Gentisic acid is a dihydroxybenzoic acid. It is a derivative of

benzoic acid Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which ...

and a minor (1%) product of the metabolic break down of

aspirin Aspirin () is the genericized trademark for acetylsalicylic acid (ASA), a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and inflammation, and as an antithrombotic. Specific inflammatory conditions that aspirin is ...

, excreted by the kidneys. It is also found in the African tree ''

Alchornea cordifolia ''Alchornea cordifolia'' is a shrub or small tree distributed throughout tropical Africa, it can grow up to 8 metres tall. The plant is used in traditional African medicine. Common name is the Christmas bush. Chemical constituents The leaves, ...

'' and in

wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...

Production

Gentisic acid is produced by carboxylation of

hydroquinone Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a ''para' ...

.Hudnall, Phillip M. (2005) "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Wiley-VCH, Weinheim. . :C₆H₄(OH)₂ + CO₂ → C₆H₃(CO₂H)(OH)₂ This conversion is an example of a

Kolbe–Schmitt reaction The Kolbe–Schmitt reaction or Kolbe process (named after Hermann Kolbe and Rudolf Schmitt) is a carboxylation chemical reaction that proceeds by treating phenol with sodium hydroxide to form sodium phenoxide, then heating sodium phenoxide wi ...

. Alternatively the compound can be synthesized from

salicylic acid Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...

via

Elbs persulfate oxidation The Elbs persulfate oxidation is the organic reaction of phenols with alkaline potassium persulfate to form '' para''-diphenols. The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents. ...

Reactions

In the presence of the enzyme gentisate 1,2-dioxygenase, gentisic acid reacts with

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

to give maleylpyruvate: :2,5-dihydroxybenzoate + O₂

\rightleftharpoons

maleylpyruvate

Applications

As a

, gentisic acid is readily oxidised and is used as an

antioxidant Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...

excipient An excipient is a substance formulated alongside the active ingredient of a medication. They may be used to enhance the active ingredient’s therapeutic properties; to facilitate drug absorption; to reduce viscosity; to enhance solubility; to i ...

in some

pharmaceutical Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the ...

preparations. In the laboratory, it is used as a sample matrix in

matrix-assisted laser desorption/ionization In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy-absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of b ...

(MALDI)

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used ...

, and has been shown to conveniently detect peptides incorporating the boronic acid moiety by MALDI.

References

Cited sources

* {{DEFAULTSORT:Gentisic Acid Hydroquinones Salicylic acids Dihydroxybenzoic acids Phenolic human metabolites Human drug metabolites