Tea Tree Essential Oil: What is its Biochemical Composition?

The Tea tree, also known as tea tree or alternatively leafed melaleuca, is a shrub native to New Caledonia and Madagascar, but the leading producer today is Australia. The tea tree essential oil is extracted from the leaves of the tree Melaleuca alternifolia. According to the I.N.C.I. classification, it is named as "Melaleuca Alternifolia Leaf Oil".

It is obtained through hydrodistillation performedfrom the leaves. The principle involves heating a mixture of water and leaves to evaporate the volatile molecules and collect them following condensation. This method allows for the extraction of two substances, namely the hydrosol and the essential oil. The tea tree essential oilis a clear liquid ranging from colourless to pale yellow.It emits a scent that is simultaneously powerful, herbaceous, and fresh.

This essential oil offers numerous benefits. Notably, it helps to reduce symptoms associated with inflammation, fights against bacteria, and treats infections. It is for this reason that it has gained a certain reputation in aromatherapy as well as in dermo-cosmetics.

Depending on the extraction method as well as the plant cultivation conditions, the biochemical composition of tea tree essential oils can vary from one to another. In this article, we choose to focus on the main molecules present in the tea tree essential oil that we incorporate into some of our treatments. According to chromatographic analyses, the four predominant species are as follows.

• Terpinen-4-ol (30 - 48%)

  Belonging to the family of monoterpenic alcohols, this molecule imparts a characteristic floral and spicy scent. This compound is arecognised bactericide, particularly effective against two bacteria implicated in acne, S. Aureus and S. epidermidis. It also acts as a fungicide, virucide, and an immunomodulator.

• Gamma-terpinene (18 to 28%) and alpha-terpinene (7-8%)

  These mono-terpenes are antioxidants that inhibit the oxidation of low-density lipoproteins (LDL) as well as lipid peroxidation. To recall, lipid peroxidation is a chain mechanism of degradation of the constituents of cell membranes leading to the formation of unstable compounds called hydroperoxides, which then attack the constituents of the skin accelerating its ageing.

• Eucalyptol (approximately 15%)

  Also known as 1-8 cineole, this natural, colourless compound has a refreshing and spicy scent similar to camphor. It is recognised for its antifungal, anti-infective, bactericidal, antiviral and also expectorant properties. In the fight against bacteria responsible for acne, this compound plays a significant role. It causes a permeabilisation of bacterial membranes, thus facilitating the entry of more active bactericidal molecules from the essential oil, such as terpinen-4-ol, previously described.

• Paracymene (≤ 12 %)

  This organic compound, with a benzene structure (consisting of a 6-carbon cycle), has a herbaceous and spicy scent and is also recognised as an antibacterial agent.

Furthermore, this essential oil contains 1 to 2% of limonene, a terpene with the scent of lemon and orange. This molecule, with its anti-inflammatory properties, soothes redness and also fights against the bacteria responsible for acne. However, it is a recognised allergen.