Cinnamaldehyde

Cinnamaldehyde
IUPAC name (2E)-3-phenylprop-2-enal
Other names Cinnamic aldehyde; trans-cinnamaldehyde
Identifiers
CAS number	104-55-2 Y
PubChem	637511
ChemSpider	553117 Y
UNII	SR60A3XG0F Y
KEGG	C00903 Y
ChEBI	CHEBI:16731 Y
ChEMBL	CHEMBL293492 Y
IUPHAR ligand	2423
RTECS number	GD6475000
Jmol-3D images	Image 1
SMILES c1ccc(cc1)/C=C/C=O
InChI InChI=1S/C9H8O/c10-8-4-7-9-5-2-1-3-6-9/h1-8H/b7-4+ Y Key: KJPRLNWUNMBNBZ-QPJJXVBHSA-N Y InChI=1/C9H8O/c10-8-4-7-9-5-2-1-3-6-9/h1-8H/b7-4+ Key: KJPRLNWUNMBNBZ-QPJJXVBHBH
Properties
Molecular formula	C9H8O
Molar mass	132.16 g/mol
Appearance	Yellow oil
Density	1.05 g/ml
Melting point	-7.5 °C
Boiling point	248 °C
Solubility in water	Slightly Soluble
Viscosity	? cP at ?°C
Hazards
MSDS	External MSDS
R-phrases	R36 R37 R38
S-phrases	S26 S36
NFPA 704	2 2 0
Flash point	71 °C
Related compounds
Related compounds	Cinnamic acid
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cinnamaldehyde is the organic compound that gives cinnamon its flavor and odor.^[1] This pale yellow viscous liquid occurs naturally in the bark of cinnamon trees and other species of the genus Cinnamomum. The essential oil of cinnamon bark is about 90% cinnamaldehyde.

Structure and synthesis

Cinnamaldehyde was isolated from cinnamon essential oil in 1834 by Dumas and Péligot and synthesized in the laboratory by Chiozza in 1854.

The natural product is trans-cinnamaldehyde. The molecule consists of a phenyl group attached to an unsaturated aldehyde. As such, the molecule can be viewed as a derivative of acrolein. Its color is due to the π → π* transition: increased conjugation in comparison with acrolein shifts this band towards the visible.^[2]

Synthesis

Several methods of laboratory synthesis exist, but cinnamaldehyde is most economically obtained from the steam distillation of the oil of cinnamon bark. The compound can be prepared from related compounds like cinnamyl alcohol, (the alcohol form of cinnamaldehyde), but the first synthesis from unrelated compounds was the aldol condensation of benzaldehyde and acetaldehyde.

Biosynthesis

Cinnamaldehyde occurs widely and closely related compounds give rise to lignin. All such compounds are biosynthesized starting from phenylalanine, which undergoes conversion to cinnamoyl ester of coenzyme A.^[3]

Applications

As a flavorant

The most obvious application for cinnamaldehyde is as flavoring in items like chewing gum, ice cream, candy, and beverages range from 9 to 4900ppm(parts per million) (that is, less than 0.5%). It is also used in some perfumes of natural, sweet, or fruity scents. Almond, apricot, butterscotch, and other aromas may partially employ the compound for their pleasant smells. Cinnamaldehyde can be used as a food adulterant; powdered beechnut husk aromatized with cinnamaldehyde can be marketed as powdered cinnamon.^[4]

As an agrichemical

Cinnamaldehyde is also used as a fungicide.^[5] Proven effective on over 40 different crops, cinnamaldehyde is typically applied to the root systems of plants. Its low toxicity and well-known properties make it ideal for agriculture. Cinnamaldehyde is an effective insecticide, and its scent is also known to repel animals like cats and dogs.^[5] Cinnamaldehyde has recently been recognized as a very effective insecticide for mosquito larvae.^[6] As little as 29 ppm (parts per million) of cinnamaldehyde kills half of Aedes aegypti mosquito larvae in 24 hours.^[7][8]

As an antimicrobial

Another use for cinnamaldehyde is as an antimicrobial. Researchers from the University of Illinois at Chicago (who were funded by the Wm. Wrigley Jr. Company) have found that cinnamic aldehyde, when used in Big Red, prevented oral bacterial growth by more than 50 percent.^[9] It is especially effective against bacteria living at the back of the tongue, reducing anaerobic bacteria populations by about 43 percent.

As an anti-cancer agent

Recent research documents anti-cancer activity of cinnamaldehyde/cinnamic aldehyde observed in cell culture and animal models of the disease. Proliferation, invasion, and tumor growth were inhibited in a murine A375 model of human melanoma.^[10]

Miscellaneous uses

Cinnamaldehyde is also known as a corrosion inhibitor for steel and other ferrous alloys in corrosive fluids. It can be used in combination with additional components such as dispersing agents, solvents and other surfactants.

Derivatives of cinnamaldehyde

Numerous derivatives of cinnamaldehyde are commercially useful. Dihydrocinnamic alcohol (CAS#122-97-4), which occurs naturally but is produced by double hydrogenation of cinnamaldehyde, is used to confer the fragrances of hyacinth and lilac. Cinnamic alcohol (CAS#104-54-1) similarly occurs naturally and has the odor of lilac. Dihydrocinnamaldehyde (CAS#104-53-0) is produced by the selective hydrogenation of the alkene subunit. α-Amyl- and α-hexylcinnamaldehyde are important commercial fragrances, but they are not prepared from cinnamaldehyde.^[4]

Toxicology

Cinnamaldehyde is used in agriculture because of its low toxicity. It is however a skin irritant.

The level of coumarin detected in 'cinnamon' extracts and powders has concerned the German BfR.^[11]

References

1. ^ "Cinnamon". Transport Information Service. Gesamtverband der Deutschen Versicherungswirtschaft e.V.. http://www.tis-gdv.de/tis_e/ware/gewuerze/zimt/zimt.htm. Retrieved 2007-10-23. 
2. ^ Kozo Inuzuka, Bulletin of the Chemical Society of Japan Vol.34 , [No.11(1961)pp.1557-1560] http://www.journalarchive.jst.go.jp/english/jnlabstract_en.php?cdjournal=bcsj1926&cdvol=34&noissue=11&startpage=1557
3. ^ Boerjan, W.; Ralph, J. and Baucher, M., "Lignin Biosynthesis", Annu. Rev. Plant Biol. 2003. 54:519–46, 2003, 54, 519–46.doi:10.1146/annurev.arplant.54.031902.134938
4. ^ ^{a b} Karl-Georg Fahlbusch, Franz-Josef Hammerschmidt, Johannes Panten, Wilhelm Pickenhagen, Dietmar Schatkowski, Kurt Bauer, Dorothea Garbe, Horst Surburg “Flavors and Fragrances” in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a11_141
5. ^ ^{a b} "Cinnamaldehyde Use". PAN Pesticides Database. http://www.pesticideinfo.org/Detail_ChemUse.jsp?Rec_Id=PC33596. Retrieved 2007-10-23. 
6. ^ Cornelia Dick-Pfaff: Wohlriechender Mückentod, 19.07.2004
7. ^ "Cinnamon Oil Kills Mosquitoes". www.sciencedaily.com. http://www.sciencedaily.com/releases/2004/07/040716081706.htm. Retrieved 2008-08-05. 
8. ^ Cheng SS, Liu JY, Tsai KH, Chen WJ, Chang ST (July 2004). "Chemical composition and mosquito larvicidal activity of essential oils from leaves of different Cinnamomum osmophloeum provenances". J. Agric. Food Chem. 52 (14): 4395–4400. doi:10.1021/jf0497152. PMID 15237942. 
9. ^ "Popular Chewing Gum Eliminates Bacteria That Cause Bad Breath". Science Daily. http://www.sciencedaily.com/releases/2004/04/040401080031.htm. Retrieved 2009-09-22. 
10. ^ Cabello CM, Bair WB, Lamore SD, Ley S, Bause AS, Azimian S, Wondrak GT (January 2009). "The cinnamon-derived Michael acceptor cinnamic aldehyde impairs melanoma cell proliferation, invasiveness, and tumor growth". Free Radic. Biol. Med. 46 (2): 220–231. doi:10.1016/j.freeradbiomed.2008.10.025. PMC 2650023. PMID 19000754. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2650023. 
11. ^ High daily intakes of cinnamon: Health risk cannot be ruled out. BfR Health Assessment No. 044/2006, 18 August 2006, 15p