ASCORBIC ACID FINE (ASKORBK AST NCE TOZ)
ASCORBIC ACID FINE
SYNONYMS: (R)-5-((S)-1,2-Dihydroxyethyl)-3,4-dihydroxyfuran-2(5H)-one; L-ascorbic acid; L-Threoascorbic acid,Antiscorbutic factor,Vitamin C; L-Ascorbic acid（C); L-Ascorbic acid; 1-(4-phenethylpiperazin-1-yl)-2-(1-phenylcyclohexyl)ethanone ascorbate; 1-(4-phenethylpiperazin-1-yl)-2-(1-phenylcyclohexyl)ethanone ascorbate; l-ascorbic acid, ascorbic acid, vitamin c, l-ascorbate, ascorbate, ascorbicap, l +-ascorbic acid, cevitamic acid, ascoltin, hybrin; (2R)-2-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2H-furan-5-one; 3-O-Ethyl Ascorbic Acid; Ethyl Ascorbic Acid; L(+)-ascorbate; L-(+)-ascorbate; L-(+)-ascorbic acid; l(+)-ascorbic acid standard; l,3-ketothreohexuronic acid; Laroscorbine; L-ascorbate; L-Ascorbate;Vitamin C; L-ASCORBIC ACID 2-(DIHYDROGEN PHOSPHATE); l-ascorbic acid (vitamin c); L-ASCORBIC ACID-6,6-D2; l-ascorbic acid; Lemascorb; Liqui-Cee; L-lyxoascorbate; L-Lyxoascorbic acid; L-threo-Ascorbic acid; L-threo-hex-2-enono-1,4-lactone; L-xyloascorbate; L-XYLOASCORBIC ACID; meilun; Meri-C; Natrascorb; Natrascorb injectable; Planavit C; Proscorbin; Redoxon; Ronotec 100; Rontex 100; Roscorbic; Rovimix C; Scorbacid; Scorbu C; Scorbu-C; Secorbate; Semidehydroascorbate; Semidehydroascorbic acid; Suncoat VC 40; Testascorbic; Vasc; Vicelat; Vicin; Vicomin C; Viforcit; Viscorin; Vitace; Vitacee; Vitacimin; Vitacin; Vitamisin; Vitascorbol; Xitix; γ-lactone L-threo-Hex-2-enonate; γ-lactone L-threo-Hex-2-enonic acid; 维生素c; century, hundred, light speed, degree Celsius, nose candy, snow, coke, vitamin C, deoxycytidine monophosphate, one C, degree centigrade, ampere-second, coulomb, speed of light, atomic number 6, blow, carbon, cytosine; vitamin C, E300, hexuronic acid; l-ascorbic acid; ascorbic acid; vitamin C; 50-81-7; L(+)-Ascorbic acid; Ascorbicap; Cevitamic acid; L-ascorbate; ascorbate; Ascoltin; Hybrin; Allercorb; Ascorbajen; Ascorbutina; Ascorteal; Cescorbat; Cetemican; Cevitamin; Citriscorb; Laroscorbine; Lemascorb; Natrascorb; Proscorbin; Roscorbic; Secorbate; Testascorbic; Vitacimin; Vitamisin; Vitascorbol; Ascorin; Ascorvit; Cantaxin; Cebicure; Cebione; Cegiolan; Ceglion; Celaskon; Cemagyl; Cenetone; Cenolate; Cergona; Cetamid; Cevalin; Cevatine; Cevimin; Cevital; Cevitan; Cevitex; Colascor; Concemin; Redoxon; Vicelat; Viforcit; Viscorin; Vitacee; Vitacin; Adenex; Ascorb; Cantan; Cebid; Cebion; Cecon; Celin; Cemill; Cereon; Cevex; Ciamin; Cipca; Hicee; Ribena; Vitace; Xitix; Davitamon C; Arco-cee; Planavit C; Catavin C; Ce lent; Liqui-Cee; Vicomin C; Cee-Vite; Cevi-Bid; Scorbu-C; C-Level; C-Vimin; Cetane-Caps TD; Duoscorb; Scorbacid; Cewin; Antiscorbic vitamin; C-Quin; C-Span; Meri-C; Cee-Caps TD; L-Lyxoascorbic acid; L-Xyloascorbic acid; Antiscorbutic vitamin; Cetane-Caps TC; Acidum ascorbinicum; 3-Oxo-L-gulofuranolactone; Ce-Mi-Lin; IDO-C; Natrascorb injectable; Acidum ascorbicum; L-(+)-Ascorbic Acid; CE-VI-Sol; Ferrous ascorbate; Ascor-B.I.D.; Acido ascorbico; Acide ascorbique; Dora-C-500; Kyselina askorbova; 3-Keto-L-gulofuranolactone; Ascorbicab; Cortalex; Ferancee; Stuartinic; Tolfrinic; Antiscorbutic factor; L-3-Ketothreohexuronic acid lactone; L-Threoascorbic acid; Chromagen; Cetebe; Kyselina askorbova; Caswell No. 061B; Vicin; Acide ascorbique; Acido ascorbico; Acidum ascorbicum; Sodascorbate; Ascorbicin; (R)-5-((S)-1,2-dihydroxyethyl)-3,4-dihydroxyfuran-2(5H)-one; NCI-C54808; L-threo-Hex-2-enonic acid, gamma-lactone; 3-Oxo-L-gulofuranolactone; UNII-PQ6CK8PD0R; CCRIS 57; MFCD00064328; Ascorbin; FEMA No. 2109; HSDB 818; Hex-2-enonic acid gamma-lactone, L-threo-; EINECS 200-066-2; NSC 33832; Iron(II) ascorbate; PQ6CK8PD0R; L-threo-Ascorbic acid; component of E and C-Level; component of Endoglobin Forte; CHEBI:29073; (+)-Ascorbic acid; component of Cortalex; component of Ferancee; NCGC00164357-01; E300; Magnorbin; (2R)-2-[(1S)-1,2-dihydroxyethyl]-4,5-dihydroxyfuran-3-one; (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one; DSSTox_CID_106; Iron-ascorbic acid complexes; DSSTox_RID_75370; Ascorbinsaure; DSSTox_GSID_20106; Kangbingfeng; Chewcee; Citrovit; Juvamine; Ceklin; Magnesium Ascorbicum; Vasc; L(+)-Ascorbic acid, 99%; (+)-Sodium L-ascorbate; Rovimix C; Scorbu C; cevibid; Ascorbinsaeure; Parentrovite; Sunkist; Ascorbic Acid, Monosodium Salt; Cell C; L(+)-Ascorbic acid, ACS reagent; roscorbi c; Acid Ascorbic; Viscorin 100M; (2R)-2-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2H-furan-5-one; 1-Xyloascorbic Acid; Ronotec 100; Suncoat VC 40; (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2,5-dihydrofuran-2-one; Oral Vitamin C; Rontex 100; ascor-b.i.d; Ascorbicap (TN); Xyloascorbic acid, L-; Ascoltin (TN); L-Threoascorbic acid; Antiscorbutic factor; Vitamin C; (R)-5-((S)-1,2-Dihydroxyethyl)-3,4-dihydroxyfuran-2(5H)-one; antiscorbic vita min; [14C]ascorbic acid; Ascorbic acid; Ascorbicacid; [14C]-ascorbic acid; 3-Keto-1-Gulofuranolactone; ascorbic acid (vit C); L-Ascorbic acid; 299-36-5; L-3-ketothreohexuronic acid; Cevitamate; Ascor; L-lyxoascorbate; L-xyloascorbate; Ascorbinsaure; L-AscorbicAcid; Vitamin B mixture with vitamin C; 3eka; cee-caps td; Ester C; Ester-C; Sodium Ascorbate (Ascorbic Acid); (+)-ascorbate; L(+)-ascorbate; L-threo-hex-2-enono-1,4-lactone; AK-96407; L-Ascorbic acid, free radical form; L-(+)-ascorbate; Ascorbic acid; Ascorbic acid mixture with Vitamin B; Vitamin C,(S); E 300; PubChem18445; vitamin-c-ascorbic-acid; Ascorbic Acid DC97SF; Prestwick3_000325; L-Ascorbic acid, 99%; Ascorbic Acid mixture with Vitamin B Complex; SCHEMBL785; bmse000182; Vitamin C (Ascorbic acid); AC1L1L4T; SCHEMBL4430; L-Ascorbic acid, FCC, FG; BSPBio_000329; KSC925A7P; MLS002153776; CHEMBL40274; AC1Q77S6; BPBio1_000363; GTPL4532; GTPL4781; L-Ascorbic acid, reagent grade; DTXSID5020106; L-Ascorbic acid, >=99.0%; CTK8C5077; BIA0602; Ascorbic acid; CIWBSHSKHKDKBQ-JLAZNSOCSA-N; ZX-AFC000785; HMS2096A11; HMS2231N16; HMS3713A11; (2R)-2-[(1S)-1,2-Dihydroxyethyl]-4,5-dihydroxy-furan-3-one; 89924-69-6; BCP27915; HY-B0166; KS-00000EU9; Tox21_110315; Tox21_112104; Tox21_202127; Tox21_302958; ANW-73969; gamma-lactone L-threo-Hex-2-enonate; L-Ascorbic acid, analytical standard; L-Ascorbic acid, AR, >=99.5%; LS-145; s3114; AKOS016843589; Tox21_112104_1; ZINC100006770; ZINC100019304; CCG-207946; DB00126; FCH1121413; L-Ascorbic acid, mixt. with vitamin B; RP23765; RTR-032643; VIT0000113; gamma-lactone L-threo-Hex-2-enonic acid; L-Ascorbic acid, ACS reagent, >=99%; NCGC00091517-01; NCGC00091517-02; NCGC00091517-03; NCGC00091517-06; NCGC00188972-01; NCGC00256504-01; NCGC00259676-01; 53262-66-1; BP-12831; SC-18563; SMR001233160; L-Ascorbic acid, plant cell culture tested; AB0010512; AB1002440; AX8021086; L-Ascorbic acid, reagent grade, crystalline; A0537; A8158; AB00376923; Ascorbic Acid (L-Ascorbic Acid; Vitamin C); E-300; ST24026436; SW198791-2; L-Ascorbic acid, BioUltra, >=99.5% (RT); L-Ascorbic acid, tested according to Ph.Eur.; 3466-EP2269610A2; 3466-EP2269978A2; 3466-EP2269985A2; 3466-EP2269988A2; 3466-EP2269991A2; 3466-EP2270000A1; 3466-EP2270002A1; 3466-EP2270008A1; 3466-EP2270011A1; 3466-EP2270505A1; 3466-EP2272516A2; 3466-EP2272537A2; 3466-EP2272822A1; 3466-EP2272834A1; 3466-EP2272835A1; 3466-EP2272844A1; 3466-EP2275413A1; 3466-EP2277848A1; 3466-EP2277865A1; 3466-EP2281823A2; 3466-EP2284149A1; 3466-EP2284150A2; 3466-EP2284151A2; 3466-EP2284152A2; 3466-EP2284153A2; 3466-EP2284155A2; 3466-EP2284156A2; 3466-EP2284164A2; 3466-EP2284171A1; 3466-EP2284178A2; 3466-EP2284179A2; 3466-EP2287140A2; 3466-EP2287148A2; 3466-EP2287150A2; 3466-EP2287153A1; 3466-EP2287156A1; 3466-EP2289510A1; 3466-EP2289883A1; 3466-EP2289890A1; 3466-EP2289892A1; 3466-EP2292227A2; 3466-EP2292228A1; 3466-EP2292592A1; 3466-EP2292612A2; 3466-EP2292617A1; 3466-EP2295055A2; 3466-EP2295401A2; 3466-EP2295409A1; 3466-EP2295416A2; 3466-EP2295419A2; 3466-EP2295426A1; 3466-EP2295427A1; 3466-EP2295435A1; 3466-EP2298735A1; 3466-EP2298742A1; 3466-EP2298748A2; 3466-EP2298768A1; 3466-EP2298770A1; 3466-EP2298776A1; 3466-EP2301536A1; 3466-EP2301538A1; 3466-EP2301929A1; 3466-EP2301931A1; 3466-EP2301935A1; 3466-EP2301940A1; 3466-EP2305219A1; 3466-EP2305257A1; 3466-EP2305636A1; 3466-EP2305637A2; 3466-EP2305648A1; 3466-EP2305651A1; 3466-EP2305668A1; 3466-EP2305674A1; 3466-EP2305679A1; 3466-EP2305683A1; 3466-EP2308854A1; 3466-EP2308857A1; 3466-EP2308861A1; 3466-EP2308867A2; 3466-EP2308870A2; 3466-EP2311453A1; 3466-EP2311455A1; 3466-EP2311805A1; 3466-EP2311807A1; 3466-EP2311809A1; 3466-EP2311824A1; 3466-EP2311839A1; 3466-EP2311842A2; 3466-EP2314295A1; 3466-EP2314584A1; 3466-EP2314585A1; 3466-EP2314588A1; 3466-EP2314589A1; 3466-EP2314590A1; 3466-EP2314593A1; 3466-EP2316452A1; 3466-EP2316457A1; 3466-EP2316458A1; 3466-EP2316470A2; 3466-EP2316825A1; 3466-EP2316826A1; 3466-EP2316827A1; 3466-EP2316828A1; 3466-EP2316832A1; 3466-EP2316833A1; 3466-EP2316837A1; 3466-EP2374792A1; 3466-EP2377510A1; 3466-EP2380568A1; C 1000; C00072; D00018; L-Ascorbic acid, p.a., ACS reagent, 99.0%; 93398-EP2380568A1; AB00376923_04; AB00376923_05; L-Ascorbic acid, JIS special grade, >=99.0%; L-Ascorbic acid, Vetec(TM) reagent grade, 99%; L-Ascorbic acid, BioXtra, >=99.0%, crystalline; L-Ascorbic acid, puriss. p.a., >=99.0% (RT); L-Threoascorbic acid, Antiscorbutic factor, Vitamin C; L-Threoascorbic acid; Antiscorbutic factor; Vitamin C; 47A605F0-4187-47A8-B0CE-F9E7DA1B0076; L-Ascorbic acid, p.a., ACS reagent, reag. ISO, 99.7%; Ascorbic acid, British Pharmacopoeia (BP) Reference Standard; Ascorbic acid, European Pharmacopoeia (EP) Reference Standard; L-Ascorbic acid, certified reference material, TraceCERT(R); L-Ascorbic acid, powder, cell culture tested, gamma-irradiated; Ascorbic acid, United States Pharmacopeia (USP) Reference Standard; (2R)-2-[(1S)-1,2-dihydroxyethyl]-4,5-dihydroxy-2,3-dihydrofuran-3-one; (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one (non-preferred name); L-Ascorbic acid solution, 1.0 mg/mL in acetonitrile: water, certified reference material; L-Ascorbic acid, anhydrous, free-flowing, Redi-Dri(TM), ACS reagent, >=99%; L-Ascorbic acid, suitable for cell culture, suitable for plant cell culture, >=98%; 178101-88-7; L-Ascorbic Acid (Vitamin C)-13C6 solution, 500 mug/mL in acetonitrile: water, certified reference material, ampule of 1 mL; L-Ascorbic acid, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., 99.7-100.5% (oxidimetric); Valeryl fentanyl hydrochloride solution, 100 mug/mL in methanol (as a free base), certified reference material, ampule of 0.5 mL; l-ascorbic acid; ascorbic acid; vitamin c; l-ascorbate; ascorbat; ascorbicap; l +-ascorbic acid; cevitamic acid; ascolti; L-Ascorbic acid; ascorbic acid; 2,3-didehydro-L-threo-hexono-1,4-lactone; 3-keto-L-gulofuranolactone; ASKORBKAST; ASKORBK AST; askorbik asit; askorbikasit; ASKORBIKASIT; ASKORBIK ASIT; askorbkast; askorbk ast; askor bkast; askor bikasit; Vitamin C; Ascorvit; Vicomin C; Acorbate,
Ascorbutina, , Secorbate; 3-Keto-Lgulofuranolactone; L-Ascorbic Acid
Description
Ascorbic acid, a water-soluble dietary supplement, is consumed by humans more than any other supplement. The name ascorbic means antiscurvy and denotes the ability of ascorbic to combat this disease. Vitamin C is the l-enantiomer of ascorbic acid. Ascorbic acid deficiency in humans results in the body’s inability to synthesize collagen, which is the most abundant protein in vertebrates.
Chemical Properties
White crystals (plates or needles). Soluble in water; slightly soluble in alcohol; insoluble in ether, chloroform, benzene, petroleum ether, oils and fats. Stable to air when dry. One international unit is equivalent to 0.05 milligram of l-ascorbic acid.
Chemical Properties
Ascorbic acid occurs as a white to light-yellow-colored, nonhygroscopic, odorless, crystalline powder or colorless crystals with a sharp, acidic taste. It gradually darkens in color upon exposure to light.
Uses
vitamin C is a well-known anti-oxidant. Its effect on free-radical formation when topically applied to the skin by means of a cream has not been clearly established. The effectiveness of topical applications has been questioned due to vitamin C’s instability (it reacts with water and degrades). Some forms are said to have better stability in water systems. Synthetic analogues such as magnesium ascorbyl phosphate are among those considered more effective, as they tend to be more stable. When evaluating its ability to fight free-radical damage in light of its synergistic effect with vitamin e, vitamin C shines. As vitamin e reacts with a free radical, it, in turn, is damaged by the free radical it is fighting. Vitamin C comes in to repair the free-radical damage in vitamin e, allowing e to continue with its free-radical scavenging duties. Past research has indicated that high concentrations of topically applied vitamin C are photoprotective, and apparently the vitamin preparation used in these studies resisted soap and water, washing, or rubbing for three days. More current research has indicated that vitamin C does add protection against uVB damage when combined with uVB sunscreen chemicals. This would lead one to conclude that in combination with conventional sunscreen agents, vitamin C may allow for longer-lasting, broader sun protection. Again, the synergy between vitamins C and e can yield even better results, as apparently a combination of both provides very good protection from uVB damage. However, vitamin C appears to be significantly better than e at protecting against uVA damage. A further conclusion is that the combination of vitamins C, e, and sunscreen offers greater protection than the sum of the protection offered by any of the three ingredients acting alone. Vitamin C also acts as a collagen biosynthesis regulator. It is known to control intercellular colloidal substances such as collagen, and when formulated into the proper vehicles, can have a skin-lightening effect. Vitamin C is said to be able to help the body fortify against infectious conditions by strengthening the immune system. There is some evidence (although debated) that vitamin C can pass through the layers of the skin and promote healing in tissue damaged by burns or injury. It is found, therefore, in burn ointments and creams used for abrasions. Vitamin C is also popular in anti-aging products. Current studies indicate possible anti-inflammatory properties as well.
Uses
antiscorbutic, antiviral
Uses
analgesic, antipyretic
Uses
Physiological antioxidant. Coenzyme for a number of hydroxylation reactions; required for collagen synthesis. Widely distributed in plants and animals. Inadequate intake results in deficiency syndrome s such as scurvy. Used as antimicrobial and antioxidant in foodstuffs.
Uses
Sodium, potassium, and calcium salts of ascorbic acids are called ascorbates and are used as food preservatives. To make ascorbic acid fat-soluble, it can be esterified. Esters of ascorbic acid and acids, such as palmitic acid to form ascorbyl palmitate and stearic acid to form ascorbic stearate, are used as antioxidants in food, pharmaceuticals, and cosmetics. Ascorbic acid is also essential in the metabolism of some amino acids. It helps protect cells from free radical damage, helps iron absorption, and is essential for many metabolic processes.
Production Methods
Ascorbic acid is produced synthetically using the Reichstein process, which has been the standard method of production since the 1930s. The process starts with fermentation followed by chemical synthesis. The first step involves reduction of D-glucose at high temperature into D-sorbitol. D-sorbitol undergoes bacterial fermentation, converting it into L-sorbose. L-sorbose is then reacted with acetone in the presence of concentrated sulfuric acid to produce diacetone-L-sorbose, which is then oxidized with chlorine and sodium hydroxide to produce di-acetone-ketogulonic acid (DAKS). DAKS is then esterified with an acid catalyst and organics to give a gulonic acid methylester. The latter is heated and reacted with alcohol to produce crude ascorbic acid, which is then recrystallized to increase its purity. Since the development of the Reichstein process more than 70 years ago, it has undergone many modifications. In the 1960s, a method developed in China referred to as the two-stage fermentation process used a second fermentation stage of L-sorbose to produce a different intermediate than DAKS called KGA (2-keto-L-gulonic acid), which was then converted into ascorbic acid. The two stage process relies less on hazardous chemicals and requires less energy to convert glucose to ascorbic acid.
Indications
Vitamin C (ascorbic acid) is essential for the maintenance of the ground substance that binds cells together and for the formation and maintenance of collagen.The exact biochemical role it plays in these functions is not known, but it may be related to its ability to act as an oxidation-reduction system.
Definition
ChEBI: The L-enantiomer of ascorbic acid and conjugate acid of L-ascorbate.
Production Methods
Ascorbic acid is prepared synthetically or extracted from various vegetable sources in which it occurs naturally, such as rose hips, blackcurrants, the juice of citrus fruits, and the ripe fruit of Capsicum annuum L. A common synthetic procedure involves the hydrogenation of D-glucose to D-sorbitol, followed by oxidation using Acetobacter suboxydans to form L-sorbose. A carboxyl group is then added at C1 by air oxidation of the diacetone derivative of Lsorbose and the resulting diacetone-2-keto-L-gulonic acid is converted to L-ascorbic acid by heating with hydrochloric acid.
Brand name: Ascorbin (Marion Merrell Dow).
General Description
White to very pale yellow crystalline powder with a pleasant sharp acidic taste. Almost odorless.
General Description
Scurvy (from the French word scorbutus) has been recognized as a disease afflicting mankind for thousands of years. Citrus fruits such as oranges, lemons, and limes were later identified as equally effective treatments. Only within the last 100 years has a deficiency in vitamin C been definitively identified as the cause of scurvy. In 1932, Waugh and King isolated crystalline vitamin C from lemon juice and showed it to be the antiscorbutic factor present in each of these treatments. The structure and chemical formula of vitamin C was identified in 1933 by Hirst et al.Because humans are one of the few animal species that cannot synthesize vitamin C, it has to be available as a dietary component. Dietary sources of ascorbic acid include fruits (especially citrus fruits), vegetables (especially peppers), and potatoes. Although the sources of some commercial products are rose hips and citrus fruits, most ascorbic acid is prepared synthetically. Vitamin C is now commonly referred to as ascorbic acid because of its acidic character and its effectiveness in the treatment and prevention of scorbutus (scurvy). The acidic character is because of the two enolic hydroxyls; the C3 hydroxyl has a pKa value of 4.1, and the C2 hydroxyl has a pKa of 11.6. All biological activities reside in L-ascorbic acid; therefore, all references to vitamin C, ascorbic acid, ascorbate, and their derivatives refer to this form. The monobasic sodium salt is the usual salt form.
Air & Water Reactions
May be sensitive to prolonged exposure to air and light. Sensitive to moisture. Soluble in water. Aqueous solutions are oxidized by air in a reaction that is accelerated by alkalis, iron and copper. The rate depends on the pH and on oxygen concentration. Also subject to degradation under anaerobic conditions.
Reactivity Profile
L(+)-Ascorbic acid is a lactone. Reacts as a relatively strong reducing agent and decolorizes many dyes. Forms stable metal salts. Incompatible with oxidizers, dyes, alkalis, iron and copper. Also incompatible with ferric salts and salts of heavy metals, particularly copper, zinc and manganese .
Fire Hazard
Flash point data for L(+)-Ascorbic acid are not available; however, L(+)-Ascorbic acid is probably combustible.
Pharmaceutical Applications
Ascorbic acid is used as an antioxidant in aqueous pharmaceutical formulations at a concentration of 0.01-0.1% w/v. Ascorbic acid has been used to adjust the pH of solutions for injection, and as an adjunct for oral liquids. It is also widely used in foods as an antioxidant. Ascorbic acid has also proven useful as a stabilizing agent in mixed micelles containing tetrazepam.
Clinical Use
Vitamin C is indicated for the treatment and prevention of known or suspect deficiency. Although scurvy occurs infrequently, it is seen in the elderly, infants, alcoholics, and drug users.Ascorbate can also be used to enhance absorption of dietary nonheme iron or iron supplements. Ascorbic acid (but not the sodium salt) was historically used to acidify the urine as a result of excretion of unchanged ascorbic acid, although this use has fallen into disfavor. Ascorbate also increases iron chelation by deferoxamine, explaining its use in the treatment of iron toxicity.
Clinical Use
Vitamin C is found in fresh fruit and vegetables. It is very water soluble, is readily destroyed by heat, especially in an alkaline medium, and is rapidly oxidized in air. Fruit and vegetables that have been stored in air, cut or bruised, washed, or cooked may have lost much of their vitamin C content. The deficiency disease associated with a lack of ascorbic acid is called scurvy. Early symptoms include malaise and follicular hyperkeratosis. Capillary fragility results in hemorrhages, particularly of the gums. Abnormal bone and tooth development can occur in growing children.The body’s requirement for vitamin C increases during periods of stress, such as pregnancy and lactation.
Side effects
Megavitamin intake of vitamin C may result in diarrhea due to intestinal irritation. Since ascorbic acid is partially metabolized and excreted as oxalate, renal oxalate stones may form in some patients.
Toxicology
L-Ascorbic acid, or vitamin C, is widely present in plants. The structures of ascorbic acid and dehydroascorbic acid are shown in Figure 10.5. Vitamin C is not only an important nutrient but is also used as an antioxidant in various foods. However, it is not soluble in fat and is unstable under basic conditions. Vitamin C reduces cadmium toxicity and excess doses prolong the retention time of an organic mercury compound in a biological system. Overdoses of vitamin C (106 g) induce perspiration, nervous tension, and lowered pulse rate. WHO recommends that daily intake be less than 0.15 mg/kg. Toxicity due to ascorbic acid has not been reported. Although repeated intravenous injections of 80 mg dehydroascorbic acid was reported to be diabetogenic in rats, oral consumption of 1.5 g/day of ascorbic acid for six weeks had no effect on glucose tolerance or glycosuria in 12 normal adult males and produced no change in blood glucose concentrations in 80 diabetics after five days. The same report noted that a 100-mg intravenous dose of dehydroascorbic acid given daily for prolonged periods produced no signs of diabetes. Ascorbic acid is readily oxidized to dehydroascorbic acid, which is reduced by glutathione in blood.
Safety Profile
Moderately toxic by ingestion and intravenous routes. Human systemic effects by intravenous route: blood, changes in tubules (including acute renal failure, acute tubular necrosis). An experimental teratogen. Other experimental reproductive effects. Mutation data reported. When heated to decomposition it emits acrid smoke and irritating fumes.
Safety
Ascorbic acid is an essential part of the human diet, with 40 mg being the recommended daily dose in the UK and 60 mg in the USA. However, these figures are controversial, with some advocating doses of 150 or 250mg daily. Megadoses of 10 g daily have also been suggested to prevent illness although such large doses are now generally considered to be potentially harmful.
The body can absorb about 500 mg of ascorbic acid daily with any excess immediately excreted by the kidneys. Large doses may cause diarrhea or other gastrointestinal disturbances. Damage to the teeth has also been reported. However, no adverse effects have been reported at the levels employed as an antioxidant in foods, beverages, and pharmaceuticals. The WHO has set an acceptable daily intake of ascorbic acid, potassium ascorbate, and sodium ascorbate, as antioxidants in food, at up to 15 mg/kg bodyweight in addition to that naturally present in food.
LD50 (mouse, IV): 0.52 g/kg
LD50 (mouse, oral): 3.37 g/kg
LD50 (rat, oral): 11.9 g/kg
Storage
In powder form, ascorbic acid is relatively stable in air. In the absence of oxygen and other oxidizing agents it is also heat stable. Ascorbic acid is unstable in solution, especially alkaline solution, readily undergoing oxidation on exposure to the air.The oxidation process is accelerated by light and heat and is catalyzed by traces of copper and iron. Ascorbic acid solutions exhibit maximum stability at about pH 5.4. Solutions may be sterilized by filtration. The bulk material should be stored in a well-closed nonmetallic container, protected from light, in a cool, dry place.
Purification Methods
Crystallise it from MeOH/Et2O/pet ether [Herbert et al. J Chem Soc 1270 1933]. [Beilstein 18/5 V 26.]
Incompatibilities
Incompatible with alkalis, heavy metal ions, especially copper and iron, oxidizing materials, methenamine, phenylephrine hydrochloride, pyrilamine maleate, salicylamide, sodium nitrite, sodium salicylate, theobromine salicylate, and picotamide. Additionally, ascorbic acid has been found to interfere with certain colorimetric assays by reducing the intensity of the color produced.
Regulatory Status
GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (inhalations, injections, oral capsules, suspensions, tablets, topical preparations, and suppositories). Included in medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.C-Long
Appearance: Powder
Color: White slightly yellow
Solution in Water : Clear and colourless
Ph : 2.2 – 2.5
Chemical Name or Material: Ascorbic Acid
Packaging: Wide Mouth Amber Glass Bottle
Quantity: 500g
Molecular Formula: C6H8O6
InChI Key: CIWBSHSKHKDKBQ-JLAZNSOCSA-N
IUPAC Name: (2R)-2-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2H-furan-5-one
PubChem CID: 54670067
Formula Weight: 176.12
Grade: Multi-Compendial/USP
Mesh Size: 200 to 325 Mesh
Specific Gravity: 1L = 1.65kg
CAS: 50-81-7
SMILES: C(C(C1C(=C(C(=O)O1)O)O)O)O
Molecular Weight (g/mol): 176.124
Physical Form: Fine Powder
Typical usage rate: 1-4%
Appearance: Ultrafine white crystalline powder
Mesh Size: 100% through sieve No. 100, min. 95% through sieve No. 200 (75 microns)
pH (5% solution): 2.2 – 2.5
Solubility: Freely soluble in water (approx. 30g/100ml), sparingly soluble in absolute ethanol (2g/100ml), insoluble in fats and lipids.
Ascorbic acid is a naturally occurring organic compound with antioxidant properties. It is a white solid, but impure samples can appear yellowish. It dissolves well in water to give mildly acidic solutions. Ascorbic acid is one form of vitamin C. It was originally called L-hexuronic acid, but, when it was found to have vitamin C activity in animals, the suggestion was made to rename L-hexuronic acid. The new name for L-hexuronic acid is derived from a- and scorbutus, the disease caused by a deficiency of vitamin C. Because it is derived from glucose, many animals are able to produce it, but humans require it as part of their nutrition. Other vertebrates lacking the ability to produce ascorbic acid include other primates, guinea pigs, teleost fishes, bats, and some birds, all of which requiring it as a dietary micronutrient. There exists a D-ascorbic acid, which does not occur in nature. It may be synthesized artificially. It has identical antioxidant properties to L-ascorbic acid yet has far less vitamin C activity. This fact is taken as evidence that the antioxidant properties of ascorbic acid are only a small part of its effective vitamin activity. Ascorbic Acid Fine Granular, also known as Vitamin C, is an essential health ingredient that the body is incapable of producing by itself. This product is recommended for general food fortification, as a dough conditioner, and as an antioxidant for curing meats. It is suitable in both solid and liquid vitamin/mineral formulations. Vitamin C, 100% L-Ascorbic Acid, FCC, Ultrafine powder is a water soluble antioxidant. Vitamin C, a potent, naturally occurring antioxidant is an important constituent of skin. It plays a pivotal role in the prevention of dry skin and wrinkles, collagen synthesis and skin regeneration. Ascorbate is found in all layers of the skin, but is more concentrated in the epidermis than the dermis. However, it is readily depleted by about two thirds in cutaneous tissue stores with exposure to UV light. Biochemically, the body relies on ascorbate in the collagen biosynthetic pathway. It functions as a cofactor for two enzymes, lysyl and prolyl hydroxylases. These are dependent on iron and Vitamin C prevents iron oxidation and thus inactivation of these hydroxylases, thereby maintaining their activity. Vitamin C has been shown to be effective in increasing collagen deposits and also enhancing collagen lattice contractions, implying that exogenous Vitamin C application contributes to strengthening the collagen framework and maintaining a healthy dermis. Topical application of Vitamin C has been shown to reduce the appearance of fine lines and wrinkles. Caused by mechanisms supporting collagen production, this leads to improving the appearance of the skin. It has further been proven to reduce the severity of sunburns and age spots. Cutaneous levels of Vitamin C cannot be achieved well by ingestion, hence topical application is essential for preventing oxidative damage resulting from pollution, smoke and sunlight. Its use has been shown to increase generation of stratum corneum barrier lipids and stabilize lipid profiles, in particular glucosphingolipids and ceramides. The difficulty for the cosmetic formulator is that L-Ascorbic Acid is very unstable in aqueous solutions, as it starts to oxidize immediately, gradually producing color changes (orange/brown shift) and a reduction in activity as it converts to dehydroascorbic acid. For cosmetic use, it is best stabilized in an anhydrous lipid or silicone base, although some have reported increased stability with the use of Ferulic Acid as part of aqueous formulations. This product is an ultrafine powder, ready to use in anhydrous formulations without further grinding. Our L-Ascorbic Acid meets FCC specifications, but it is considered a cosmetic grade material once we repackage it. This is a cosmetic raw material and is meant for external use only in cosmetic formulations. As with all of our materials, it should not be taken internally. Topical Vitamin C offers a wide array of benefits to the skin. However, many forms of Vitamin C and many more formulations of Vitamin C are available commercially with a potential to confuse the audience. We have developed a guide that offers guidance on the formulations of Vitamin C offered under The Ordinary range. It also offers education on Vitamin C itself and on the differences between formulations of Vitamin C at large. Please click here for this guide.
Shelf Life: The manufacturer’s stated “best use” date is two years from date of manufacture, if the container is unopened and stored away from heat, light and air. We repackage this product in foil bags with a zip seal and a dessicant and oxygen absorbing pack. Please do not throw away these packs as they help protect your product! Close the bag quickly, expelling as much air as possible from the bag. Over time, constant opening and closing of the bag will eventually deplete the ability of the dessicant pack to adsorb moisture and the oxygen absorbent to absorb oxygen and allow the l-ascorbic acid to adsorb the moisture in the air and, in the presence of oxygen, it will begin to oxidize. This will be noticeable as it takes on a yellow color in solution. Please consider purchasing sizes suitable for use in a period of 3-4 months. If you are using this daily, it is better to purchase 1oz packets of l-ascorbic acid rather than a 4 – 8 oz bag that will be opened frequently and take a long time to use up.
INCI: Ascorbic Acid
California Prop 65 Statement: The following statement is made in order to comply with the California Safe Drinking Water and Toxic Enforcement Act of 1986. This product is not known to the State of California to cause cancer, birth defects or other reproductive harm. L-Ascorbic Acid (Vitamin C, L-AA) products are so prolific in the skincare industry, it may feel like brands are beating a dead horse. The reality is – it works! In fact, it’s quite the skincare multi-tasker. L-AA has decades of clinical testing to prove that it is an effective free radical quencher and skin brightener. Let’s dive in to take a closer look at this chemist favorite molecule.
How does L-Ascorbic Acid work?
Free radicals leads to all sorts of unwanted aging symptoms. Enter L-ascorbic acid (L-AA), your best in class radical-quenching antioxidant here to save the day. Antioxidants like L-AA sacrifices itself to bond to the free radicals, saving your skin cells. This is why, in a nutshell, L-AA is an essential part of your long-term age prevention care. Age prevention through radical quenching isn’t L-AA’s only benefit. It has been shown to have visible skin tone, texture improvements within 4 to 12 weeks of consistent use. L-AA has also demonstrated to treat melasma and hyperpigmentation effectively either alone or used in conjunction with other brightening actives. Lastly, L-AA boosts collagen synthesis. Since collagens are the pillars of your skin structural integrity, this explains why L-AA also helps with minimizing fine lines and wrinkles.
To sum up: L-AA is an age-preventing antioxidant that brightens skin and boosts collagen production. Everyone could use some L-AA in their life.
How do I choose a good L-AA product?
Like all powerhouse actives, there’s always a catch. L-AA is infamously unstable in water, and can be a pain in the butt to formulate. Trust us, we know. CE Ferulic products are classic examples of using antioxidants to helps stabilize vitamin C in water solutions.To get the most out of your L-AA product, you must choose one that’s formulated correctly so that it remains stable long enough for you to get all the benefits out of it. For L-AA to remain stable and effectively penetrate your skin, pH of the formula needs to be under 3.5. There should also be other antioxidants like vitamin E and ferulic acid to prevent vitamin C degradation. Because of the low pH, some people may find L-AA products irritating. Start with a lower concentration if you’re new to this little guy! L-AA is effective starting at 5%, and you can ramp it up all the way to ~20%! Here are some products featuring the classic C+E+Ferulic combination. Another way to prevent the degradation problem is to use water-free (anhydrous) formulas. These usually consist of a finely ground vitamin C powder that is suspended in silicone. These formulas don’t penetrate as well as their water-based counterparts, so the concentration is usually a bit higher. We are personally not huge fans of these formulas (pet peeve about how these formulas feel!), but they can work well for those irritated by the low pH water-based formulas. Powdered Vitamin C is the most stable type of vitamin C available on the market. But the downside is that you never know if you’re adding quite the right amount to your regimen. Not to mention the messiness. Powdered vitamin C products are by far the most stable options on the market. But the downside is that you never know if you’re adding quite the right amount to your regimen. Not to mention the messiness. Sold!
How do I include vitamin C in my routine?
You can use L-AA products both day and night. It’s best to use it daily in the morning on cleansed skin before moisturizer and sunscreen to get the most out of its radical scavenging prowess.
Definition: a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy
Similar words: antioxidant
Definition: substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides
Similar words: water-soluble vitamin
Definition: any vitamin that is soluble in water
What it does: Antioxidant protection, skin brightening, boosts collagen production.
Effective Concentration: at minimum 5%, but usually 10% and up.
pH: Effective and stable at ~3.5 and under.
Other concerns? HIGHLY. UNSTABLE. Choose products carefully.
PS. There are a lot of products out there that feature vitamin C derivatives like ascorbyl palmitate, tetrahexyldecyl ascorbate, etc. None of them hold a candle to L-ascorbic acid in terms of the number of clinical tests and data that support their skincare benefits. However, they may still be good options for those who just can’t tolerate L-AA at all. Just remember, the dose makes the poison and don’t settle for a product that won’t tell you how much you’re getting.
Fine 325 Mesh Topical Powder
Vitamin C is an effective antioxidant that brightens the skin tone and reduces the appearance of signs of aging. This formula offers a very fine L-Ascorbic Acid powder that visibly targets the appearance of uneven skin tone, dullness, and signs of aging and is formulated to be mixed with other treatments (except those containing Niacinamide or EUK 134). The format of this formula is a very fine, anhydrous, L-Ascorbic Acid powder and, as such, provides the most direct exposure of extremely high concentrations of Vitamin C topically. With such format, a very strong tingling but non-irritating sensation is expected during the first 1-2 weeks of use until the skin’s tolerance to such high exposure is elevated. If topical Vitamin C is used as part of skincare, it should be applied at alternate times with EUK 134 or Niacinamide (ideally Vitamin C in the PM and EUK 134/Niacinamide in the AM). Otherwise, EUK 134/Niacinamide can affect the integrity of pure-form Vitamin C (L-Ascorbic Acid). The Ordinary’s portfolio of Vitamin C includes the following formulations:
Vitamin C Suspension 30% in Silicone
Vitamin C Suspension 23% + HA Spheres 2%
Ascorbyl Glucoside Solution 12%
Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F
Magnesium Ascorbyl Phosphate 10%
Ascorbic Acid 8% + Alpha Arbutin 2%
Ethylated Ascorbic Acid 15% Solution
100% L-Ascorbic Acid Powder
Directions
Mix a small amount with other treatments in the palm of your hand and apply to face in the AM or the PM. Avoid contact with the eyes. A tingling sensation can be expected after application. Do not mix with formulations containing Niacinamide or EUK 134. If irritation occurs, cease use and consult a physician. Use only as directed on unbroken skin. Patch testing prior to use is advised. Refer to our in-depth guide to patch testing. Keep out of reach of children.
Ingredients
Ascorbic Acid
Our formulations are updated from time to time as part of our commitment to innovation. As such, the ingredient list shown here may vary from the box of the product depending on time and region of purchase.
Benefits: USP/FCC grade
Potent antioxidant (shown to be able to protect skin from oxidative damages): Can improve appearance of aged and fragile skin
Widely used as add-on ingredient in skin-lightening products to correct hyperpigmentation and age spots
Antioxidant effect can be increased by combining L-ascorbic acid with L-ascorbyl palmitate and/or vitamin E
Use: Add to water phase of formula, usual final concentration 0.5-10 %. Tip: sprinkle vitamin C powder slowly to the water under constant stirring to assure that everything dissolves completely. Should be formulated at pH 4-5 for best results. For external use only.
Applications: Lotions, creams, sun care & after sun products, shampoos, makeup products (e.g. lipsticks).
Country of Origin: UK & China
Raw material source: Glucose (derived from corn or wheat starch)
Manufacture: L-ascorbic acid is produced synthetically in a multi-step process where D-glucose is hydrogenized to D-sorbitol and then oxidized to L-sorbose. Sorbose is then processed to 2-keto-L-gluconic acid and further to l-ascorbic acid through a fermentation process.
Animal Testing: Not animal tested
GMO: GMO free (does not contain plant-derived components)
Vegan: Does not contain animal-derived components
ASKORBK AST
Görünümü : Kristal,Toz Beyaz Renkte
Salkl bir geliim, di, kemik ve deri için vazgeçilmez bir bileen olan C vitamini olarak da adlandrlan L-askorbik asit (3-keto-L-gulofuranolaktan); demirin absorblanmas, kolajen sentezi, kan damarlarnn yapsal gücünün sürdürülmesi, baz aminoasitlerin metabolizmasnda ve adrenal bezlerin hormon sentezi ve salglamas gibi metabolik fonksiyonlarda görev alan karbonhidrat benzeri bir kimyasal maddedir. Askorbik asit; beyaz veya hafif sar renkte, kokusuz kristalimsi yapda bir madde olup suda tamamen çözünürken etanolde biraz çözünmekte dietil eter çözeltisi içinde ise hiç çözünmemektedir. Askorbik asitin geleneksel yolla elde edilmesi, sorbitolün yedi basamakl kimyasal bir süreç olan Reichstein prosesi ile biyodönüüme uratlmasyla olurken, yeni gelitirilmi fermantasyon teknolojisi ile bu süreçte önemli bir bileen olan ketogulanik asit üretim maliyetleri düürülerek önemli bir ilerleme kaydedilmitir. Askorbik asit, genellikle pH kontrolü amacyla bir asit düzenleyici olarak kullanlmasna ramen, gda ürünlerinde asidik bir tat vermektedir. Bira endüstrisinde antioksidan olarak kullanlan askorbik asit; bulankl engelleyerek birann raf ömrünü iyiletirmekte, et endüstrisinde rengin sürdürülmesi ile ilgili olarak koruyucu görev yapmakta iken, frnclk endüstrisinde gelitirici ajan olarak, meyve pulp ve sularnda ise renk solmasnn önlenmesinde kullanlmaktadr. Bunun dnda tereya, donmu yumurta ürünleri, toz ve konsantre süt, donmu patates vb ürünlerde. bunlara benzer görevler yapabilmektedir. Sodyum askorbat ve potasyum askorbat olmak üzere iki adet tuzu olan askorbik asit, özellikle konserve veya ielenmi ürünler gibi tepe boluu olan ürünlerde oksijen tutucu olarak kullanlmaktadr. Askorbik asitin sodyum ve kalsiyum tuzlar; suda çözündüünden yalar oksidasyondan koruyamamaktadr. Bu amaçla ya asiti esterleri olan askorbil palmital ve askorbil steorat kullanlmaktadr. Bu esterler, beyaz veya sarms beyaz kristal toz halde, turunçgil kokusuna benzer hafif kokulu olup, gdalarda oksijen tutucu etkisi olan maddelerdir.(lgili gda katk maddelerinin srasyla numaralar u ekildedir: E300 askorbik asit, E301 sodyum askorbat, E302 kalsiyum askorbat, E303 potasyum askorbat, E304 askorbik asitin ya asidi esterleri ? askorbil palmitat ve askorbil stearat ). Askorbik asit, oksijeni absorblayarak tersinir bir tepkime ile dehidroaskorbik asite dönümektedir. Bu önemli fonksiyon, meyve ve sebzelerde oksidatif esmerlemeyi, et ve deniz ürünlerinde ransiditeyi, sütte arzu edilmeyen koku geliimini önlemektedir. C vitamini katk olarak; vitamin preparatlar, içecek ürünleri ve hayvan yemlerinde kullanlmaktadr. Gdalarn C vitamini ile zenginletirilmesi srasnda, askorbik asit hali hazrda antioksidan olarak görev yapmakta ve vitamin deeri zedelenmektedir. Bunun önüne geçilebilmesi için C vitamini ile zenginletirilmek istenen ürünlerde, stabilitenin salanmas serbest oksijenin elemine edilmesiyle gerçekletirilmektedir. Meyve sebze ilemede oksidasyona maruz kalan bir askorbik asit çözeltisinde, askorbik asit oksidasyon ve ayrma ürünleri olan 3-deoxy-L-pentose ve furfuralin?e parçalanr. Böylece oksijen ile kendisi reaksiyon vererek proseste ki dier bileenlerin oksijenle okside olmasn engellemi olur. Oksijen varl, scaklk yükselmesi, güne ve ultraviyole klara maruz kalma, bakr ve demir gibi ar metallerin varl, güçlü asit ve alkali koullar gibi durumlarda bu oksidasyonun derecesi artmaktadr. Bu nedenle askorbik asit; karanlk, soukta ve metal olmayan kaplarda depolanmaldr.
C vitamini, askorbik asit olarak da bilinir, suda eritilebilen ve birçok görevi olan vitamin. Çou hayvanlar ve bitkiler, kendi C vitaminlerini glukozdan üretebilirler. nsanlar, baz meyve yarasalar, hint domuzu ve insan benzeri primatlar C vitamini üretemediklerinden bunu besinlerden almak zorundadrlar. Askorbik asit bir monosakkarit türevi olup yapca glikoza ve dier alt karbonlu monosakkaritlere benzer. Renksiz, beyaz, dikdörtgen kristallerdir. Çok hafif özel bir kokusu vardr. Eki tatta ve asit reaksiyondadr. Optikçe aktiftir. Polarize saa çevirir. Asetonda çok zor çözünür. Eter, petrol eteri, benzen, kloroform ve yalarda çözünmez.C vitamini kimyasal olarak askorbik asidin sola döndüren enantiyomeridir. Ticari C vitamini genelde askorbik asit kristallerinden veya askorbik asidin kalsiyum veya sodyum tuzlarndan olumaktadr.C vitamini (askorbik asid) omurilik, akcier ve göz gibi pek çok hayvansal dokunun sulu bölümlerinde oldukça yüksek younlukta (milimolar ve üstü) bulunur. C vitamininin kesin ölçümü hem onun biyokimyasal hem de farmakokinetik özellikleri için zorunludur. Biyolojik sistemlerde askorbik asidin rolü, C vitamininin fonksiyon ve gerekleri iki faktörle birlikte ele alnmaldr: Birincisi, C vitamininin hem antioksidan hem de bir enzim kofaktörü olarak hareket etme yetenei dahil biyokimyasal özellikleridir. kincisi, barsakta emilmeyi, serum konsantrasyonunu, hücresel dalm, kullanm ve dar atlmn içeren farmakokinetiidir. Askorbik asit bütün canl dokularda bulunur. Doada çok yaygn ekilde bulunan bu vitaminin en zengin kaynaklarn taze meyve ve sebzeler oluturur. Meyveler arasnda en çok askorbik asit içerenler; limon, portakal, greyfurt, kivi, ananas, çilek ve frenk üzümüdür. Elma, armut ve erik ise bunlara göre daha az miktarda askorbik asit içerir. Bu meyvelerden özellikle sitrus meyveleri (limon, portakal, greyfurt), kivi ve domatesin d ksmlar (kabuk) askorbik asit bakmndan zengindir. Sebzeler, özellikle kuburnu, karnabahar, lahana, spanak, kuru soan, biber, turp, tere, maydanoz ve yer elmas askorbik asit bakmndan en zengin kaynaklardandr.
Tarihçe
Askorbik asit üzerinde ilk bilimsel aratrmalar 1907’de Holst ve Frolich tarafndan yaplan deneylerle balar. Aratrmalarn sürdüren Holst ve Frolich birçok besin maddesinin ve bu arada özellikle yeil sebze ve meyvelerin skorbüt hastaln önleyici etkileri olduunu bulmulardr. C. Funk 1912’de skorbüt hastalnn besinlerde bulunan bir faktörün eksiklii sonucu olutuu düüncesini ortaya koymu ve bu maddeye antiskorbutik vitamin adn vermitir. Daha sonra Drummond 1920’de antiskorbutik vitamin için Vitamin C adn kullanmtr. Zilva ve çalma arkadalar (1918-1929) limondan antiskorbutik faktörü younlatrma üzerinde çalmlar ve hemen hemen saf askorbik asit baz fiziksel ve kimyasal özellikleri belirlenerek izole edilmitir. Zilva bu çalmalar esnasnda 2,6-diklorofenolindofenolün (2,6-DCPIP) vitamin çözeltisi tarafndan indirgendiini de bulmutur. Zilva deneylerini sürdürürken Szent-Gyorki 1928 ylnda portakal, lahana ve hayvanlarn adrenal bezlerinden askorbik asidi ayrm fakat 1932 ylna dek bu maddenin antiskorbüt vitamini olduunu anlayamamtr. Buluunu yaymlamadan King bu aratrmadan habersiz heksuronik asit ile ayn olduunu kabul ettikleri kristal maddenin limon suyundan izolasyonunu bildirmitir. Bundan sonra birçok bamsz aratrclar özellikle Tillmans, Vedder, Nelson, Harris ve Von Vargha vitaminin kimliini saptamlar ve glikozdan sentezini gerçekletirmilerdir. Askorbik asit ismi Szent-Gyorki’e izafeten verilmitir. Askorbik asit ve vitamin C, L-ksiloaskorbik asidin günümüzde yaygn olarak kullanlan iki ismidir. Bununla beraber tarihsel geliimi srasnda cevitamik asit, antiskorbutik vitamin, heksuronik asit, skorbutamin ve redoxon olarak adlandrlmtr. Dier kimyasal isimleri; L-askorbik asit, 3-Oxo-L-glufuranolaktonel (enol form), L-3-ketotreoheksuronikasitlaktondur.
Genel özellikleri
Askorbik asit bir monosakkarit türevi olup yapca glikoza ve dier alt karbonlu monosakkaritlere benzer. Renksiz, beyaz, dikdörtgen kristallerdir. Çok hafif özel bir kokusu vardr. Eki tatta ve asit reaksiyondadr. Optikçe aktiftir. Polarize saa çevirir. Asetonda çok zor çözünür. Eter, petrol eteri, benzen, kloroform ve yalarda çözünmez. C vitamini kimyasal olarak askorbik asidin sola döndüren enantiyomeridir. Ticari C vitamini genelde askorbik asit kristallerinden veya askorbik asidin kalsiyum veya sodyum tuzlarndan olumaktadr. C vitamini (askorbik asid) omurilik, akcier ve göz gibi pek çok hayvansal dokunun sulu bölümlerinde oldukça yüksek younlukta (milimolar ve üstü) bulunur. Baz meyveler yüzde 1’den fazla (~6 mM) içerebilir. nsan kan plazmasnda normal olarak 0,1 mM düzeyinde bulunur. Çou organizma C vitaminini sentezleyebilmesine ramen, insanlar dahil birkaç onu diyetle almak zorundadrlar. Enediol yapsndan ötürü, hayli düük bir ilk pKa sergiler (4,2 civarnda) ve buna bal olarak da çou dokularda monoanyon olarak varolur. 3- pozisyonundaki hidrojen de, ki en asidik olandr, tek elektronlu oksidasyon reaksiyonlarnda çkarlan hidrojen atomudur. C vitamininin kesin ölçümü hem onun biyokimyasal hem de farmakokinetik özellikleri için zorunludur. Biyolojik sistemlerde askorbik asidin rolü, C vitamininin in vivo fonksiyon ve gerekleri iki faktörle birlikte ele alnmaldr: Birincisi, C vitamininin hem antioksidan hem de bir enzim kofaktörü olarak hareket etme yetenei dahil biyokimyasal özellikleridir. kincisi, barsakta emilmeyi, serum konsantrasyonunu, hücresel dalm, kullanm ve dar atlmn içeren farmakokinetiidir.
Kaynaklar ve kullanm alanlar
Askorbik asit bütün canl dokularda bulunur. Doada çok yaygn ekilde bulunan bu vitaminin en zengin kaynaklarn taze meyve ve sebzeler ve çi et oluturur. Meyveler arasnda en çok askorbik asit içerenler; limon, portakal, greyfurt, kivi, ananas, çilek ve frenk üzümüdür. Elma, armut ve erik ise bunlara göre daha az miktarda askorbik asit içerir. Bu meyvelerden özellikle sitrus meyveleri (limon, portakal, greyfurt), kivi ve domatesin d ksmlar (kabuk) askorbik asit bakmndan zengindir. Sebzeler, özellikle kuburnu, karnabahar, lahana, spanak, kuru soan, biber, turp, tere, maydanoz ve yer elmas askorbik asit bakmndan en zengin kaynaklardandr. Aadaki tabloda çeitli sebze ve meyvelerin askorbik asit deerleri görülmektedir.
-Borik asit, karncalar, zararl böcekleri, hamamböcei ve çeitli böcekler gibi çok çeitli zararllar kontrol etmek için kullanlmtr.
-Ayrca narenciye için mantar ilac, yol hakk boyunca herbisit, ate önleyici ve odun koruyucusu olarak da kullanlmaktadr.
-Bir herbisit olarak kullanldnda kuruma olur ve bitkilerde fotosentezi bozar.
-Borik asit ayrca ana kullanm alan tekstil fiberglasnn imalatnda olmak üzere sanayide kullanlmaktadr.
-Tekneler, bilgisayar devre kartlar ve borular gibi çeitli ürünlerdeki plastikleri takviye etmek için kullanlr.
-Çözelti formunda veya kuru toz halinde kullanlabilir.
-Borik asit, andrlm ciltlere veya göz ykama svsna uygulanmas gibi çeitli tbbi amaçlar için bile kullanlr. Kesiklerden ve minör yanklardan kurtulmak için antiseptik olarak kullanlr.