Chemistry of ascorbic acid: Difference between revisions

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| Name = {{sm|l}}-Ascorbic acid

| ImageFile = L-Ascorbic acid.svg

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| ImageFile1 = Ascorbic-acid-from-xtal-1997-3D-balls.png

| IUPACName = (5''R'')-[(1''S'')-1,2-Dihydroxyethyl]-3,4-dihydroxyfuran-2(5''H'')-one

| OtherNames = {{ubl|Vitamin C|{{sm|l}}-''threo''-Hex-2-enono-1,4-lactone}}

|Section1={{Chembox Identifiers

|Section2={{Chembox Properties

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'''Ascorbic acid''' is an [[organic compound]] with formula {{chem2|C6H8O6}}, originally called '''hexuronic acid'''. It is a white solid, but impure samples can appear yellowish.  It dissolves freely in water to give mildly acidic solutions.  It is a mild [[redox|reducing agent]].

Ascorbic acid exists as two [[enantiomer]]s (mirror-image [[isomer]]s), commonly denoted "{{sm|l}}" (for "levo") and "{{sm|d}}" (for "dextro"). The {{sm|l}} isomer is the one most often encountered: it occurs naturally in many foods, and is one form ("[[vitamer]]") of [[vitamin C]], an essential nutrient for humans and many animals.<ref name="Myers" /> Deficiency of vitamin C causes [[scurvy]], formerly a major disease of sailors in long sea voyages.<ref>{{cite news |title=Is scurvy making a comeback? |url=https://www.bbc.com/news/health-35380716 |work=[[BBC News]] |date=22 January 2016}}</ref> It is used as a [[food additive]] and a [[dietary supplement]] for its [[antioxidant]] properties. The "{{sm|d}}" form ([[erythorbic acid]]) can be made by chemical synthesis, but has no significant biological role.

The term ''ascorbic'' means antiscurvy and denotes the ability to fight off scurvy.<ref name="Myers">{{Cite book |last=Myers |first=Richard L. |url=https://books.google.com/books?id=0AnJU-hralEC |title=The 100 Most Important Chemical Compounds: A Reference Guide |date=2007 |publisher=ABC-CLIO |isbn=978-0-313-33758-1 |pages=30–32 |access-date=21 November 2015 |archive-date=17 June 2016 |archive-url=https://web.archive.org/web/20160617093705/https://books.google.com/books?id=0AnJU-hralEC |url-status=live }}</ref> It is related to combating Vitamin C deficiency.<ref>{{cite web |title=Ascorbic - Etymology, Origin & Meaning |url=https://www.etymonline.com/word/ascorbic |website=Etymonline}}</ref>

In 1933, sugar chemist [[Norman Haworth|Walter Norman Haworth]], working with samples of "hexuronic acid" that Szent-Györgyi had isolated from [[paprika]] and sent him in the previous year, deduced the correct structure and optical-isomeric nature of the compound, and in 1934 reported its first synthesis.<ref>[https://web.archive.org/web/20051113164634/http://profiles.nlm.nih.gov/WG/Views/Exhibit/narrative/szeged.html Story of Vitamin C's chemical discovery]. Profiles.nlm.nih.gov. Retrieved on 2012-12-04.</ref><ref>{{cite book | last1 = Davies  | first1 = Michael B.  | last2 = Austin  | first2 = John  | last3 = Partridge  | first3 = David A. | title = Vitamin C: Its Chemistry and Biochemistry  | publisher = The Royal Society of Chemistry  | year = 1991  | page = 48  | isbn = 0-85186-333-7}}

</ref> In reference to the compound's antiscorbutic properties, Haworth and Szent-Györgyi proposed to rename it "a-scorbic acid" for the compound, and later specifically {{sm|l}}-ascorbic acid.<ref>{{citation | first1 = Joseph Louis | last1 = Svirbelf | first2 = Albert | last2 = Szent-Györgyi | author-link2 = Albert Szent-Györgyi | url = https://profiles.nlm.nih.gov/WG/B/B/G/W/_/wgbbgw.pdf | archive-url = https://web.archive.org/web/20061011155513/http://profiles.nlm.nih.gov/WG/B/B/G/W/_/wgbbgw.pdf | url-status = dead | archive-date = October 11, 2006 | title = The Chemical Nature Of Vitamin C | journal = Science | volume = 75 | issue = 1944 | pages = 357–8 | date = April 25, 1932| bibcode = 1932Sci....75..357K | doi = 10.1126/science.75.1944.357-a | pmid = 17750032 | s2cid = 33277683 }}. Part of the [[National Library of Medicine]] collection. Accessed January 2007</ref>  Because of their work, in 1937 two [[Nobel Prize]]s: in Chemistry and in Physiology or Medicine were awarded to Haworth and Szent-Györgyi, respectively.

Aqueous solutions of dehydroascorbate are unstable, undergoing hydrolysis with a half-life of 5–15&nbsp;minutes at {{convert|37|C}}. Decomposition products include [[diketogulonic acid]], [[xylonic acid]], [[threonic acid]] and [[oxalic acid]].<ref>{{cite book |url=https://books.google.com/books?id=45I3EQAAQBAJ&q=diketogulonic&pg=PA311 |title = Ingredient Interactions: Effects on Food Quality, Second Edition|isbn = 9781420028133|last1 = Gaonkar|first1 = Anilkumar G.|last2 = McPherson|first2 = Andrew |date = 2016-04-19| publisher=CRC Press }}</ref><ref>{{cite journal |last1=Linster |first1=Carole L. |author-link1=:lb:Carole Linster |last2=Van Schaftingen |first2=Emile |title=Vitamin C: Biosynthesis, recycling and degradation in mammals |journal=The FEBS Journal |date=January 2007 |volume=274 |issue=1 |pages=1–22 |doi=10.1111/j.1742-4658.2006.05607.x|pmid=17222174 }}</ref>{{rp|p=14}}

The main use of {{sm|l}}-ascorbic acid and its salts is as food additives, mostly to combat oxidation and prevent discoloration of the product during storage.<ref>{{cite news |title=The Use of Ascorbic Acid as a Food Additive: Technical-Legal Issues |work=National Library of Medicine |date=2016 |publisher=National Center for Biotechnology Information|pmc=5076701 |volume=5 |issue=1 |page=4313 |doi=10.4081/ijfs.2016.4313 |pmid=27800425 | vauthors = Varvara M, Bozzo G, Celano G, Disanto C, Pagliarone CN, Celano GV }}</ref>  It is approved for this purpose in the EU with [[E number]] E300,<ref name="UK Food Standards Agency">UK Food Standards Agency: {{cite web |url=http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist |title=Current EU approved additives and their E Numbers |access-date=2011-10-27}}</ref> the US,<ref name="USFDA">US Food and Drug Administration: {{cite web|url=https://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/FoodAdditiveListings/ucm091048.htm |title=Listing of Food Additives Status Part I |website=[[Food and Drug Administration]] |access-date=2011-10-27 |url-status = dead|archive-url=https://web.archive.org/web/20120117060614/https://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/FoodAdditiveListings/ucm091048.htm |archive-date=2012-01-17 }}</ref> Australia, and New Zealand.<ref name="Australia New Zealand Food Standards Code-2011">Australia New Zealand Food Standards Code{{cite web |url=http://www.comlaw.gov.au/Details/F2011C00827 |title=Standard 1.2.4 – Labelling of ingredients |date=8 September 2011 |access-date=2011-10-27}}</ref>

Another major use of {{sm|l}}-ascorbic acid is as a [[dietary supplement]]. It is on the [[WHO Model List of Essential Medicines|World Health Organization's List of Essential Medicines]].<ref name="WHO-2023">{{cite book | vauthors = ((World Health Organization)) | title = The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023) | year = 2023 | hdl = 10665/371090 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | id = WHO/MHP/HPS/EML/2023.02 | hdl-access=free }}</ref><ref>{{cite web |title=World Health Organization Model list of essential medicines |url=https://iris.who.int/bitstream/handle/10665/371090/WHO-MHP-HPS-EML-2023.02-eng.pdf |publisher=World Health Organization}}</ref> Its deficiency over a prolonged period of time could cause scurvy, which is characterized by fatigue, widespread weakness in connective tissues and capillary fragility.<ref>{{cite web |title=Office of Dietary Supplements - Vitamin C |url=https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/ |website=ods.od.nih.gov |publisher=National Institute of Health |language=en}}</ref> It affects multiple organ systems due to its role in the biochemical reactions of connective tissue synthesis.<ref>{{cite journal |title=Scurvy: Rediscovering a Forgotten Disease |date=2023 |publisher=National Library of Medicine|pmc=10296835 |journal=Diseases |volume=11 |issue=2 |page=78 |doi=10.3390/diseases11020078 |doi-access=free |pmid=37366866 | vauthors = Gandhi M, Elfeky O, Ertugrul H, Chela HK, Daglilar E }}</ref> Ascorbic acid deficiency inhibits the body’s ability to synthesize collagen, which results in body deterioration such as producing tender joints, weakness, and ruptured blood vessels.<ref name="Myers" />

* In plastic manufacturing, ascorbic acid can be used to assemble molecular chains more quickly and with less waste than traditional synthesis methods.<ref>{{citation |title=Vitamin C, water have benefits for plastic manufacturing |url=http://reliableplant.com/article.asp?pagetitle=Vitamin%20C,%20water%20have%20benefits%20for%20plastic%20manufacturing&articleid=3133 |publisher=Reliable Plant Magazine |year=2007 |access-date=2007-06-25 |archive-url=https://web.archive.org/web/20070927230356/http://www.reliableplant.com/article.asp?pagetitle=Vitamin+C%2C+water+have+benefits+for+plastic+manufacturing&articleid=3133 |archive-date=2007-09-27 |url-status = dead}}</ref>

* Heroin users are known to use ascorbic acid as a means to convert heroin base to a water-soluble salt so that it can be injected.<ref>{{cite journal | vauthors = Beynon CM, McVeigh J, Chandler M, Wareing M, Bellis MA | title = The impact of citrate introduction at UK syringe exchange programmes: a retrospective cohort study in Cheshire and Merseyside, UK | journal = Harm Reduction Journal | volume = 4 | issue = 1 | pages = 21 | date = December 2007 | pmid = 18072971 | pmc = 2245922 | doi = 10.1186/1477-7517-4-21 | doi-access = free }}</ref>

* It is sometimes used as a urinary acidifier to enhance the antiseptic effect of [[methenamine]].<ref>{{cite journal|doi=10.1002/bdd.2510140106|title=Effect of urine pH and ascorbic acid on the rate of conversion of methenamine to formaldehyde|year=1993|last1=Strom|first1=J. Grady|last2=Jun|first2=H. Won|journal=Biopharmaceutics & Drug Disposition|volume=14|issue=1|pages=61–69|pmid=8427945|s2cid=11151179}}</ref><ref>{{cite journal|doi=10.1007/bf00545228|title=Effect of urinary acidifiers on formaldehyde concentration and efficacy with methenamine therapy|year=1982|last1=Nahata|first1=M. C.|last2=Cummins|first2=B. A.|last3=McLeod|first3=D. C.|last4=Schondelmeyer|first4=S. W.|last5=Butler|first5=R.|journal=European Journal of Clinical Pharmacology|volume=22|issue=3|pages=281–284|pmid=7106162|s2cid=31796137}}</ref><ref>{{cite journal |last1=Murphy |first1=Francis J. |last2=Zelman |first2=Samuel |title=Ascorbic Acid as a Urinary Acidifying Agent: 1. Comparison with the Ketogenic Effect of Fasting |url=https://www.auajournals.org/doi/abs/10.1016/S0022-5347%2817%2963619-X#:~:text=were%20determined%20incidentally.-,In%20doses%20of%200.5%20gm.,cal%2D%20cium%20in%20acid%20urine. |journal=The Journal of Urology |date=September 1965 |volume=94 |issue=3 |pages=297–299 |language=EN |doi=10.1016/S0022-5347(17)63619-X}}</ref>

A biotechnological process, first developed in China in the 1960s but further developed in the 1990s, bypasses acetone-protecting groups. A second [[genetically modified]] microbe species, such as mutant ''[[Erwinia]]'', among others, oxidises sorbose into 2-ketogluconic acid (2-KGA), which can then undergo ring-closing lactonization via dehydration. This method is used in the predominant process used by the ascorbic acid industry in China, which supplies 70% of the world's ascorbic acid.<ref name="Vantage Market Research-2022">{{cite press release |url=https://www.globenewswire.com/en/news-release/2022/11/08/2550571/0/en/Global-Vitamin-C-Market-Size-Share-to-Surpass-1-8-Bn-by-2028-China-Produces-80-of-Commercial-Vitamin-C-Vantage-Market-Research.html |title=Vantage Market Research: Global Vitamin C Market Size & Share to Surpass $1.8 Bn by 2028 |date=8 November 2022 |website=Globe Newswire |access-date=21 December 2023}}</ref> Researchers are exploring means for one-step fermentation.<ref>{{cite journal |vauthors=Zhou M, Bi Y, Ding M, Yuan Y |title=One-Step Biosynthesis of Vitamin C in Saccharomyces cerevisiae |journal=Front Microbiol |volume=12 |issue= |pages=643472 |date=2021 |pmid=33717042 |pmc=7947327 |doi=10.3389/fmicb.2021.643472 |url= |doi-access=free }}</ref><ref>{{cite journal |vauthors=Tian YS, Deng YD, Zhang WH, Yu-Wang, Xu J, Gao JJ, Bo-Wang, Fu XY, Han HJ, Li ZJ, Wang LJ, Peng RH, Yao QH |display-authors=5 |title=Metabolic engineering of Escherichia coli for direct production of vitamin C from D-glucose |journal=Biotechnol Biofuels Bioprod |volume=15 |issue=1 |pages=86 |date=August 2022 |pmid=35996146 |pmc=9396866 |doi=10.1186/s13068-022-02184-0 |url= |doi-access=free |bibcode=2022BBB....15...86T }}</ref>

* {{cite book | editor1-last = Gruenwald | editor1-first = J. | editor2-last = Brendler | editor2-first = T. | editor3-last = Jaenicke | editor3-first = C. | title = PDR for Herbal Medicines | url = https://archive.org/details/pdrforherbalmedi00joer_0 | url-access = registration | edition = 3rd | publisher = Thomson PDR | location = Montvale, New Jersey | year = 2004| isbn = 9781563635120 }}