Guaiazulene (1,4-dimethyl-7-isopropylazulene), bicyclic sesquiterpene, occurs naturally in essential oils of many aromatic and medicinal plants, such as Chamomile (Matricaria Chamomilla) and blue intratropic Callis.

Guaiazulene is a natural aromatic compound derived from the essential oil of certain plants, such as guaiac wood or chamomile flowers. It is a sesquiterpene hydrocarbon known for its deep blue color and is commonly used in cosmetics and skincare products due to its soothing, anti-inflammatory, and antioxidant properties. Guaiazulene is often added to creams, serums, and lotions formulated for sensitive or irritated skin, as well as after-sun products to soothe irritated skin.

Chemical Composition and Structure

It belongs to the class of aromatic compounds and is chemically a sesquiterpene hydrocarbon with the molecular formula C15H18. Its structure is similar to that of azulene, which gives it its name. Guaiazulene is known for its distinctive blue color, resulting from its unique electronic configuration, which sets it apart from common terpenes.

Physical Properties

Guaiazulene appears as blue crystals or a viscous liquid, insoluble in water but soluble in oils and organic solvents. It is known for its chemical stability and its ability to provide cosmetic formulations with a unique blue color. In addition to its use as a natural colorant, it has soothing properties that make it particularly useful in formulations for sensitive or damaged skin.

The name describes the structure of the molecule:

• Guaia- derives from "Guaiacum," a tropical tree from which guaiac oil is extracted. The term is often associated with compounds that have natural origins or are inspired by natural substances.
• -azulene refers to a class of organic compounds known as azulenes. Azulenes are known for their characteristic blue color and for their anti-inflammatory and soothing properties.

Description of Raw Materials Used in Production.

Guaiazulene is an organic compound primarily derived from guaiac oil, an essential oil extracted from the Guaiacum tree. It can also be sourced from chamomile (Matricaria chamomilla) and certain types of fungi.

Production Process

Guaiazulene is extracted through distillation of essential oils from natural sources such as guaiac wood and chamomile flowers. After extraction, it can be further purified to ensure its quality and stability. Some synthetic processes may be used to produce guaiazulene from azulene or other natural aromatic compounds. 

• Extraction: Guaiazulene is extracted from natural sources, primarily from the essential oil of Chamomilla recutita (chamomile) or other plants in the Asteraceae family. The collection of the plants is done sustainably to ensure the quality of the plant material.

• Distillation: After harvesting, the plants undergo a distillation process, usually through steam distillation. This method allows for the separation of essential oils, containing guaiazulene, from the solid parts of the plant.

• Purification: The obtained essential oil is further purified to isolate guaiazulene. This may include chromatography techniques or other separation methodologies to achieve a high-purity product.

• Quality Control: Once purified, guaiazulene undergoes quality control checks to verify its purity, stability, and functional properties. These checks may include chemical and microbiological analyses.

• Packaging: Finally, guaiazulene is packaged in appropriate containers for distribution and use in cosmetic and skincare products.

Commercial applications:

Cosmetics Industry. Guaiazulene is used in cosmetic products for its soothing and anti-inflammatory properties, especially in products designed for sensitive or irritated skin.

Skin Care. Often found in creams, lotions, and post-shave products to reduce redness, irritation, and calm the skin.

Use in Medicine. Can be used in some ointments and topical preparations to treat mild inflammations and skin irritations.

Safety. 

Generally considered safe for use in cosmetic and pharmaceutical products, but as with any ingredient, caution is advised in case of allergies or sensitivities.

Studies

It is an antioxidant, antifungal, antimicrobial, anti-inflammatory, anti-spasmodic, anti-ulcer, exerts anti-tumor activity and has relaxing properties (1).

Health and Safety Considerations

Safety in Use
Guaiazulene is considered safe for use in cosmetics and skincare products. It is widely used in formulations for sensitive skin due to its ability to reduce inflammation and irritation. It is well tolerated by the skin and is not known to cause sensitization or irritation.

Allergic Reactions
Allergic reactions to guaiazulene are extremely rare. However, as with any cosmetic product, a patch test is recommended before use, especially on sensitive skin.

Toxicity and Carcinogenicity
It has been extensively tested and used safely in cosmetic products without reports of significant adverse effects.

Environmental Considerations
Guaiazulene is derived from natural sources, and its production and extraction do not pose significant environmental risks. However, it is important that the plants from which it is extracted are harvested sustainably to avoid negative impacts on local ecosystems.

Regulatory Status
Guaiazulene is approved for use in cosmetic products by major regulatory authorities, including the European Union and the FDA in the United States. It is commonly used in a wide range of skincare and haircare products.

Guaiazulene other studies

• Molecular Formula: C₁₅H₁₈
• Molecular Weight: 198.309 g/mol
• CAS: 489-84-9
• EC Number: 207-701-2
• UNIII: 2OZ1K9JKQC
• Beilstein Registry Number:1365001
• MDL number MFCD00003811

Synonyms:

• 1,4-Dimethyl-7-isopropylazulene
• 7-Isopropyl-1,4-dimethylazulene
• 1,4-Dimethyl-7-(1-methylethyl)azulene
• 1,4-dimethyl-7-(propan-2-yl)azulene
• Vetivazulen
• Purazulen

(1) Higa T, Sakemi S. Guaiazulene derivatives and their methods of use. US Patent No. US 4755529 A. 1988:5–7.

Sleha R, Mosio P, Vydrzalova M, Jantovska A, Bostikova V, Mazurova J. In vitro antimicrobial activities of cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene against Mycoplasma hominis clinical isolates. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2014

Abstract. Aims: The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. Methods and results: The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC90 = 500 µg/mL) however was found to be the most effective. Carvacrol (MBC90 = 600 µg/mL) and eugenol (MBC90 = 1000 µg/mL) also possessed strong antimycoplasmal activity. Conclusions: The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections.