Chemical Properties
Methylglyoxal (MG, C3H4O2) is also known as 2-oxopropanal, pyruvaldehyde, pyruvic aldehyde, 2-ketopropionaldehyde, acetylformaldehyde, propanedione, or propionaldehyde, which is a clear yellow slightly viscous liquid with a pungent odor which polymerizes readily and forms a variety of cyclic and acyclic structures. It is faintly acidic to litmus. The solubility of methylglyoxal is more than 10 g/100 mL water at 17°C. In water, MG is present mostly in the mono and dihydrate forms, while non hydrated MG is only present in traces.
Description
Methylglyoxal is an organic compound formed as a side-product of several metabolic pathways. It has been proved to be an intermediate in the metabolism of acetone and its derivatives. It is produced to insure every cell's health, which is used commonly as a reagent in organic synthesis, as a flavoring agent, and in tanning. However, the most important application is in pharmaceuticals. Methylglyoxal is found in all honeys, especially in manuka honey, in which it has strong antibacterial and antiviral property. Methylglyoxal is transferred into the honey where it remains stable. Dietary Methylglyoxal found in Manuka Honey is resistant to heat, light, body fluids and enzymatic activity. This property makes MGO Manuka Honey superior to any other honey. Its anti-cancer potential has been already demonstrated in human body and it has proved to be effective to eradicate most cancer types.
Sources
Many food products, beverages, water, rain, clouds, fog water, and urban atmosphere as well as cigarette smoke represent exogenous sources of methylglyoxal. The origins of MG in food and beverages are sugars, the products of the Maillard reaction, lipids and microorganisms formed during industrial processing, cooking, and prolonged storage. In vivo Methylglyoxal can be formed in many enzymatic and nonenzymatic pathways. Enzymatic pathways include reactions catalyzed by triosephosphate isomerase, cytochrome P450 2E1, myeloperoxidase, and aminooxidase, whereas nonenzymatic pathways include decomposition of dihydroxyacetone phosphate (DAP), the Maillard reaction, oxidation of acetol, and lipid peroxidation.
References
https://en.wikipedia.org/wiki/Methylglyoxal
https://pubchem.ncbi.nlm.nih.gov/compound/880#section=Top
http://www.cancertreatmentsresearch.com/methilglyoxal/
Description
Methylglyoxal (MG) is a highly reactive a-dicarbonyl
compound that is primarily generated endogenously during
glycolytic pathways (glucose and fructose metabolism) in cells
and exogenously due to autoxidation of sugar, degradation of
lipids, and fermentation during food and drink processing.
Methylglyoxal polymerizes readily; it is hygroscopic and
incompatible with strong oxidizing agents and bases. Methylglyoxal
may be present as a free molecule in the diet or bound
to biological materials, such as proteins, and as advanced glycation
end products (AGEs), which are poorly absorbed.
Methylglyoxal has been indicated in pathological events associated
with hyperglycemia in both type 1 and type 2 diabetes
and in other diabetic complications as either a direct toxin or as
a precursor for AGEs. In animal studies, MG has been shown to
induce tumorigenesis, but has also been reported as a tumoristatic
agent. Methylglyoxal has been identified as the dominant
antibacterial constituent of manuka honey.
Chemical Properties
Pyruvaldehyde has a characteristic, pungent, stinging odor with a pungent, caramellic, sweet flavor.
Chemical Properties
clear yellow to yellow-brown solution
Occurrence
Reported found in the dry distillate of Manilla copal. Also reported found in apple juice, orange juice, celery root, rutabaga, tomato, wheaten bread, white bread, roasted and raw turkey, cognac, roasted barley, beer, cocoa, coffee and roasted pecans.
Uses
Used in organic synthesis, as a flavoring agent, and in tanning
leather. Commercial formulation is available as a 30% aqueous
solution. No safety concern at current levels of intake when
used as a flavoring agent.
Uses
Organic synthesis, as of complex chemical com-
pounds such as pyrethrins, tanning leather, flavor-
ing.
Uses
Methylglyoxal solution has been used:
- to assess glyoxalase 1 (GLO1) enzymatic activity
- as an advanced glycation end (AGE) forming agent for the preparation of albumin in vitro
- to regulate anxiety like behavior in mice
- to induce peritoneal fibrosis in rats
- to study the chromatographic retention characteristics of organic chemicals and metal DNA adducts
- for intraplantar injection in mice to investigate peripheral and central components of methylglyoxal (MG)-transient receptor potential ankyrin 1 (TRPA1)-adenylyl cyclase 1 isoform (AC1) pathway
Definition
ChEBI: A 2-oxo aldehyde derived from propanal.
Preparation
By distilling a dilute solution of dihydroxyacetone from calcium carbonate; by oxidation of acetone with selenium dioxide; by heating dihydroxy acetone with phosphorus pentoxide; by warming isonitroso acetone with diluted H2SO4.
Taste threshold values
Taste characteristics at 0.1%: sweet, caramellic with a dairy creamy nuance
General Description
Clear yellow slightly viscous liquid with a pungent odor. Yellowish-green vapors. Faintly acidic to litmus.
Air & Water Reactions
Water soluble.
Reactivity Profile
Methylglyoxal polymerizes readily. Methylglyoxal is hygroscopic. Methylglyoxal is incompatible with strong oxidizing agents and bases. Methylglyoxal is an aldehyde. Aldehydes are frequently involved in self-condensation or polymerization reactions. These reactions are exothermic; they are often catalyzed by acid. Aldehydes are readily oxidized to give carboxylic acids. Flammable and/or toxic gases are generated by the combination of aldehydes with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Aldehydes can react with air to give first peroxo acids, and ultimately carboxylic acids. These autoxidation reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). The addition of stabilizers (antioxidants) to shipments of aldehydes retards autoxidation.
Fire Hazard
Literature sources indicate that Methylglyoxal is nonflammable.
Flammability and Explosibility
Non flammable
Environmental Fate
Methylglyoxal production and use as a chemical intermediate
and flavoring agent may result in its release to the environment
through various waste streams. If released into water, MG is not
expected to adsorb to suspended solids and sediment based on
the estimated Koc. Volatilization from water surfaces is not
expected to be an important fate process based upon the estimated
Henry’s Law constant. If released to soil, MG is expected
to have very high mobility based upon an estimated Koc of 1
determined from the structure estimation method. Hydrolysis
is not expected to be an important environmental fate process
since this compound lacks functional groups that hydrolyze
under environmental conditions.
Methylglyoxal serves as a substrate for the isozymes E1, E2,
and E3 of human aldehyde dehydrogenase. Oxidation of MG
by these isozymes generated pyruvate. Methylglyoxal is
a partially oxidized compound obtained from the tropospheric
oxidation of numerous hydrocarbons, of both biogenic and
anthropogenic origin. If released to the air, an estimated vapor
pressure of 27 mm Hg at 25 ℃ indicates MG will exist solely as
a vapor in the atmosphere. Vapor-phase MG will be degraded
in the atmosphere by reaction with photochemically produced
hydroxyl radicals; the half-life for this reaction in air is estimated
to be 30 h. Methylglyoxal absorbs light at wavelengths
>290 nm and, therefore, is susceptible to direct photolysis by
sunlight; half-lives of 2–4 h have been reported.
Purification Methods
Commercial 30% (w/v) aqueous solution is diluted to about 10% and distilled twice, taking the fraction boiling below 50o/20mm Hg. (This treatment does not remove lactic acid). [Beilstein 1 IV 3631.]
Toxicity evaluation
Endogenously formed MG modifies arginine and lysine residues
in proteins that form AGEs, which have been associated
with diabetic complications and some neurodegenerative
diseases. In different cell lines, MG treatment has been shown to induce apoptosis as measured by nuclear fragmentation and
apoptotic body formation, indicating an increase in apoptosis.
At the mitochondrial level, exogenous MG is highly toxic as it
promotes proliferation, swelling, and membrane derangement.
In both in vitro and in vivo studies, MG treatment has been
shown to significantly reduce antioxidant enzymes and elevate
reactive oxygen species that lead to oxidative stress-mediated
cell death. Genotoxicity has been observed in both in vivo
and in vitro studies, as MG is capable of binding to cellular
macromolecules and forming DNA adducts.
