38 Acrolein Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colourless liquid with a piercing, disagreeable, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat breaking down into acrolein. It is produced industrially from propylene and mainly used as a biocide and a building block to other chemical compounds, such as the amino acid methionine. Acrolein is used as an etherification agent in the preparation of modified food starches. Acrolein is an herbicide and algicide used in water treatment. It is produced by microorganisms, e.g. Clostridium perfringens. Acrolein is a relatively electrophilic compound and a reactive one, hence its high toxicity. It is a good Michael acceptor, hence its useful reaction with thiols. It forms acetals readily, a prominent one being the spirocycle derived from pentaerythritol, diallylidene pentaerythritol. Acrolein participates in many Diels-Alder reactions, even with itself. Via Diels-Alder reactions, it is a precursor to some commercial fragrances, including lyral, norbornene-2-carboxaldehyde, and myrac aldehyde. Acrolein is toxic and is a strong irritant for the skin, eyes, and nasal passages. The main metabolic pathway for acrolein is the alkylation of glutathione. The WHO suggests a 'tolerable oral acrolein intake' of 7.5 mg/day per kilogram of body weight. Although acrolein occurs in French fries, the levels are only a few micrograms per kilogram. 107-02-8 7847 C3H4O 56.026220 Greenish-yellow when impure -87.7°C 52°C 212 mg/mL at 25°C Oral (L121) ; inhalation (L121) ; dermal (L121) Acrolein rapidly and irreversibly binds to lysine moieties and sulfhydryl groups found on many cellular molecules forming thiol ethers. By this mechanism acrolein can bind to messenger compounds to produce direct cytotoxic effects or secondary effects from interrupted cell signaling pathways. Perturbation of inflammatory responses in bronchial epithelial cells was demonstrated by direct action of acrolein on the inhibitor of nuclear factor kappa-B (IκB) kinase, which inhibits activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcription factor and suppresses interleukin 8 (IL-8) production. Rapid binding of acrolein to neural receptors in the corneal and nasal mucosa results in rapid depolarization of the associated neurons to produce ocular and nasal irritation. Acrolein also binds rapidly to glutathione, which may be inhibitory to the enzyme glutathione peroxidase and result in a lower level of cellular protection against oxygen radical toxicity. Further, the adduction of glutathione generates GS-propionaldehyde, which produces oxygen and possibly hydroxy radicals via cytosolic aldehyde dehydrogenase. Acrolein inhibits thioredoxin and thioredoxin reductase, which disrupts the cellular thiol redox balance necessary for cell survival. It interferes with normal reverse cholesterol transport by high density lipoprotein (HDL) by modifying specific sites in apolipoprotein A-I. Acrolein also inhibits aldehyde dehydrogenases and activates the transient receptor potential cation channel. (L121, A84, A85, A86) Acrolein can be absorbed though oral, inhalation, or dermal routes. In the liver and kidneys, acrolein forms conjugates with glutathione, cysteine, N-acetylcysteine, and/or thioredoxin. Acrolein can also be transformed into acrylic acid by liver cytosol or microsomes, or it can be oxidized to glycidaldehyde by lung or liver microsomes. Acrolein metabolites are excreted in the urine. (L121) LC50: 130 ppm over 30 minutes (Inhalation, Rat) (T21) LD50: 562 mg/kg (Dermal, Rabbit) (T22) LD50: 46 mg/kg (Oral, Rat) (T22) LD50: 30 mg/kg (Subcutaneous, Rat) (T22) High levels of acrolein (>7 mg/m3) cause injury to lungs after short term exposures. 10 ppm for an adult human. (L138) 3, not classifiable as to its carcinogenicity to humans. (L135) Acrolein is used as a pesticide to control algae, weeds, bacteria, and mollusks. It is also used to make other chemicals, such as polyester resin, polyurethane, propylene glycol, acrylic acid, acrylonitrile, and glycerol. Small amounts of acrolein can be formed when trees, tobacco, other plants, gasoline, and oil are burned. (L121) Acute Inhalation: 0.003 ppm (L134) Intermediate Inhalation: 0.00004 ppm (L134) Intermediate Oral: 2 mg/kg/day (L134) Acrolein is a severe pulmonary irritant and lachrymatory agent. Breathing large amounts of acrolein damages the lungs and could cause death. (L121, L122) Ingestion of acrolein causes stomach irritation, vomiting, stomach ulcers and bleeding. Breathing acrolein may cause eye watering, burning of the nose and throat and a decreased breathing rate. (L121) 2009-03-06T18:57:58Z 2014-12-24T20:20:56Z http://en.wikipedia.org/wiki/acrolein C01471 15368 T-2-NONENAL-CMPD D000171 Acrolein 24 true C=CC=O C3H4O InChI=1S/C3H4O/c1-2-3-4/h2-3H,1H2 InChIKey=HGINCPLSRVDWNT-UHFFFAOYSA-N 56.0633 56.02621475 Exogenous Liquid -0.01 HMDB41822 CHEMBL721 7559