Some mammals have lost the ability to synthesize vitamin C, including simians and tarsiers , which together make up one of two major primate suborders, Haplorrhini. This group includes humans. The other more primitive primates Strepsirrhini have the ability to make vitamin C. Synthesis does not occur in most bats  nor in species in the rodent family Caviidae , that includes guinea pigs and capybaras , but does occur in other rodents, including rats and mice.
Reptiles and older orders of birds make ascorbic acid in their kidneys. Recent orders of birds and most mammals make ascorbic acid in their liver. Most tested families of bats order Chiroptera , including major insect and fruit-eating bat families, cannot synthesize vitamin C.
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A trace of gulonolactone oxidase was detected in only 1 of 34 bat species tested, across the range of 6 families of bats tested. Some of these species including humans are able to make do with the lower levels available from their diets by recycling oxidised vitamin C. Most simians consume the vitamin in amounts 10 to 20 times higher than that recommended by governments for humans.
It is countered by arguments that humans are very good at conserving dietary vitamin C, and are able to maintain blood levels of vitamin C comparable with simians on a far smaller dietary intake, perhaps by recycling oxidized vitamin C. There are many different biosynthesis pathways for ascorbic acid in plants. Most of these pathways are derived from products found in glycolysis and other pathways. For example, one pathway goes through the plant cell wall polymers.
All plants synthesize ascorbic acid.
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Ascorbic acid functions as a cofactor for enzymes involved in photosynthesis, synthesis of plant hormones, as an antioxidant and also regenerator of other antioxidants. The major pathway starts with glucose, fructose or mannose all simple sugars and proceeds to L- galactose , L-galactonolactone and ascorbic acid. Ascorbic acid is a common enzymatic cofactor in mammals used in the synthesis of collagen , as well as a powerful reducing agent capable of rapidly scavenging a number of reactive oxygen species ROS.
Given that ascorbate has these important functions, it is surprising that the ability to synthesize this molecule has not always been conserved. In fact, anthropoid primates, Cavia porcellus guinea pigs , teleost fishes, most bats, and some Passeriform birds have all independently lost the ability to internally synthesize Vitamin C in either the kidney or the liver.
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In the case of the simians, it is thought that the loss of the ability to make vitamin C may have occurred much farther back in evolutionary history than the emergence of humans or even apes, since it evidently occurred soon after the appearance of the first primates, yet sometime after the split of early primates into the two major suborders Haplorrhini which cannot make vitamin C and its sister suborder of non-tarsier prosimians, the Strepsirrhini "wet-nosed" primates , which retained the ability to make vitamin C.
It has also been noted that the loss of the ability to synthesize ascorbate strikingly parallels the inability to break down uric acid , also a characteristic of primates. Uric acid and ascorbate are both strong reducing agents. This has led to the suggestion that, in higher primates, uric acid has taken over some of the functions of ascorbate. Vitamin C is produced from glucose by two main routes.
The Reichstein process , developed in the s, uses a single pre-fermentation followed by a purely chemical route. The modern two-step fermentation process, originally developed in China in the s, uses additional fermentation to replace part of the later chemical stages. The Reichstein process and the modern two-step fermentation processes use sorbitol as the starting material and convert it to sorbose using fermentation.
The modern two-step fermentation process then converts sorbose to 2-keto-l-gulonic acid KGA through another fermentation step, avoiding an extra intermediate. The need to include fresh plant food or raw animal flesh in the diet to prevent disease was known from ancient times. Native people living in marginal areas incorporated this into their medicinal lore. For example, spruce needles were used in temperate zones in infusions, or the leaves from species of drought-resistant trees in desert areas. In , the French explorer Jacques Cartier , exploring the St.
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Lawrence River , used the local natives' knowledge to save his men who were dying of scurvy. In the expedition of Vasco da Gama , the curative effects of citrus fruit were known. Authorities occasionally recommended plant food to prevent scurvy during long sea voyages. John Woodall , the first surgeon to the British East India Company , recommended the preventive and curative use of lemon juice in his book, The Surgeon's Mate. Scurvy had long been a principal killer of sailors during the long sea voyages.
The first attempt to give scientific basis for the cause of this disease was by a ship's surgeon in the Royal Navy , James Lind. While at sea in May , Lind provided some crew members with two oranges and one lemon per day, in addition to normal rations, while others continued on cider , vinegar , sulfuric acid or seawater , along with their normal rations, in one of the world's first controlled experiments.
Lind published his work in in his Treatise on the Scurvy. Fresh fruit was expensive to keep on board, whereas boiling it down to juice allowed easy storage but destroyed the vitamin especially if boiled in copper kettles. In , ships in the West Indies were provided with lime juice instead, and in lime juice was used throughout the Royal Navy, giving rise to the American use of the nickname "limey" for the British.
The name antiscorbutic was used in the eighteenth and nineteenth centuries for foods known to prevent scurvy. These foods included lemons, limes, oranges, sauerkraut, cabbage, malt , and portable soup. Vitamin C was discovered in , isolated in and synthesized in , making it the first vitamin to be synthesized. In Hoffmann—La Roche trademarked synthetic vitamin C under the brand name Redoxon  and began to market it as a dietary supplement. By luck, this species did not make its own vitamin C, whereas mice and rats do. One of these was thought to be the anti-scorbutic factor.
In , this was referred to as "water-soluble C," although its chemical structure had not been determined. Svirbely 's Hungarian team, and Charles Glen King 's American team, identified the anti-scorbutic factor.
Methods for the Determination of Vitamins in Food
This led to a bitter dispute over priority. In , J. Burns showed that some mammals are susceptible to scurvy as their liver does not produce the enzyme l -gulonolactone oxidase , the last of the chain of four enzymes that synthesize vitamin C. He later developed the theory that humans possess a mutated form of the l -gulonolactone oxidase coding gene. In , researchers at the University of Montpellier discovered that in humans and other primates the red blood cells have evolved a mechanism to more efficiently utilize the vitamin C present in the body by recycling oxidized l -dehydroascorbic acid DHA back into ascorbic acid for reuse by the body.
The mechanism was not found to be present in mammals that synthesize their own vitamin C. Vitamin C megadosage is a term describing the consumption or injection of vitamin C in doses comparable to or higher than the amounts produced by the livers of mammals which are able to synthesize vitamin C.
The theory behind this, although not the actual term, was described in in an article by Linus Pauling. The recommendation also fell into the consumption range for gorillas - a non-synthesizing near-relative to humans. Pauling popularized the concept of high dose vitamin C as prevention and treatment of the common cold in The mega-dosing theory is to a large degree discredited.
Modest benefits are demonstrated for the common cold. In February , the Swiss Post issued a postage stamp bearing a depiction of a model of a molecule of vitamin C to mark the International Year of Chemistry. From Wikipedia, the free encyclopedia. For other uses, see vitamin C disambiguation. A11G WHO. OTC when used by mouth ; prescription for injectable form. IUPAC name.
Interactive image. Main article: Scurvy. Further information: Vitamin C and the common cold. See also: Chemistry of ascorbic acid. This section needs expansion with: the content specified on the talk page.
profcesliveabport.ml You can help by adding to it. Relevant discussion may be found on Talk:Vitamin C. December Further information: Ascorbic acid molecular aspects. Further information: Vitamin C megadosage. Plant embryos efflux high amounts of ascorbate that chemically reduce iron III from ferric complexes. Archived from the original on December 30, Retrieved December 8, Archived from the original on September 2, Retrieved September 1, July 1, Retrieved June 19, February 11, Archived from the original on July 30, World Health Organization.
Archived PDF from the original on December 13, Bibcode : PLoSO Archived from the original on December 31, Retrieved December 30, April Pharmaceutical Press. Vitamin C: Supplier Prices".