On Air

Investment

Buy this Domain?
Do you interesting about this domain and the running project?
Feel free to send your offer to webmaster.
pay with Paypal

Advertising

Squalene

|Section2={{Chembox Properties | C=30 | H=50 | Appearance = Pale yellow, translucent liquid | Density = 0.858 g cm−3 | MeltingPtC = -5 | MeltingPt_ref = | BoilingPtC = 285 | BoilingPt_notes = at 3.3 kPa Merck Index, 11th Edition, 8727 | LogP = 12.188 | Viscosity = 12 cP (at 20 °C) }} |Section3={{Chembox Hazards | FlashPtC = 110 | NFPA-H= 1 | NFPA-F= 1 | NFPA-R= 0 }} }} Squalene is a natural 30-carbon organic compound originally obtained for commercial purposes primarily from shark liver oil (hence its name, as Squalus is a genus of sharks), although plant sources (primarily vegetable oils) are now used as well, including amaranth seed, rice bran, wheat germ, and olives. Yeast cells have been genetically engineered to produce commercially useful quantities of "synthetic" squalene. All plants and animals produce squalene as a biochemical intermediate, including humans. It occurs in high concentrations in the stomach oil of birds in the order Procellariiformes. Squalene is a hydrocarbon and a triterpene, and is a precursor for synthesis of all plant and animal sterols, including cholesterol and steroid hormones in the human body.

Role in steroid synthesis

Squalene is the biochemical precursor to the whole family of steroids. Oxidation (via squalene monooxygenase) of one of the terminal double bonds of squalene yields 2,3-squalene oxide, which undergoes enzyme-catalyzed cyclization to afford lanosterol, which is then elaborated into cholesterol and other steroids. Squalene is an ancient molecule. In plants, squalene is the precursor to stigmasterol. In certain fungi, it is the precursor to ergosterol. However, blue-green algae and some bacteria do not manufacture squalene, and must acquire it from the environment if they need it.

Biosynthesis

Interactive pathway map

Shark squalene

Squalene is a low density compound often stored in the bodies of cartilaginous fish such as sharks, which lack a swim bladder and must therefore reduce their body density with fats and oils. Squalene, which is stored mainly in the shark's liver, is lighter than water with a specific gravity of 0.855. Recently it has become a trend for sharks to be hunted to process their livers for the purpose of making squalene health capsules. Environmental and other concerns over shark hunting have motivated its extraction from vegetable sources EWG: Unilever takes a bite out of your face creamWolosik K1, Knas M, Zalewska A, Niczyporuk M, Przystupa AW. The importance and perspective of plant-based squalene in cosmetology. J Cosmet Sci. 2013 Jan-Feb;64(1):59-66. or biosynthetic processes instead.Spanova, Miroslava & Daum, Guenther. Squalene - biochemistry, molecular biology, process biotechnology, and applications. Eur. J. Lipid Sci. Technol. 2011,000, 0000–0000 DOI:10.1002/ejlt.201100203Biosynthesis of Squalene from Farnesyl Diphosphate in Bacteria: Three Steps Catalyzed by Three Enzymes. Jian-Jung Pan, Jose O. Solbiati, Gurusankar Ramamoorthy, Brandan S. Hillerich, Ronald D. Seidel, John E. Cronan, Steven C. Almo, and C. Dale Poulter. ACS Central Science 2015 1 (2), 77-82 DOI: 10.1021/acscentsci.5b00115

Derivative used as a skin moisturizer in cosmetics

Squalene is one of the most common lipids produced by human skin cells. It is a natural moisturizer, and occurs as a major component of nasal sebum. Squalane is a saturated form of squalene in which the double bonds have been eliminated by hydrogenation. Squalane is less susceptible to oxidation than squalene. Squalane is thus more commonly used than squalene in personal care products, such as moisturizers. Toxicology studies have determined that in the concentrations used in cosmetics, both squalene and squalane have low acute toxicity, and are not significant human skin irritants or sensitizers.

Use as an adjuvant in vaccines

Immunologic adjuvants are substances, administered in conjunction with a vaccine, that stimulate the immune system and increase the response to the vaccine. Squalene is not itself an adjuvant, but it has been used in conjunction with surfactants in certain adjuvant formulations. An adjuvant using squalene is Novartis' proprietary MF59, which is added to influenza vaccines to help stimulate the human body's immune response through production of CD4 memory cells. It is the first oil-in-water influenza vaccine adjuvant to be commercialized in combination with a seasonal influenza virus vaccine. It was developed in the 1990s by researchers at Ciba-Geigy and Chiron; both companies were subsequently acquired by Novartis. MF59 Adjuvant Fact Sheet, Novartis, June 2009. It is present in the form of an emulsion and is added to make the vaccine more immunogenic. Squalene-based adjuvants in vaccines, Global Advisory Committee on Vaccine Safety, World Health Organization However, the mechanism of action remains unknown. MF59 is capable of switching on a number of genes that partially overlap with those activated by other adjuvants. How these changes are triggered is unclear; to date, no receptors responding to MF59 have been identified. One possibility is that MF59 affects the cell behavior by changing the lipid metabolism, namely by inducing accumulation of neutral lipids within the target cells. An MF59-adjuvanted influenza vaccine (Fluad, developed by Chiron, which contains about 10 mg of squalene per dose) has been approved by health agencies and used in several European countries for seasonal flu shots since 1997.Andrew Pollack. Benefit and Doubt in Vaccine Additive, The New York Times, September 21, 2009. An influenza vaccine using MF59 as an adjuvant has been approved for use in the US in those 65 years of age and older, beginning with the 2016-2017 flu season.Centers for Disease Control and Prevention. linkhttps://www.cdc.gov/flu/protect/vaccine/adjuvant.htm, FLUAD™ Flu Vaccine With Adjuvant A 2009 meta-analysis assessed data from 64 clinical trials of influenza vaccines with the squalene-containing adjuvant MF59 and compared them to the effects of vaccines with no adjuvant. The analysis reported that the adjuvanted vaccines were associated with slightly lower risks of chronic diseases, but that neither type of vaccines altered the rate of autoimmune diseases; the authors concluded that their data "supports the good safety profile associated with MF59-adjuvanted influenza vaccines and suggests there may be a clinical benefit over non-MF59-containing vaccines".

Health controversies

There have been attempts to link squalene to Gulf War Syndrome mainly due to the idea that squalene might have been present in an anthrax vaccine given to some military personnel during the 1991 Persian Gulf War. Studies found that deployed Persian Gulf War Syndrome patients are significantly more likely to have antibodies to squalene (95 percent) than asymptomatic Gulf War veterans (0 percent; p A later study reported that about one in ten people have squalene antibodies in their blood, regardless of whether or not they received squalene from a vaccination. A later study confirmed this result, and also showed that vaccination with squalene-containing vaccines do not alter the levels of these naturally-occurring antibodies. A third study showed that these naturally-occurring antibodies were no more common in Gulf war veterans than in the general population. The squalene adjuvanted influenza vaccine that was given in Scandinavia and Europe in 2009 ( Pandemrix) could cause narcolepsy, a disorder of wakefulness. It was rare—just 1 in 15,000, or 1 in 50,000, depending on the country- but significant. An epidemiologic analysis of safety data on MF59 seasonal and pandemic influenza vaccines showed no evidence of increased risk of vaccine adverse events of potential autoimmune origin. The World Health Organization and the US Department of Defense have both published extensive reports that emphasize that squalene is a chemical naturally occurring in the human body, present even in oils of human fingerprints. WHO goes further to explain that squalene has been present in over 22 million flu vaccines given to patients in Europe since 1997 and there have never been significant vaccine-related adverse events.

References

External links

"green air" © 2007 - Ingo Malchow, Webdesign Neustrelitz
This article based upon the http://en.wikipedia.org/wiki/Squalene, the free encyclopaedia Wikipedia and is licensed under the GNU Free Documentation License.
Further informations available on the list of authors and history: http://en.wikipedia.org/w/index.php?title=Squalene&action=history
presented by: Ingo Malchow, Mirower Bogen 22, 17235 Neustrelitz, Germany