A white, crystalline vitamin, C6H8O6, found in citrus fruits, tomatoes, potatoes, and leafy green vegetables and used to prevent scurvy. Also called vitamin C.
[A-1 + SCORB(UT)IC.]
ascorbic acid
Dictionary:
a·scor·bic acid (ə-skôr'bĭk)  |
n.
A white, crystalline vitamin, C6H8O6, found in citrus fruits, tomatoes, potatoes, and leafy green vegetables and used to prevent scurvy. Also called vitamin C.
A white, crystalline vitamin, C6H8O6, found in citrus fruits, tomatoes, potatoes, and leafy green vegetables and used to prevent scurvy. Also called vitamin C.
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| Sci-Tech Encyclopedia: Ascorbic acid |
A white, crystalline compound, also known as vitamin C. It is highly soluble in water, which is a stronger reducing agent than the hexose sugars, which it resembles chemically. Vitamin C deficiency in humans has been known for centuries as scurvy. The compound has the structural formula shown below.
The stability of ascorbic acid decreases with increases in temperature and pH. This destruction by oxidation is a serious problem in that a considerable quantity of the vitamin C content of foods is lost during processing, storage, and preparation.
While vitamin C is widespread in plant materials, it is found sparingly in animal tissues. Of all the animals studied, only a few, including humans, require a dietary source of vitamin C. The other species are capable of synthesizing the vitamin in such tissues as liver and kidneys. Some drugs, particularly the terpene-like cyclic ketones, stimulate the production of ascorbic acid by rat tissues.
Vitamin C–deficient animals suffer from defects in their mesenchymal tissues. Their ability to manufacture collagen, dentine, and osteoid, the intercellular cement substances, is impaired. This may be related to a role of ascorbic acid in the formation of hydroxy-proline, an amino acid found in structural proteins, particularly collagen. People with scurvy lose weight and are easily fatigued. Their bones are fragile, and their joints sore and swollen. Their gums are swollen and bloody, and in advanced stages their teeth fall out. They also develop internal and subcutaneous hemorrhages.
There is evidence that vitamin C may play roles in stress reactions, in infectious disease, or in wound healing. Therefore, many nutritionists believe that the human intake of ascorbic acid should be many times more than that intake level which produces deficiency symptoms. The recommended dietary allowances of the Food and Nutrition Board of the National Research Council are 30 mg per day for 1- to 3-month infants, 80 mg per day for growing boys and girls, and 100 mg per day for pregnant and lactating women. These values represent an intake which tends to maintain tissue and plasma concentrations in a range similar to that of other well-nourished species of animals.
| Food and Nutrition: ascorbic acid |
Vitamin C, chemically l-xyloascorbic acid, to distinguish it from the isomer d-araboascorbic acid (isoascorbic acid or erythorbic acid), which has only slight vitamin C activity. Both ascorbic acid and erythorbic acid have strong chemical-reducing properties, and are used as antioxidants in foods and to preserve the red colour of fresh and preserved meats, and in the curing of hams.
[as-KOHR-bihk] The scientific name for vitamin C, ascorbic acid is sold for home use to prevent browning of vegetables and fruits. It's used in commercial preparations as an antioxidant.
| Dental Dictionary: ascorbic acid |
n
vitamin C
trade name: generic; many brand names; drug class: vitamin C, water-soluble vitamin; action: needed for wound healing, collagen synthesis, antioxidant, carbohydrate metabolism; uses: vitamin C deficiency, scurvy, delayed wound and bone healing, chronic disease, urine acidification, before gastrectomy.
| Drug Info: Ascorbic Acid, Vitamin C |
Brand names: Acerola®Acerola® CAll Day® C CRAsco-Caps-1000Asco-Caps-500Asco-Tabs-1000Ascocid®Ascocid®-1000Ascocid®-500Ascor L 500®Betac®C-Time™Cecon®Cemill® 1000Cemill® 500Cenolate™Cenolate®Cevi-Bid®Chew-CFruity C®Mega C/A Plus™Ortho CS™Strawberry C®Sunkist® Vitamin CVicks® Vitamin C Drops
Chemical formula:
- Drug Forms:
- Ascorbic Acid (Vitamin C) Oral tablet (below)
- Ascorbate (Vitamin C) Chewable tablet
- Ascorbic Acid (Vitamin C) Chewable tablet
- Ascorbic Acid (Vitamin C) Oral capsule, extended-release
- Ascorbic Acid (Vitamin C) Oral solution
- Ascorbic Acid (Vitamin C) Oral tablet, extended-release
- Español:
- Ácido Ascórbico (Vitamina C), Tableta oral
- Ascorbato (Vitamina C), Tableta masticable
- Ácido Ascórbico (Vitamina C), Tableta masticable
- Ácido Ascórbico (Vitamina C), Cápsula oral de liberación prolongada
- Ácido Ascórbico (Vitamina C), Solución oral
- Ácido Ascórbico (Vitamina C), Tableta oral de liberación prolongada
Ascorbic Acid (Vitamin C) Oral tablet
What is this medicine?
ASCORBIC ACID is a naturally occurring form of vitamin C. It is used to treat or prevent low levels of vitamin C and to treat scurvy.
This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of the following conditions:
•anemia
•diabetes
•glucose-6-phosphate dehydrogenase (G6PD) deficiency
•kidney stones
•low sodium diet
•an unusual or allergic reaction to ascorbic acid, tartrazine, other medicines, foods, dyes, or preservatives
•pregnant or trying to get pregnant
•breast-feeding
How should I use this medicine?
Take this medicine by mouth with a glass of water. Follow the directions on the package or prescription label. You may take this medicine with or without food. If it upsets your stomach take it with food. Take your medicine at regular intervals. Do not take your medicine more often than directed.
Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for selected conditions, precautions do apply.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What may interact with this medicine?
•deferoxamine
•iron supplements
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medicine?
Follow a good diet. Taking a vitamin supplement does not replace the need for a balanced diet. Some foods that have vitamin C naturally are citrus fruits, green peppers, broccoli, cabbage, and tomatoes.
If you are diabetic very high doses of ascorbic acid can interfere with tests for sugar in the urine. Talk to your doctor or heath care professional if you check your urine glucose levels.
What side effects may I notice from receiving this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
•allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
•breathing problems
•diarrhea with headache or nausea
•flushing or redness of skin
•pain in lower back, side, or stomach
Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
•bad taste in the mouth
•stomach upset
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medicine?
Keep out of the reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F) or as directed on the package label. Protect from heat and moisture. Throw away any unused medicine after the expiration date.
Last updated: 7/1/2002
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
| Wine Lover's Companion: ascorbic acid |
Known commonly as vitamin C, ascorbic acid is used in winemaking primarily as an antioxidant.
| Health Dictionary: ascorbic acid |
| Wikipedia: Ascorbic acid |
This article is about the molecular aspects of ascorbic acid. For information about its role in nutrition, see Vitamin C.
| L-Ascorbic acid | |
|---|---|
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 |
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| IUPAC name |
(5R)-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one
|
| Other names | Vitamin C |
| Identifiers | |
| CAS number | 50-81-7  |
| PubChem | 5785 |
| EC number | 200-066-2 |
| ATC code | A11 |
| SMILES |
OC=1C(OC(=O)C=1O)[C@@H](O)CO
|
| InChI |
1/C6H8O6/c7-1-2(8)5-3(9)4(10)6(11)12-5/h2,5,7-10H,1H2/t2-,5?/m0/s1
|
| InChI key | CIWBSHSKHKDKBQ-SZSCBOSDBY |
| ChemSpider ID | 17206850 |
| Properties | |
| Molecular formula | C6H8O6 |
| Molar mass | 176.12 g mol−1 |
| Appearance | White or light yellow solid |
| Density | 1.65 g/cm3 |
| Melting point |
190-192 °C, 463-465 K, 374-378 °F (decomp.) |
| Solubility in water | 33 g/100 ml |
| Solubility in ethanol | 2 g/100 ml |
| Solubility in glycerol | 1 g/100 ml |
| Solubility in propylene glycol | 5 g/100 ml |
| Solubility in [[{{{Solvent4}}}]] | insoluble in diethyl ether, chloroform, benzene, petroleum ether, oils, fats, fat solvents |
| Acidity (pKa) | 4.17 (first), 11.6 (second) |
| Hazards | |
| MSDS | External MSDS |
| LD50 | 11.9 g/kg (oral, rat)[1] |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Ascorbic acid is a sugar acid with antioxidant properties. Its appearance is white to light-yellow crystals or powder, and it is water-soluble. One form of ascorbic acid is commonly known as vitamin C. The name is derived from a- (meaning "no") and scorbutus (scurvy), the disease caused by a deficiency of vitamin C. In 1937 the Nobel Prize for chemistry was awarded to Walter Haworth for his work in determining the structure of ascorbic acid (shared with Paul Karrer, who received his award for work on vitamins), and the prize for Physiology or Medicine that year went to Albert Szent-Györgyi for his studies of the biological functions of L-ascorbic acid. At the time of its discovery in the 1920s, it was called hexuronic acid by some researchers.[2]
Contents |
Chemistry
Acidity
Ascorbic acid, the formula of which is C6H8O6, behaves as a vinylogous carboxylic acid, wherein the double bond ("vinyl") transmits electron pairs between the hydroxyl and the carbonyl. There are two resonance structures for the deprotonated form, differing in the position of the double bond.
Another way to look at ascorbic acid is to consider it as an enol. The deprotonated form is an enolate, which is usually strongly basic. However, the adjacent double bond stabilizes the deprotonated form.
Tautomerism
Nucleophilic attack of ascorbic enol on proton to give 1,3-diketone
Ascorbic acid also interconverts into two unstable diketone tautomers by proton transfer, although it is the most stable in the enol form. The proton of the enol is lost, and reacquired by electrons from the double bond, to produce a diketone. This is an enol reaction. There are two possible forms: 1,2-diketone and 1,3-diketone.
Determination
The concentration of a solution of ascorbic acid can be determined in many ways, the most common ways involving titration with an oxidizing agent.
- Iodine
Another method involves using iodine and a starch indicator, wherein iodine reacts with ascorbic acid, and, when all the ascorbic acid has reacted, the iodine is then in excess, forming a blue-black complex with the starch indicator. This indicates the end-point of the titration. As an alternative, ascorbic acid can be reacted with iodine in excess, followed by back titration with sodium thiosulfate while using starch as an indicator.
- Iodate and iodine
The above method involving iodine requires making up and standardising the iodine solution. One way around this is to generate the iodine in the presence of the ascorbic acid by the reaction of iodate and iodide ion in acid solution.
- N-Bromosuccinimide
A much-less-common oxidising agent is N-bromosuccinimide, (NBS). In this titration, the NBS oxidises the ascorbic acid (in the presence of potassium iodide and starch). When the NBS is in excess (i.e., the reaction is complete), the NBS liberates the iodine from the potassium iodide, which then forms the blue/black complex with starch, indicating the end-point of the titration.
Uses
 |
 |
Top: ascorbic acid
(reduced form of Vitamin C)
Bottom: dehydroascorbic acid
(oxidized form of Vitamin C)
(reduced form of Vitamin C)
Bottom: dehydroascorbic acid
(oxidized form of Vitamin C)
Ascorbic acid is easily oxidized and so is used as a reductant in photographic developer solutions (among others) and as a preservative.
Exposure to oxygen, metals, light, or heat destroys ascorbic acid, so it must be stored in a dark, cold, and non-metallic container.
The L-enantiomer of ascorbic acid is also known as vitamin C. The name "ascorbic" comes from its property of preventing and curing scurvy. Primates, including humans, and a few other species in all divisions of the animal kingdom, notably the guinea pig, have lost the ability to synthesize ascorbic acid, and must obtain it in their food.
Ascorbic acid and its sodium, potassium, and calcium salts are commonly used as antioxidant food additives. These compounds are water-soluble and thus cannot protect fats from oxidation: For this purpose, the fat-soluble esters of ascorbic acid with long-chain fatty acids (ascorbyl palmitate or ascorbyl stearate) can be used as food antioxidants. Eighty percent of the world's supply of ascorbic acid is produced in China. [3]
The relevant European food additive E numbers are
- E300 ascorbic acid,
- E301 sodium ascorbate,
- E302 calcium ascorbate,
- E303 potassium ascorbate,
- E304 fatty acid esters of ascorbic acid (i) ascorbyl palmitate (ii) ascorbyl stearate.
In plastic manufacturing, ascorbic acid can be used to assemble molecular chains more quickly and with less waste than traditional synthesis methods.[4]
Antioxidant mechanism
Ascorbate acts as an antioxidant by being available for energetically favourable oxidation. Many oxidants (typically, reactive oxygen species) such as the hydroxyl radical (formed from hydrogen peroxide), contain an unpaired electron, and, thus, are highly reactive and damaging to humans and plants at the molecular level. This is due to their interaction with nucleic acid, proteins, and lipids. Reactive oxygen species oxidize (take electrons from) ascorbate first to monodehydroascorbate and then dehydroascorbate. The reactive oxygen species are reduced to water, while the oxidized forms of ascorbate are relatively stable and unreactive, and do not cause cellular damage.
Ascorbic acid synthesis in non-primates
Ascorbic acid is found in plants, animals, and single-cell organisms.[5] All living animals either make it, eat it, or die from scurvy due to lack of it. Reptiles and older orders of birds make ascorbic acid in their kidneys. Recent orders of birds and most mammals make ascorbic acid in their livers where the enzyme L-gulonolactone oxidase is required to convert glucose to ascorbic acid.[5] Humans, guinea pigs, and some other primates are not able to make L-gulonolactone oxidase because of a genetic mutation and are therefore unable to make ascorbic acid in their livers. This genetic mutation occurred about 63 million years ago [5] This would have had lethal consequences for the mutated primate were it not for the fact that it occurred to an arboreal animal living in a tropical environment where plenty of foodstuffs containing ascorbic acid were available throughout the year. Although ascorbic acid is a vital food nutrient for humans and is therefore termed a vitamin, it is a natural liver metabolite in most other animals. Synthesis and signalling properties are still under investigation[6].
See also
- Colour retention agent
- Vitamin C: a discussion of the medical properties of ascorbic acid as well as its historic and social role
- Dehydroascorbic acid, an oxidized form of ascorbic acid.
- Erythorbic acid: a diastereomer of ascorbic acid.
- Mineral ascorbates: salts of ascorbic acid
- D-erythroascorbic acid: yeasts do not make vitamin C (L-ascorbic acid), but a similar antioxidant known as D-erythroascorbic acid
- Acids in wine
- Evolution of Vitamin C
References
- ^ "Safety (MSDS) data for ascorbic acid". Oxford University. 2005-10-09. http://physchem.ox.ac.uk/MSDS/AS/ascorbic_acid.html. Retrieved 2007-02-21.
- ^ Svirbelf, Joseph Louis; Szent-Gyorgyi, Albert (April 25, 1932), The Chemical Nature Of Vitamin C, http://profiles.nlm.nih.gov/WG/B/B/G/W/_/wgbbgw.pdf. Part of the National Library of Medicine collection. Accessed January 2007
- ^ "Tainted Chinese Imports Common", Washington Post, May 20, 2007, http://www.washingtonpost.com/wp-dyn/content/article/2007/05/19/AR2007051901273.html.
- ^ Vitamin C, water have benefits for plastic manufacturing, Reliable Plant Magazine, 2007, http://reliableplant.com/article.asp?pagetitle=Vitamin%20C,%20water%20have%20benefits%20for%20plastic%20manufacturing&articleid=3133, retrieved 2007-06-25.
- ^ a b c Stone, Irwin (1972), The Natural History of Ascorbic Acid in the Evolution of Mammals and Primates, http://www.seanet.com/~alexs/ascorbate/197x/stone-i-orthomol_psych-1972-v1-n2-3-p82.htm.
- ^ Valpuesta, Victoriano; Botella, Miguel (December 2004), "Biosynthesis of L-ascorbic acid in plants: new pathways for an old antioxidant", TRENDS in Plant Science 9 (12), http://www.bmbq.uma.es/lbbv/index_archivos/pdf/Valpuesta%202004.pdf
Further reading
- Clayden; Greeves; Warren; Wothers (2001), Organic Chemistry, Oxford University Press, ISBN 0-19-850346-6.
- Davies, Michael B.; Austin, John; Partridge, David A., Vitamin C: Its Chemistry and Biochemistry, Royal Society of Chemistry, ISBN 0-85186-333-7.
- Coultate, T. P., Food: The Chemistry of Its Components (3rd ed.), Royal Society of Chemistry, ISBN 0-85404-513-9.
- Gruenwald, J.; Brendler, T.; Jaenicke, C., eds. (2004), PDR for Herbal Medicines (3rd ed.), Montvale, NJ: Thomson PDR.
External links
- International Chemical Safety Card 0379
- SIDS Initial Assessment Report for L-Ascorbic acid from the Organisation for Economic Co-operation and Development (OECD)
- IPCS Poisons Information Monograph (PIM) 046
- Safety data from the University of Oxford.
- The Effect of Ascorbic Acid on Bleaching Coral
- The Effect of Ascorbic Acid on Fragmented Coral
- Interactive 3D-structure of vitamin C with details on the x-ray structure
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Related answers
- What has ascorbic acid in it?
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