Ginger, an ancient antioxidant?

The ginger is a herbaceous plant from the Zingiberaceae family, native to Southeast Asia. It is often compared to the turmeric due to its large rhizomes from which it is possible to extract, through hydrodistillation, a pale yellow oil with a characteristic spicy scent.

Just like turmeric, the rhizomes of ginger contain numerous bioactive compounds with interesting cosmetic properties, which is why this ingredient is found in skincare and haircare products(INCI: Zingiber Officinale (Ginger) Root Extract).

Amongstthe molecules that make up ginger oil, it is estimated thataround forty possess antioxidant activity of varying degrees. However, the antioxidant properties of ginger extract are primarily derived from the gingerol and shogaol it contains. These two classes of molecules act via different mechanisms.

• Neutralising free radicals : Gingerol and shogaol are two cyclic molecules whose structures feature double bonds. These allow them to donate an electron to a free radical, thus completing its electronic structure. Upon receiving an electron from gingerol or shogaol, the free radical becomes a stable, non-reactive and non-damaging molecule for the body.

• Inhibiting Lipid Peroxidation : Several studies have shown that gingerol can inhibit the peroxidation of phospholipids, particularly induced by the enzyme xanthine oxidase responsible for generating free oxygen radicals such as the superoxide anion. This molecule also acts by reducing the activity of interleukin-1β (IL-1β), which is involved, among other things, in the increase of reactive oxygen species and the intensification of lipid peroxidation.

• Stimulating the activity of antioxidant enzymes : It has been demonstrated that gingerol and shogaol can enhance the activity of certain endogenous antioxidant enzymes. Indeed, gingerol acts on superoxide dismutase (SOD) and glutathione peroxidase (GPx), both of which are involved in the battle against oxidative stress.

  More specifically, SOD ensures the dismutation of superoxide anions O2.- into oxygen O2, while GPx catalyses the transformation of organic hydroperoxides before they can damage cells. Shogaol, on the other hand, is capable of modulating the activity of certain transcription factors, such as Nrf2, identified in the regulation of antioxidant enzymes.

Just like the rest of the body, the skin is sensitive to oxidative stress and needs to be protected from it. Oxidative stress refers to an imbalance between the quantities of antioxidants and free radicals in the cells. These free radicals can cause various skin damages and discomforts, and can notably be responsible forhyperpigmentation, premature ageing, or even melanomas. To avoid these, it is recommended to incorporate antioxidants such as ginger essential oil into your skincare routine.

Hair can also benefit from the antioxidant properties of theginger extract. Indeed, oxidative stress is equally harmful to it and can particularly weaken the hair bulb, and promote hair loss and split ends. The use of ginger essential oil can protect the hair from certain aggressions such as exposure to UV radiation or pollution, which generate oxidative stress.

How is ginger essential oil used in cosmetics?

Ginger is a versatile ingredient that can be incorporated into creams, masks, or serums intended for skin or hair use.

However, when it comes to theginger extract, it is strongly advised not to apply it undiluted to the skin or scalp as it may cause irritation. A dilution of 1 - 2% in sweet almond oil or jojoba oil is generally recommended.

Let us also remember that it is beneficial to perform a tolerance test before incorporating a new cosmetic active ingredient into one's routine. This is particularly true for ginger extract, which contains potentially allergenic compounds such as limonene and linalool.

• KORLAKUNTA J. N. & al. Comparative antioxidant and anti-inflammatory effects of [6]-gingerol, [8]-gingerol, [10]-gingerol and [6]-shogaol. Journal of Ethnopharmarcology (2010).

• PAZYAR N. Effects of ginger (Zingiber officinale) on skin conditions: A non quantitative review article. Journal of the Turkish Academy of Dermatology (2013).

• FANG J. & al. Activation of Nrf2 target enzymes conferring protection against oxidative stress in PC12 cells by ginger principal constituent 6-shogaol. Food and Function (2015).

• KRASTANOV A. & al. Composition and comprehensive antioxidant activity of ginger (Zingiber officinale) essential oil from Ecuador. Natural Product Communication (2015).