Ajoene

April 15, 2019
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Ajoene is an unsaturated organosulfur compound found in small quantities (0.1%鈥�0.5%) in garlic. Its name comes from ajo, the Spanish word for garlic, so it is therefore pronounced a-ho-ene. Ajoene鈥檚 odor mimics that of whole garlic.

The natural product is a mixture of E- and Z-stereoisomers in a ratio of 鈮�1:2. The E-isomer is shown. According to at the Korea Food Research Institute (Gyeonggi鈥恉o),

Commercial products typically have an E/Z ratio of 鈮�2, with a range of 0.6鈥�2.5. . . . The E/Z ratio and yield depend on the polarity of the solvent system, reaction condition, and the type of fatty acids that are present during processing. It is known that the Z-isomer has a strong bioactivity compared to E-ajoene, while the E-isomer is more stable than the Z-isomer during storage.

For a relatively well-studied compound, little chemical and physical data for ajoene are available. Its hazard profile may also not be completely known.

Biologists and biochemists have long been interested in the potentially strong antimicrobial properties of ajoene, but neither purifying the natural product nor synthesizing it produced enough to work with. Recently, Thomas Wirth and colleagues at Cardiff University and Neem Biotech (both UK), seeking larger quantities of ajoene for drug research, of the compound.

The researchers鈥� five-step procedure begins with an alkyl dibromide and proceeds through three selenium-containing intermediates until the selenium moiety is oxidatively cleaved with hydrogen peroxide to produce ajoene. A thioether group was converted to sulfoxide in the same step. The authors expanded the original milligram-scale synthesis to make the compound in >100-g quantities.

In initial antibacterial testing, the synthetic product performed as well as ajoene isolated from garlic.

Don't forget to celebrate National Garlic Day on April 19!

础箩辞别苍别听hazard information

GHS classification*: not a hazardous substance or mixture

*Globally Harmonized System of Classification and Labeling of Chemicals.

础箩辞别苍别听fast facts

CAS Reg. No.92285-01-3
Empirical formulaC9H14OS3
Molar mass234.39 g/mol
AppearanceColorless liquid
Boiling point376 潞C (est.)
Water solubility0.3 g/L (est.)
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