Isoeugenol is a derivative of eugenol and has a chemical structure represented as C₁₀H₁₂O₂. It is used in perfumery for its sweet, spicy scent and can also be used as a flavoring in some food products. However, isoeugenol is also known to be a potential allergen, and therefore its use in cosmetics and skincare products is restricted in some nations.

The name describes the structure of the molecule.

• Iso- is a prefix indicating a particular arrangement of atoms within a molecule. Generally, "iso" indicates that a functional group is in a different position compared to the standard structure of the molecule.
• eugenol is an aromatic compound found in various plants like nutmeg, cinnamon, and cloves. It is known for its antioxidant and anti-inflammatory properties and is used in various products, such as food flavorings and in dentistry as an antiseptic.

Raw Materials Used in Production.

Isoeugenol is often derived from eugenol, which can be extracted from essential oils such as clove oil.

Step-by-step Summary of Industrial Chemical Synthesis Process.

• Extraction of Eugenol. Eugenol is extracted from essential oils, primarily clove oil, through distillation and purification processes.
• Isomerization of Eugenol. Eugenol is converted into isoeugenol through an isomerization process, which may involve catalysts and specific heat conditions.
• Purification. The isoeugenol is further purified through methods such as distillation to ensure the utmost purity of the product.

Form and Color.

Isoeugenol is generally an oily liquid, pale yellow in color.

What it is for and where

Cosmetics

It is a restricted ingredient as III/73  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: Phenol, 2-methoxy-4-(1-propenyl); (E)-2-methoxy-4-(prop-1-enyl)phenol;(trans-Isoeugenol); (Z)-2-methoxy-4-(prop-1-enyl)phenol;(cis-Isoeugenol)

Maximum concentration in ready for use preparation    b) 0,02 %

Other    (a) (b) The presence of the substance shall be indicated in the list of ingredients referred to in Article 19(1), point (g), when its concentration exceeds: — 0,001 % in leave-on products — 0,01 % in rinse-off products.

Perfuming. Unlike fragrance, which can also contain slightly less pleasant or characteristic odours, the term perfume indicates only very pleasant fragrances. Used for perfumes and aromatic raw materials.

Flavoring agent. The purpose of this ingredient is to modify the solution to impart a certain flavour. Natural flavouring extracts are rather expensive, so the cosmetic and pharmaceutical industries resort to synthesised substances that have sensory characteristics mostly similar to natural flavourings or are naturally equivalent. This ingredient is isolated through chemical processes or is synthesised from chemicals. It is also referred to as Aroma.

Commercial Applications.

Isoeugenol is widely used in perfumery and aromatherapy, as well as employed as a food flavorant and component in personal care products due to its spicy and floral notes.

Food Industry. Isoeugenol is used as a flavor in some food products due to its sweet, spicy taste.

Perfumery. It is valued in perfumes for its sweet, spicy aroma, and is found in many floral fragrances.

Cosmetics. It can sometimes be used in cosmetic and skincare products for its aromatic properties.

Chemical Industry. Isoeugenol can be used in the synthesis of other chemical compounds.

Dental Industry. It might be used in some dental products as a flavoring.

Safety

Isoeugenol is an ingredient generally considered safe (1), however, in some individuals it may be poorly tolerated depending on the amounts included in formulations (2).

• Molecular Formula  C₁₀H₁₂O₂
• Molecular Weight   164.20 g/mol
• CAS  97-54-1
• UNII    28FSR1NAY4
• EC Number   202-590-7
• DTXSID50872350

Synonyms:

trans-Isoeugenol

2-Methoxy-4-propenylphenol

References_____________________________________________________________________

(1) Api AM, Belsito D, Bhatia S, Bruze M, Calow P, Dagli ML, Dekant W, Fryer AD, Kromidas L, La Cava S, Lalko JF, Lapczynski A, Liebler DC, Miyachi Y, Politano VT, Ritacco G, Salvito D, Schultz TW, Shen J, Sipes IG, Wall B, Wilcox DK. RIFM fragrance ingredient safety assessment, isoeugenol, CAS Registry Number 97-54-1. Food Chem Toxicol. 2016 Nov;97S:S49-S56. doi: 10.1016/j.fct.2015.12.021. Epub 2015 Dec 23. PMID: 26723296.

(2) Johansen JD, Andersen KE, Menné T. Quantitative aspects of isoeugenol contact allergy assessed by use and patch tests. Contact Dermatitis. 1996 Jun;34(6):414-8. doi: 10.1111/j.1600-0536.1996.tb02244.x. 

Abstract. The clinical implications of sensitization to the fragrance material isoeugenol were studied in 19 subjects. Patch testing with serial dilutions of isoeugenol and a repeated open application test (ROAT) were performed. The minimum effect level under patch test conditions was below 0.01% isoeugenol in 4/19 (20%) of the test subjects. The ROAT was performed with a test solution of 0.2% isoeugenol in ethanol, which is the recommended maximum concentration used in perfumes, ethanol being applied as vehicle control. 4 weeks was the maximum exposure period. The upper arm was used as test site the 1st 14 days and the upper arm as well as the neck for the next 14 days. 12/19 (63%) of test subjects had a positive ROAT. 4 of the responders (33%) reacted beyond day 7, but none after day 14. Use testing on the neck 14 days did not add any further ROAT-positive cases, compared with testing on the upper arm. The sensitivity found on patch testing may be a guidance for the outcome of use tests with the same compound. In this study, all subjects with a positive use test to isoeugenol 0.2% in ethanol also demonstrated on patch testing a minimum effect level of 0.2% or lower. Data from serial dilution patch and use tests may contribute significant information to assessment of the relationship between patch test responses and clinical contact hypersensitivity, and thus the safety of allergens used in cosmetics.