(as′id)

[L. acidus, sour]

1. Any substance that liberates hydrogen ions (protons) in solution; a hydrogen ion donor. An acid reacts with a metal to form a salt, neutralizes bases, and turns litmus paper red.
2. A substance that can accept a pair of electrons; a Lewis acid.
SEE: alkali; SEE: base; SEE: indicator; SEE: Lewis acid; SEE: pH
3. A sour substance.
4. Slang term for lysergic acid diethylamide (LSD).

acetic acid

C₂H₄O₂, the acid that gives the sour taste to vinegar. It is also used as a reagent. Glacial (highly purified) acetic acid contains at least 99.5% acetic acid by weight.
CAS# 64-19-7

acetoacetic acid

C₄H₆O₃, a ketone body formed when fats are incompletely oxidized. It was formerly called acetylacetic acid.
SYN: SEE: diacetic acid
CAS# 541-50-4

acetylacetic acid

SEE: acetoacetic acid

acetylsalicylic acid

ABBR: ASA SEE: Aspirin (1).

acrylic acid

C₃H₄O₂, a colorless corrosive acid used in making acrylic polymers and resins.
CAS# 79-10-7

adenylic acid

SEE: Adenosine monophosphate.

alpha-hydroxy acid

ABBR: AHA Any of a class of water-soluble acids derived from fruit or milk, having a hydroxyl moiety in the first position in the molecule. AHAs are used in chemical peels and other skin care products to remove the outer layer of the epidermis. This chemical exfoliation is promoted for its cosmetic effects on wrinkled or sun-damaged skin.

alpha-linolenic acid

C₁₈H₃₀O₂, an omega-3 fatty acid derived from plants, esp. seeds (canola oil, flaxseed, walnuts, and pumpkins) and from some fish (salmon and mackerel).
CAS# 463-40-1

alpha-lipoic acid

C₈H₁₄O₂S₂, a natural coenzyme and antioxidant, used for short-term treatment of peripheral neuropathies.
CAS# 1200-22-2

amino acid

SEE: amino acid

aminoacetic acid

SEE: Glycine.

aminobenzoic acid

SEE: Para-aminobenzoic acid.

aminocaproic acid

C₆H₁₃NO₂, a hemostatic drug. It is a specific antidote for an overdose of a fibrinolytic agent.
CAS# 60-32-2

aminoglutaric acid

SEE: Glutamic acid.

aminosalicylic acid

SEE: Para-aminosalicylic acid.

aminosuccinic acid

SEE: Aspartic acid.

arachidonic acid

C₂₀H₃₂O₂, an omega-6 fatty acid formed by the action of enzymes on phospholipids in cell membranes. The acid is found in many foods. It is metabolized primarily by the cyclo-oxygenase or 5-lipoxygenase pathways to produce prostaglandins and leukotrienes, which are important mediators of inflammation. Corticosteroids inhibit formation of arachidonic acid from phospholipids when cell membranes are damaged. Nonsteroidal anti-inflammatory agents such as salicylates, indomethacin, and ibuprofen inhibit the synthesis of prostaglandins and leukotrienes.
CAS# 506-32-1

argininosuccinic acid

C₁₀H₁₈N₄O₆, a compound intermediate in the synthesis of arginine, formed from citrulline and aspartic acid.
CAS# 2387-71-5

aristolochic acid

C₁₇H₁₁NO₇, an acid derived from Aristolochia, a genus of flowering plants, and used as an herbal remedy. It is promoted as an aphrodisiac, a weight loss agent, and an anticonvulsant.
CAS # 313-67-7

The acid is a known carcinogen, and its use has been associated with and may cause end-stage renal disease and cancers of the urinary tract that may occur many years after usage has stopped.

ascorbic acid

SEE: Vitamin C.

aspartic acid

C₄H₇NO₄, a nonessential amino acid. It is a building block of proteins, participates in the citric acid and urea cycles, and is a neurotransmitter.
SYN: SEE: aminosuccinic acid
CAS# 617-45-8

barbituric acid

C₄H₄N₂O₃, a crystalline acid from which phenobarbital and other barbiturates are derived.
CAS# 67-52-7

benzoic acid

C₇H₆O₂, a white crystalline acid having a slight odor. It is used in keratolytic ointments and in food preservation. Saccharin is a derivative of this acid.
CAS# 65-85-0

beta-hydroxybutyric acid

C₄H₈O₃, any of the acids present in the urine, esp. in diabetic ketoacidosis, when the conversion of fatty acids to ketones increases.

bile acid

Any of the complex acids that occur as salts in bile, e.g., cholic, glycocholic, and taurocholic acids. They give bile its foamy character, are important in the digestion of fats in the intestine, and are reabsorbed from the intestine to be used again by the liver.
SEE: enterohepatic circulation

binary acid

An acid containing hydrogen and one other element.

boric acid

H₃BO₃, a white crystalline acid that in water forms a very weak acid solution poisonous to plants and animals. It is soluble in water, alcohol, and glycerin.
SEE: boric acid poisoning
CAS# 10043-35-3

Boric acid is toxic and should be used only rarely. It is particularly dangerous because it can be accidentally swallowed by children or used in food because of its resemblance to sugar.

butyric acid

C₄H₈O₂, a viscous fatty acid with a rancid odor, derived from butter but rare in most fats. It is used in disinfectants, emulsifying agents, and pharmaceuticals.
CAS# 107-92-6

carbolic acid

SEE: Phenol (1).

carbonic acid

H₂CO₃, an acid formed when carbon dioxide is dissolved in water.
CAS# 463-79-6

carboxylic acid

Any acid containing the carboxyl group −COOH. The simplest examples are formic and acetic acids.

cell-free fetal nucleic acid

SEE: Free fetal nucleic acid.

cholic acid

C₂₄H₄₀O₅, a bile acid formed in the liver by hydrolysis of other bile acids. It is formed from the breakdown of cholesterol and helps digest consumed fats.
CAS# 81-25-4

cinnamic acid

C₉H₈O₂, an insoluble white powder derived from cinnamon. It is used as a flavoring agent in cooking and in the preparation of perfumes and medicines.
CAS# 140-10-3

citric acid

C₆H₈O₇, an acid found naturally in citrus fruits or prepared synthetically. It acts as a sequestrant, helping to preserve food quality.
CAS# 77-92-9

conjugated linoleic acid

ABBR: CLA Any of the isomers of linoleic acid effective against cancer, obesity, diabetes, and atheromata in laboratory rodents. CLAs have not been shown to have similar beneficial effects in humans.

cysteic acid

C₃H₇NO₅S, an acid produced by the oxidation of cysteine. Further oxidation produces taurine.
CAS# 498-40-8

deoxycholic acid

C₂₄H₄₀O₄, a crystalline acid found in bile.
CAS# 83-44-3

deoxyribonucleic acid

desoxyribonucleic acid
SEE: DNA

diacetic acid

SEE: Acetoacetic acid.

2,4-dichlorophenoxyacetic acid

SEE: 2,4-D.

p-dichlorosulfamoyl benzoicacid

SEE: Halazone.

4,8-dihydroxyquinaldic acid

SEE: Xanthurenic acid.

docosahexaenoic acid

docosahexanoic ABBR: DHA C₂₂H₃₂O₂, an omega-3 fatty acid found in the oils of cold-water fish and in algae. DHA plays a role in the development of nerve cell membranes and is required for the normal growth and development of the infant brain. Lack of DHA has been linked to growing numbers of people suffering from depression.
CAS# 6217-54-5

domoic acid

C₁₅H₂₀NO₆, a toxin that resembles glutamate, the main excitatory amino acid of the brain. When ingested, it may cause continuous seizures.
CAS# 14277-97-5

eicosapentaenoic acid

ABBR: EPA C₂₀H₃₀O₂, an omega-3 fatty acid found in fish oils, containing 20 carbons and five double bonds.
CAS# 10417-94-4

endogenous uric acid

Uric acid derived from purines undergoing metabolism from the nucleic acid of body tissues.

essential fatty acid

ABBR: EFA A fatty acid (alpha-linoleic and linoleic) that is essential for health and must be present in the diet because it cannot be synthesized in the body.
SEE: digestion

ethylenediaminetetraacetic acid

ABBR: EDTA C₁₀H₁₆N₂O₈, a chelating agent that, in its calcium or sodium salts, is used to remove metallic ions such as lead and cadmium from the body, as a food preservative, and as an anticoagulant for phlebotomized blood samples.
SEE: chelation
CAS# 60-00-4

exogenous uric acid

Uric acid derived from purines from food made up of free purines and nucleic acids.
SEE: urate; SEE: uraturia

fatty acid

Any of numerous monobasic acids with the general formula C_nH_2n+1−COOH (an alkyl radical attached to a carboxyl group).
Fatty acids are insoluble in water, but bile salts secreted into the small intestine allow them to be absorbed after they are eaten. Fatty acids include acetic, butyric, capric, caproic, caprylic, formic, lauric, myristic, palmitic, and stearic acids. Unsaturated fatty acids have one or more double or triple bonds in the carbon chain. They include those of the oleic series (oleic, tiglic, hypogeic, and palmitoleic) and the linoleic or linolic series (linoleic, linolenic, clupanodonic, arachidonic, hydrocarpic, and chaulmoogric).
SEE: fat

folic acid

C₁₉H₁₉N₇O₆, a water-soluble B complex vitamin needed for DNA synthesis and amino acid metabolism. It is present in green leafy vegetables, beans, and yeast. It is used to treat megaloblastic and macrocytic anemias and to prevent neural tube defects (NTDs) and cardiovascular disease in adults. The U.S. Public Health Service recommends that all women of childbearing age who may become or are pregnant should consume 0.8 mg of folic acid daily to reduce their risk of having a child affected with spina bifida or other NTDs.
SYN: SEE: pteroylglutamic acid
SEE: neural tube defect
SYN: SEE: folate; SEE: vitamin B₉
CAS# 59-30-3

Folic acid should not be used to treat pernicious anemia (a vitamin B₁₂ deficiency) because it does not protect patients against the development of changes in the central nervous system that accompany this type of anemia.

folinic acid

C₂₀H₂₃N₇O₇, the active form of folic acid. It is used to counteract the effects of folic acid antagonists and to treat folic acid deficiency anemia.
CAS# 1492-18-8

formic acid

HCOOH, the first and strongest member of the monobasic fatty acid series. It occurs naturally in certain animal secretions, e.g., the sting of insects such as bees and ants, and in muscle, but it is also prepared synthetically.
CAS# 64-18-6

formiminoglutamic acid

C₆N₂O₄H₁₀, an intermediate product in the metabolism of histidine.
CAS# 816-90-0

free fatty acid

ABBR: FFA The form in which a fatty acid leaves the cell to be transported for use in another part of the body. FFAs are not esterified and may be unbound (not bound to protein). In the plasma, the nonesterified fatty acids released immediately combine with albumin to form bound free fatty acids.

free fetal nucleic acid

ABBR: ffNA Fetal RNA or DNA in blood or body fluids. It is used to determine the sex of the fetus (as in pregnancies in which X-linked inherited diseases are a concern) or to identify other genetically transmitted illnesses, e.g., trisomies.
SYN: SEE: cell-free fetal nucleic

fumaric acid

C₄H₄O₄, one of the organic acids in the Krebs cycle. It is used as a substitute for tartaric acid in beverages and baking powders.
CAS# 110-17-8

fuming nitric acid

Concentrated nitric acid (more than 86% nitric acid) that emits toxic fumes that cause choking if inhaled.
SEE: fumes

gadolinium-diethylenetriamine pentaacetic acid

ABBR: Gd-DTPA A radiographic contrast agent, used in magnetic resonance imaging to enhance the appearance of blood vessels.
Contrast agents containing gadolinium should not be given to patients with diminished renal function.

CAS# 86050-77-3

gallic acid

C₆H₂(OH)₃COOH, a colorless crystalline acid. It occurs naturally as an excrescence on the twigs of trees, esp. oaks, as a reaction to the deposition of gall wasp eggs. It is used as a skin astringent and in the manufacture of writing inks and dyes.
CAS# 149-91-7

gamma-aminobutyric acid

ABBR: GABA C₄H₉NO₂, the principal inhibitory neurotransmitter of the brain.
CAS# 56-12-2

gamma-linolenic acid

ABBR: GLA C₁₈H₃₀O₂, an essential fatty acid promoted by alternative medicine practitioners as a treatment for skin and inflammatory disorders, cystic breast disease, and hyperlipidemia.
CAS# 506-26-3

glucuronic acid

CHO(CHOH)₄COOH, an oxidation product of glucose that is present in the urine. Toxic products (salicylic acid, menthol, phenol) that have entered the body through the intestinal tract are detoxified in the liver by conjugation with glucuronic acid.
CAS# 6556-12-3

glutamic acid

HOOC·(CH₂)₂·CH(NH₂)·COOH, an amino acid formed in protein hydrolysis and an excitatory neurotransmitter in the central nervous system.
SYN: SEE: aminoglutaric acid
CAS# 617-65-2

glyceric acid

CH₂OH·CHOH·COOH, an intermediate product of the oxidation of fats.
CAS# 473-81-4

glycocholic acid

C₂₆H₄₃NO₆, a bile acid that hydrolizes to glycine and cholic acid.
CAS# 475-31-0

glycolic acid

C₂H₄O₃, an alpha-hydroxy acid derivative used to remove the outer layer of skin to rejuvenate its appearance.
CAS# 79-14-1

glyoxylic acid

C₂H₂O₃, an acid produced by the action of glycine oxidase on glycine or sarcosine.
CAS# 298-12-4

hippuric acid

C₆H₅CONHCH₂COOH, an acid formed and excreted by the kidneys. It is formed from the combination of benzoic acid and glycine. The synthesis takes place in the liver and, to a limited extent, in the kidneys.
CAS# 495-69-2

guanidoacetic acid

An acid formed in the liver, kidney, and other tissues. It is metabolized to form creatine.

hexafluorosilicic acid

SEE: Silicofluoride.

homogentisic acid

C₈H₈O₄, an intermediate product of tyrosine catabolism. It is found in the urine in alkaptonuria.
SYN: SEE: alkapton
CAS# 451-13-8

hyaluronic acid

ABBR: HA (C₁₄H₂₁NO₁₁)_n, an acid mucopolysaccharide found in the extracellular matrix of connective tissue that acts as a binding and protective agent. It is found in synovial fluid and in the vitreous and aqueous humors of the eye. Patients with osteoarthritis have elevated serum levels of HA.
SYN: SEE: hyaluronan
CAS# 9004-61-9

hydriodic acid

HI, an acid used in solution in various forms of chemical analyses.
SYN: SEE: hydrogen iodide
CAS# 10034-85-2

hydrochloric acid

HCl, an inorganic acid normally present in gastric juice. It destroys fermenting bacteria that might cause intestinal tract disturbances.
CAS# 7647-01-0

hydrocyanic acid

HCN, a colorless, extremely poisonous, highly volatile acid that occurs naturally in plants but is also produced synthetically. It acts by preventing cellular respiration. Hydrocyanic acid is used in electroplating, fumigation, and in producing dyes, pigments, synthetic fibers, and plastic. Exposure of humans to 200 to 500 parts of hydrocyanic acid per 1,000,000 parts of air for 30 min is fatal.
SYN: SEE: hydrogen cyanide
CAS# 74-90-8

hydrofluoric acid

HF, a corrosive solution of hydrogen fluoride in water. It can be used in dentistry to etch composites and porcelain surfaces and is used industrially to etch glass.
SEE: hydrogen fluoride
Exposure to the skin and aerodigestive tract causes severe burns with local necrosis and systemic manifestations resulting from disordered calcium and potassium metabolism. Treatments with calcium gluconate can be beneficial.

CAS # 7664-39-3

hydrorubeanic acid

SEE: Rubeanic acid.

hydrosulfuric acid

SEE: Hydrogen sulfide.

hydroxy acid

Any of the acids containing one or more hydroxyl (-OH) groups in addition to the carboxyl (-COOH) group, e.g., lactic acid, CH₃COHCOOH.

hydroxy-iminodiacetic acid

ABBR: HIDA A chemical that, when bound to radioactive technetium, is used to demonstrate the formation and flow of bile.
SEE: HIDA scan

hydroxycitric acid

C₆H₈O₈, an herbal extract promoted for the treatment of weight loss. Placebo-controlled studies have not found any benefit to the treatment.
CAS# 6205-14-7

hypochlorous acid

HClO, an acid used as a disinfectant, deodorant, and bleaching agent. It is usually used in the form of one of its salts.
CAS# 7790-92-3

imino acid

An acid formed as a result of oxidation of amino acids in the body.

inorganic acid

An acid containing no carbon atoms.
SYN: SEE: mineral acid

iocetamic acid

C₁₂H₁₃I₃N₂O₃, a radiopaque agent formerly used in cholecystography.
CAS# 16034-77-8

iopanoic acid

C₁₁H₁₂I₃NO₂, a radiopaque contrast medium used in radiographic studies of the gallbladder.
CAS# 96-83-3

keto acid

Any organic acid containing the ketone CO (carbonyl radical).

kynurenic acid

C₁₀H₇NO₃, a metabolite of tryptophan whose concentration increases during physical and emotional stress and blocks neurotransmission.
CAS# 492-27-3

lactic acid

C₃H₆O₃, an organic acid formed in muscles during anaerobic cell respiration in strenuous exercise. It is also formed during anaerobic muscle activity when glucose cannot be changed to pyruvic acid in glycolysis. It contributes to muscle aches and fatigue.
SYN: SEE: lactacid
CAS# 50-21-5,

levulinic acid

CH₃COCH₂CH₂COOH, an acid formed when certain simple sugars are acted on by dilute hydrochloric acid.
CAS# 123-76-2

lignoceric acid

C₂₄H₄₈O₂, a saturated, naturally occurring fatty acid present in certain foods, including peanuts. It is also found in wood tar, various cerebrosides, and in small amounts in most natural fats. The acid is also a by-product of lignin production.
CAS# 557-59-5

linoleic acid

C₁₈H₃₂O₂, an omega-6 fatty acid found in vegetables, nuts, grains, seeds, fruits and their oils. Oils rich in linoleic acid include (in descending order) safflower, sunflower, corn, soybean, and cottonseed.
CAS# 60-33-3

linolenic acid

C₁₈H₃₀O₂, an omega-6 fatty acid, thought to be cardioprotective. It reduces the production of cytokines and down-regulates serum cell adhesion molecules thought to be intermediates in atherosclerosis.
CAS# 506-26-3

lithic acid

An obsolete term for uric acid.

lysergic acid

C₁₆H₁₆N₂O₂, a crystalline acid derived from ergot. Its derivative, lysergic acid diethylamide (LSD), is a potent hallucinogen.
SEE: LSD
CAS# 82-58-6

lysophosphatidic acid

ABBR: LPA C₂₁H₄₁O₇P, an acid purified from the ascitic fluid of patients with ovarian cancer. LPA stimulates the growth of ovarian cancer and may be a useful screening test for the disease.
CAS# 22002-87-5

malic acid

C₄H₆O₅, an acid found in sour fruits such as apples and apricots and active in the aerobic metabolism of carbohydrates.
CAS# 6915-15-7

malonic acid

C₃H₄O₄, a dibasic acid formed by the oxidation of malic acid and active in the Krebs cycle in carbohydrate metabolism. Malonic acid is found in beets. Its inhibition of succinic dehydrogenase is the classic example of competitive inhibition.
CAS# 141-82-2

mandelic acid

C₈H₈O₃, a colorless hydroxy acid. Its salt is used to treat urinary tract infections.
SYN: SEE: phenylglycolic acid
CAS# 90-64-2

methacrylic acid

C₄H₆O₂, a colorless acid used to make methyl methacrylate.
CAS # 79-41-4

mineral acid

SEE: Inorganic acid.

monounsaturated fatty acid

ABBR: MUFA A fatty acid containing one double bond between carbon atoms. It is found in olive oil and is the predominant fat in the Mediterranean diet. It is thought to reduce low-density lipoprotein levels without affecting high-density lipoprotein levels.
SEE: Mediterranean diet

muriatic acid

A nontechnical term for hydrochloric acid.
CAS # 7647-01-0

n-3 fatty acid

SEE: Omega-3 fatty acid.

n-6 fatty acid

SEE: Omega-6 fatty acid.

nicotinic acid

SEE: Niacin.

nitric acid

HNO₃, a colorless, poisonous, fuming corrosive acid, widely used in industry and in chemical laboratories.
CAS# 7697-37-2

3-nitropropionic acid

C₃H₅NO₄, an inhibitor of mitochondrial energy generation through electron transport. It has been implicated in neurodegenerative movement disorders affecting the basal ganglia.
CAS# 504-88-1

nitrous acid

HNO₂, a weak acid chemical reagent used in biological laboratories.
CAS # 7782-77-6

nonvolatile acid

An acid, such as lactic acid or sulfuric acid, that accumulates in the body as a result of digestion, disease, or metabolism. It cannot be excreted from the body by ventilation but must be excreted by organs other than the lungs, e.g., by acidification of the urine.

nucleic acid

Any of the high-molecular-weight molecules that carry the genetic information crucial to the replication of cells and the manufacturing of cellular proteins. They have a complex structure formed of sugars (pentoses), phosphoric acid, and nitrogen bases (purines and pyrimidines). Most important are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).

octadecanoic acid

SEE: Stearic acid.

okadaic acid

C₄₄H₆₈O₁₃, a toxic acid found in shellfish. The toxin is produced by oceanic phytoplankton consumed by filter-feeding marine animals such as clams, crabs, and mussels and is the cause of diarrheal shellfish poisoning. Ingestion of these shellfish by humans results in profuse watery diarrhea.
CAS# 78111-17-8

oleic acid

C₁₈H₃₄O₂, a monounsaturated fatty acid found in most organic fats and oils.
CAS# 112-80-1

omega-3 fatty acid

ω-3 fatty acid Any of the long-chain polyunsaturated fatty acids found in the oils of some saltwater fish, and in canola, flaxseed, walnuts, and some vegetables. These acids include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linolenic acid (found in flaxseed and chia) can be metabolically converted to omega-3 fatty acids in the body.
SYN: SEE: n-3 fatty acid

omega-6 fatty acid

ω-6 fatty acid Any of the long-chain polyunsaturated fatty acids, such as linoleic acid and arachidonic acid. Linoleic acids are derived from vegetable oils; arachidonic acids, from animal fats.
SYN: SEE: n-6 fatty acid

omega-9 fatty acid

ω-9 fatty acid Any of the nonessential unsaturated fatty acids that have a double carbon bond in the ninth position from the end of their fatty acid tail. They include oleic acid (present in olive oil), stearic acid, and erucic acid.

organic acid

An acid containing the carboxyl radical, -COOH. Organic acids include acetic acid, formic acid, lactic acid, and all fatty acids.

orotic acid

C₅H₄N₂O₄, a crystalline acid occurring in milk. It is a precursor in the formation of pyrimidine nucleotides.
CAS# 65-86-1

osmic acid

SEE: Osmium tetroxide.

oxalic acid

C₂H₂O₄, the simplest dibasic organic acid. Its potassium or calcium salts occur naturally in rhubarb, wood sorrel, and other plants. It is the strongest organic acid and is poisonous. When properly diluted, it removes ink or rust stains from cloth. It is also used as a reagent.
CAS# 144-62-7

oxaloacetic acid

oxalacetic acid C₄H₄O₅, a product of carbohydrate metabolism resulting from oxidation of malic acid during the Krebs cycle. It may be derived from other sources.
CAS# 328-42-7

palmitic acid

C₁₆H₃₂O₂, a saturated fatty acid occurring as esters in most natural fats and oils.
CAS# 57-10-3

pantothenic acid

C₉H₁₇NO₅, an acid of the vitamin B complex, occurring naturally in yeast, liver, heart, salmon, eggs, and various grains. It is part of coenzyme A, which is necessary for the Krebs cycle and for conversion of amino acids and lipids to carbohydrates.
SYN: SEE: vitamin B₅
CAS# 137-08-6

para-aminobenzoic acid

ABBR: PABA NH₂C₆H₄COOH, an acid of the vitamin B complex, used as a dietary supplement, an antirickettsial drug, a reagent, and a sunscreen agent.
SYN: SEE: aminobenzoic acid
CAS# 150-13-0

para-aminohippuric acid

ABBR: PAH, PAHA C₉H₁₀N₂O₃, a derivative of aminobenzoic acid. The salt, para-aminohippurate, is used to test the excretory capacity of the renal tubules.
CAS# 61-78-9, 94-16-6 (sodium salt)

para-aminosalicylic acid

ABBR: PAS, PASA C₇H₇NO₃, a white or nearly white, practically odorless powder that darkens when exposed to air or light. It is a second-line drug used to treat multidrug-resistant tuberculosis.
SYN: SEE: aminosalicylic acid
CAS# 65-49-6

pectic acid

C₁₇H₂₄O₁₆, an acid derived from pectin by hydrolyzing its methyl ester group.

pentanoic acid

SEE: Valeric acid.

peptide nucleic acid

ABBR: PNA A synthetic nucleic acid analog in which natural nucleotide bases are linked to a peptide-like backbone instead of the sugar-phosphate backbone found in DNA and RNA. PNA has numerous uses in gene regulation, splicing, and therapy; in hybridization; and as a molecular diagnostic assay.

peracetic acid

C₂H₄O₃, a colorless, carcinogenic, corrosive acid with a pungent odor, used as a biocide and sterilant.
SYN: SEE: peroxyacetic acid

perchloric acid

HClO₄, a colorless unstable liquid compound. It is the highest oxygen-containing acid of chlorine, strong and dangerously corrosive.
CAS# 7601-90-3

peroxyacetic acid

SEE: Peracetic acid.

phenylglycolic acid

SEE: Mandelic acid.

phosphoric acid

An acid formed by oxidation of phosphorus. The phosphoric acids are orthophosphoric acid, H₃PO₄; pyrophosphoric acid, H₄P₂O₇; metaphosphoric acid, HPO₃; and hypophosphoric acid, H₄P₂O₆. The salts of these acids are phosphates. Orthophosphoric acid, a tribasic acid, is used as a 30% to 50% solution to etch enamel of teeth in preparation for bonding of resin dental restorations.
CAS# 7664-38-2 (orthophosphoric)

phosphorous acid

H₃PO₃, a crystalline acid formed when phosphorus is oxidized in moist air.
CAS# 13598-36-2

phytic acid

C₆H₁₈P₆O₂₄, a pale, water-soluble acid that is found in cereal grains and, if ingested, may interfere with the absorption of calcium and magnesium.
CAS# 83-86-3

picric acid

C₆H₂(NO₂)₃OH, a yellow crystalline powder that precipitates proteins and explodes when heated or charged. It is used as a dye and a reagent. Its salts are used in the Jaffé reaction (used to measure serum creatinine).
SYN: SEE: trinitrophenol
CAS # 88-89-1

poly DL lactic acid

SEE: Polyglactin.

polyglycolic acid

(C₂H₂O₂)_n, a polymer of glycolic acid anhydride units. It is used to manufacture surgical sutures, clips, and mesh.
CAS# 26009-03-0

polylactic acid

SEE: Polylactide.

propionic acid

C₃H₆O₂, a carboxylic acid present in sweat.
CAS# 79-09-4

pteroylglutamic acid

ABBR: PGA SEE: Folic acid

4-pyridoxic acid

C₈H₉NO₄, a crystalline acid that is the principal end product of pyridoxine metabolism, excreted in human urine.

pyroglutamic acid

C₅H₇NO₃, an amino acid that is a rare cause of anion gap metabolic acidosis, usually identified in children with endogenous glutathione metabolic disorders or in people who take acetaminophen chronically. Acidosis associated with pyroglutamic acid can be life-threatening.
SYN: SEE: 5-oxoproline; SEE: pyroglutamate

pyruvic acid

C₃H₄O₃, an organic acid that plays an important role in the Krebs cycle. It is an intermediate product in the metabolism of carbohydrates, fats, and amino acids. Its quantity in the blood and tissues increases in thiamine deficiency because thiamine is essential for its oxidation.
CAS# 127-17-3

quinic acid

C₇H₁₂O₆, a crystalline acid present in some plants, including cinchona bark, and berries.
CAS# 77-95-2

quinolinic acid

C₇H₅NO₄, a neurological excitotoxin that is produced by microglial cells and macrophages and is an agonist of N-methyl-d-aspartate (NMDA). It is an inflammatory pro-oxidant (a substance causing oxidative stress), damaging to neurons and glial cells.

retinoic acid

C₂₀H₂₈O₂, a metabolite of vitamin A used in the treatment of cystic acne.
CAS# 302-79-4

ribonucleic acid

SEE: RNA

ricinoleic acid

C₁₈H₃₄O₃, an unsaturated hydroxy acid making up about 80% of fatty acids in the glycerides of castor oil. It has a strong laxative action.
CAS# 141-22-0

rubeanic acid

H₂NCSCSNH₂, a histological stain for tissue copper.
SYN: SEE: dithiooxamide; SEE: ethanedithioamide; SEE: hydrorubeanic acid
CAS# 141-22-0

salicylic acid

C₇H₆O₃, a white crystalline acid derived from phenol used to make aspirin, as a preservative and flavoring agent, and in the topical treatment of some skin conditions such as warts and wrinkles.
SEE: chemical peeling
CAS# 69-72-7

salicyluric acid

C₉H₉NO₄, an acid found in the urine after ingestion of salicylic acid or its derivatives.

saturated fatty acid

A fatty acid in which the carbon atoms are linked to other carbon atoms by single bonds.
SEE: fatty acid; SEE: unsaturated fatty acid

silicic acid

Any of a family of acids containing silica, such as H₂SiO₃ (metasilicic acid), H₂SiO₄ (orthosilicic acid), or H₂SiO₇ (pyrosilicic acid). When silicic acid is precipitated, silica gel is obtained.
CAS# 10193-36-9

stearic acid

C₁₈H₃₆O₂, a monobasic fatty acid occurring naturally in plants and animals. It is used in the manufacture of soap and pharmaceutical products such as glycerin suppositories.
SYN: SEE: octadecanoic acid
CAS# 57-11-4

succinic acid

C₄H₆O₄, an intermediate in carbohydrate metabolism.
CAS# 110-15-6

sulfonic acid

Any of the organic compounds having the general formula SO₂OH, derived from sulfuric acid by replacement of a hydrogen atom.

sulfosalicylic acid

C₇H₆O₆S₃, a crystalline acid soluble in water or alcohol. It is used as a reagent for precipitating proteins, as in testing for albumin in urine.
CAS# 97-05-2

sulfuric acid

H₂SO₄, a colorless, corrosive, oily, viscous acid prepared from sulfur dioxide and used in many industrial processes and in clinical laboratories. Industrial accidents involving sulfuric acid through contact with skin or inhalation of aerosols are common.
CAS # 7664-93-9

sulfurous acid

H₂SO₃, an inorganic acid and a powerful chemical reducing agent used commercially, esp. as a bleach.
CAS # 7782-99-2

tannic acid

C₇₆H₅₂O₄₆, a mixture of digallic acid esters of d(+) glucose prepared from oak galls and sumac. It yields gallic acid and glucose on hydrolysis.
CAS# 1401-55-4

tartaric acid

C₄H₆O₆, an acid obtained from by-products of wine fermentation. It is widely used in industry in the manufacture of carbonated drinks, flavored gelatins, dyes, and metals. It is also used as a reagent. It is thought to be an allergen.
CAS# 526-83-0

taurocholic acid

C₂₆H₄₅NO₇S, a bile acid that hydrolyzes to cholic acid and taurine.
CAS# 81-24-3

teichoic acid

Any of the polymers found in the cell walls of some gram-positive bacteria, such as the staphylococci.

tranexamic acid

C₈H₁₅NO₂, an antifibrinolytic drug that has approx. 10 times the potency of, and more sustained activity than, aminocaproic acid. It is used to decrease bleeding time during surgical procedures. Loss of blood is decreased when this drug is used.
CAS# 1197-18-8

trans-fatty acid

The solid fat produced by heating liquid vegetable oils in the presence of hydrogen and certain metal catalysts. Partial hydrogenation changes some of the unsaturated bonds to saturated ones. The more trans-fatty acids in the diet, the higher the serum cholesterol and low-density lipoprotein cholesterol.

trichloroacetic acid

ABBR: TCA A drug used as a caustic to destroy certain types of warts, condylomata, keratoses, and hyperplastic tissue.

2,4,5-trichlorophenoxyacetic acid

SEE: 2,4,5-T.

undecylenic acid

(ŭn″dĕ″sĭ-lĕn′ĭk)

An antifungal drug used topically to treat tinea pedis (athlete's foot).
CAS# 112-38-9

unsaturated fatty acid

An organic acid in which some of the carbon atoms are linked to other carbon atoms by double bonds, thus containing less than the maximum possible number of hydrogen atoms, e.g., unsaturated oleic and linoleic acids as compared with the saturated stearic acid. Polyunsaturated fatty acids include linoleic acid and alpha-linoleic acid.
SEE: fatty acid; SEE: saturated fatty acid

uric acid

C₅H₄N₄O₃, a crystalline acid occurring as an end product of purine metabolism. It is formed from purine bases derived from nucleic acids (DNA and RNA). It is a common constituent of urinary stones and gouty tophi.

valeric acid

C₅H₁₀O₂, an oily fatty acid having a distinctly disagreeable odor, existing in four isomeric.
SYN: SEE: pentanoic acid
CAS# 109-52-4

valproic acid

ABBR: VPA C₈H₁₆O₂, an acid used to treat seizure disorders.
CAS# 99-66-1

vanillylmandelic acid

vanilmandelic acid ABBR: VMA C₉H₁₀O₅, a principal metabolic product of catecholamines. VMA makes up approx. 90% of the metabolites of the catecholamines epinephrine and norepinephrine and is secreted in the urine. People with pheochromocytoma produce excess amounts of catecholamines; therefore there are increased amounts of VMA in their urine.
CAS# 55-10-7

volatile acid

An acid produced from carbon dioxide (CO₂). It can be excreted by the body by ventilation (colloquially, “blowing off CO₂”).

xanthurenic acid

C₁₀H₇NO₄, an acid excreted in the urine of pyridoxine-deficient animals after they have been fed tryptophan.
SYN: SEE: 4,8-dihydroxyquinaldic acid
CAS# 59-00-7