</span> Glucocorticoid and Mineralocorticoid hormone Cortisol supplied as a medication

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<span class="mw-page-title-main">Tretinoin</span> Medication

Tretinoin, also known as all-trans retinoic acid (ATRA), is a medication used for the treatment of acne and acute promyelocytic leukemia. For acne, it is applied to the skin as a cream, gel or ointment. For acute promyelocytic leukemia, it is effective only when the RARA-PML fusion mutation is present and is taken by mouth for up to three months. Topical tretinoin is also the most extensively investigated retinoid therapy for photoaging.

<span class="mw-page-title-main">Retinoid</span> Group of tetraterpenes

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<span class="mw-page-title-main">Jagannath Ganguly</span>

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References

  1. ↑ William M. Haynes (2014–2015). CRC Handbook of Chemistry and Physics (95th ed.). CRC Press. p. 622. ISBN   978-1-4822-08672..
  2. 1 2 3 O'Byrne, SM; Blaner, WS (July 2013). "Retinol and retinyl esters: biochemistry and physiology". Journal of Lipid Research. 54 (7): 1731–43. doi: 10.1194/jlr.R037648 . PMC   3679378 . PMID   23625372.
  3. ↑ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
  4. ↑ "Vitamin A - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
  5. ↑ Vitamin A, Linus Pauling Institute
  6. ↑ E. A. Duell, S. Kang & J. J. Voorhees (1997). "Unoccluded retinol penetrates human skin in vivo more effectively than unoccluded retinyl palmitate or retinoic acid". The Journal of Investigative Dermatology . 109 (3): 301–305. doi: 10.1111/1523-1747.ep12335788 . PMID   9284094.
  7. ↑ Boehnlein, James; Sakr, Adel; Lichtin, J. Leon; Bronaugh, Robert L. (1994). "Characterization of Esterase and Alcohol Dehydrogenase Activity in Skin. Metabolism of Retinyl Palmitate to Retinol (Vitamin A) During Percutaneous Absorption". Pharmaceutical Research. 11 (8): 1155–1159. doi:10.1023/A:1018941016563. ISSN   0724-8741. PMID   7971717. S2CID   25458156.
  8. ↑ "Possible link between ingredient in sunscreen and skin cancer: Schumer". New York Daily News . June 14, 2010.
  9. 1 2 Wang, SQ; Dusza, SW; Lim, HW (2010). "Safety of retinyl palmitate in sunscreens: a critical analysis". Journal of the American Academy of Dermatology. 63 (5): 903–6. doi:10.1016/j.jaad.2010.07.015. PMID   20692724.
  10. ↑ National Toxicology Program. (2012). NTP technical report on the photocarcinogenesis study of retinoic acid and retinyl palmitate [CAS Nos. 302-79-4 (All-trans-retinoic acid) and 79-81-2 (All-trans-retinyl palmitate)] in SKH-1 mice (Simulated solar light and topical application study). Available at http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/TR568_508.pdf. Accessed September 19, 2013.
  11. ↑ Safe vitamin A dosage during pregnancy and lactation (PDF), World Health Organization (WHO), 1998.
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