Cinnamaldehyde is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with the formula(C9H8O) C₆H₅CH=CHCHO. Occurring naturally as predominantly the ''trans'' (''E'') isomer, it gives

cinnamon Cinnamon is a spice obtained from the inner bark of several tree species from the genus '' Cinnamomum''. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, breakf ...

its flavor and

odor An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense ...

. It is a

phenylpropanoid The phenylpropanoids are a diverse family of organic compounds that are synthesized by plants from the amino acids phenylalanine and tyrosine. Their name is derived from the six-carbon, aromatic phenyl group and the three-carbon propene tail of ...

that is naturally synthesized by the shikimate pathway. This pale yellow,

viscous The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the in ...

liquid occurs in the

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...

of cinnamon

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s and other species of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

'' Cinnamomum''. The

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

of cinnamon bark is about 90% cinnamaldehyde. Cinnamaldehyde decomposes to styrene because of oxidation as a result of bad storage or transport conditions. Styrene especially forms in high humidity and high temperatures. This is the reason why

contains small amounts of styrene.

Structure and synthesis

Cinnamaldehyde was isolated from cinnamon essential oil in 1834 by

Jean-Baptiste Dumas Jean Baptiste André Dumas (14 July 180010 April 1884) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights (relative atomic masses) and molecular weights by measuring ...

and Eugène-Melchior Péligot and synthesized in the laboratory by the Italian chemist

Luigi Chiozza is a fictional character featured in video games and related media released by Nintendo. Created by Japanese video game designer Shigeru Miyamoto, Luigi is portrayed as the younger fraternal twin brother and sidekick of Mario, Nintendo's masc ...

in 1854. The natural product is ''

trans Trans- is a Latin prefix meaning "across", "beyond", or "on the other side of". Used alone, trans may refer to: Arts, entertainment, and media * Trans (festival), a former festival in Belfast, Northern Ireland, United Kingdom * ''Trans'' (fil ...

''-cinnamaldehyde. The molecule consists of a benzene ring attached to an unsaturated aldehyde. As such, the molecule can be viewed as a derivative of

acrolein Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, 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 ...

. Its color is due to the π → π* transition: increased conjugation in comparison with acrolein shifts this band towards the visible.

Biosynthesis

Cinnamaldehyde occurs widely, and closely related compounds give rise to

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity a ...

. All such compounds are biosynthesized starting from

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amin ...

, which undergoes conversion. The biosynthesis of cinnamaldehyde begins with deamination of L-phenylalanine into cinnamic acid by the action of phenylalanine ammonia lyase (PAL). PAL catalyzes this reaction by a non-oxidative deamination. This deamination relies on the MIO prosthetic group of PAL. PAL gives rise to ''trans-''cinnamic acid. In the second step, 4-coumarate–CoA ligase (4CL) converts cinnamic acid to cinnamoyl-CoA by an acid–

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

ligation. 4CL uses ATP to catalyze the formation of cinnamoyl-CoA. 4CL effects this reaction in two steps. 4CL forms a hydroxycinnamate–AMP anhydride, followed by a nucleophile attack on the carbonyl of the acyl adenylate. Finally, Cinnamoyl-CoA is reduced by NADPH catalyzed by CCR (cinnamoyl-CoA reductase) to form cinnamaldehyde.

Preparation

Several methods of laboratory synthesis exist, but cinnamaldehyde is most economically obtained from the

steam distillation Steam distillation is a separation process that consists in distilling water together with other volatile and non-volatile components. The steam from the boiling water carries the vapor of the volatiles to a condenser; both are cooled and re ...

of the oil of cinnamon bark. The compound can be prepared from related compounds such as cinnamyl alcohol, (the

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

form of cinnamaldehyde), but the first synthesis from unrelated compounds was the aldol condensation of

benzaldehyde Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful. It is a colorless liquid with a characteristic almond-like odor. ...

and

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the ...

; this process was patented by Henry Richmond on November 7, 1950.

Applications

As a flavorant

The most obvious application for cinnamaldehyde is as

flavoring A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the g ...

in chewing gum,

ice cream Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as ...

candy Candy, also called sweets (British English) or lollies (Australian English, New Zealand English), is a confection that features sugar as a principal ingredient. The category, called ''sugar confectionery'', encompasses any sweet confection, i ...

, e-liquid and beverages; use levels range from 9 to 4,900 parts per million ( ppm) (that is, less than 0.5%). It is also used in some

perfume Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent ...

s of natural, sweet, or

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

y scents.

Almond The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genu ...

apricot An apricot (, ) is a fruit, or the tree that bears the fruit, of several species in the genus '' Prunus''. Usually, an apricot is from the species '' P. armeniaca'', but the fruits of the other species in ''Prunus'' sect. ''Armeniaca'' are al ...

, butterscotch, and other

aroma An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sens ...

s may partially employ the compound for their pleasant smells. Cinnamaldehyde can be used as a

food adulterant An adulterant is caused by the act of adulteration, a practice of secretly mixing a substance with another. Typical substances that are adulterated include but are not limited to food, cosmetics, pharmaceuticals, fuel, or other chemicals, that ...

; powdered

beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engl ...

nut

husk Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective ...

aromatized with cinnamaldehyde can be marketed as powdered

. Some breakfast cereals contain as much as 187 ppm cinnamaldehyde.

As an agrichemical

Cinnamaldehyde has been tested as a safe and effective insecticide against mosquito

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e. A concentration of 29 ppm of cinnamaldehyde kills half of ''

Aedes aegypti ''Aedes aegypti'', the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its l ...

'' mosquito larvae in 24 hours. * Trans-cinnamaldehyde works as a potent fumigant and practical repellant for adult mosquitos. It also has

antibacterial An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

and

antifungal An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as ...

properties.

Miscellaneous uses

Cinnamaldehyde is a corrosion inhibitor for

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistan ...

and other

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductili ...

s. It is believed to form a protective film on the metal surface.

Derivatives

Numerous derivatives of cinnamaldehyde are commercially useful. Dihydrocinnamyl alcohol (3-phenylpropanol) occurs naturally but is produced by double

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

of cinnamaldehyde. It has the fragrances of hyacinth and lilac. Cinnamyl alcohol similarly occurs naturally and has the odor of lilac but can be also produced starting from cinnamaldehyde. Dihydrocinnamaldehyde is produced by the selective hydrogenation of the alkene subunit. α-Amylcinnamaldehyde and α-hexylcinnamaldehyde are important commercial fragrances, but they are not prepared from cinnamaldehyde. Hydrogenation of cinnamaldehyde, if directed to the alkene, gives hydrocinnamaldehyde.

Toxicology

Cinnamaldehyde is used in agriculture because of its low toxicity, but it is a skin irritant. Cinnameldahyde may cause allergic contact stomatitis in sensitised individuals, however allergy to the compound is believed to be uncommon.

DNA repair

Cinnamaldehyde is a dietary antimutagen that effectively inhibits both induced and spontaneous

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, m ...

s.Shaughnessy DT, Schaaper RM, Umbach DM, DeMarini DM. Inhibition of spontaneous mutagenesis by vanillin and cinnamaldehyde in ''Escherichia coli'': Dependence on recombinational repair. Mutat Res. 2006 Dec 1;602(1-2):54-64. doi: 10.1016/j.mrfmmm.2006.08.006. Epub 2006 Sep 26. PMID: 16999979; PMCID: PMC2099251 Experimental evidence indicates that cinnamaldehyde induces a type of

DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA d ...

in the bacterium ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...

'' and in human cells that elicits recombinational DNA repair that then reduces spontaneous mutations. In mice,

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

induced chromosome aberrations were reduced when cinnamaldehyde was given orally to the mice after X-ray irradiation,Sasaki YF, Ohta T, Imanishi H, Watanabe M, Matsumoto K, Kato T, Shirasu Y. Suppressing effects of vanillin, cinnamaldehyde, and anisaldehyde on chromosome aberrations induced by X-rays in mice. Mutat Res. 1990 Apr;243(4):299-302. doi: 10.1016/0165-7992(90)90146-b. PMID: 2325694 perhaps due to cinnamaldehyde stimulated

DNA repair DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA d ...

References

External links

GMD MS Spectrum
{{Transient receptor potential channel modulators Alkene derivatives Conjugated aldehydes Flavors Fungicides Plant toxin insecticides Phenylpropanoids Corrosion inhibitors Xanthine oxidase inhibitors Cinnamon