What is "Curcuma Longa Rhizome Powder" and what is its use?

Belonging to the Zingiberaceae family, the Curcuma longa is a perennial herbaceous plant that primarily thrives in the humid climates of certain Asian and African countries such as India, Bangladesh, Pakistan, and Madagascar. Today, there are more than 700 species of Curcuma.

In recent years, the anti-cancer potential of Curcuma longa has been the subject of several studies. Experiments have indeed demonstrated a reduction in tumour development in mice when administered with an extract of Curcuma longa. This property is attributed to curcumin, a major compound of this plant, identified as a chemopreventive agent. Furthermore, the European Medicines Agency classifies Curcuma longa as an effective plant for relieving difficult digestion, to be consumed in the form of herbal tea.

Identified under the I.N.C.I. name "Curcuma Longa Rhizome Powder", turmeric powder is obtained by mechanically grinding the dried roots of the plant. This spicy-scented powder is quite fine, of a yellow-orange colour, and is used exclusively in dispersion in cosmetic formulas.

The benefits of this compound for the skin and hair are due to its main component, the curcumin. This is a low molecular weight polyphenol with the raw formula C21H20O6, first characterised in 1910.

Firstly, curcumin possesses antioxidant properties. It protects cell membranes from peroxidative damage caused by free radicals. As a reminder, these are extremely reactive compounds that degrade the lipids and proteins of the skin, accelerating its ageing. Lipid peroxidation is a free radical-mediated chain reaction, leading to the damage of cell membranes and thus the disruption of the hydrolipidic film. Curcumin inhibits this peroxidation thanks to its antioxidant action against free radicals. It thus maintains the integrity of the skin barrier and protects skin cells from premature ageing.

Curcumin is also recommended for damaged skin prone to redness and irritated scalps due to its anti-inflammatory properties. A study compares its activity to non-steroidal anti-inflammatory drugs such as aspirin, but without the side effects. Indeed, like aspirin, curcumin inhibits the induction of COX-2, an inflammatory membrane protein that releases prostaglandins with arolein disease pathology.

Turmeric powder also possesses antiseptic and antibacterial properties, which help to limit the growth of bacteria involved in acne, such as P. acnes. Furthermore, its previously described anti-inflammatory properties promote faster healing and thus limit the phenomenon of post-inflammatory hyperpigmentation.

Finally, researchers have demonstrated the activity of curcumin in inhibiting the activity of PhK, a protein associated with psoriasis.

Due to its colouring properties, turmeric powder is found in certain hair and makeup products such as plant-based hair dyes, tinted face powders, and eyeshadows. Its antioxidant virtues make it a valuable ally in combating the appearance of wrinkles; it thus forms part of some serums and face creams.

• PHAN D. Compositions and methods of treatment for skin conditions using extracts of turmeric. United States Patent (2003).

• MENON V. P. Antioxidant and anti-inflammatory properties of curcumin. Advances in Experimental Medicine and Biology (2007).

• MAHESHWARI R. K. & al. Beneficial role of curcumin in skin diseases. Advances in Experimental Medicine and Biology (2007).