Turmeric and skin: its natural anti-inflammatory effects.

The turmeric is a plant native to India and Southeast Asia. Botanically, it is a perennial plant belonging to the Zingiberaceae family. It has been used for centuries in traditional Chinese and Indian medicines, particularly for its anti-inflammatory properties that come from its biochemical composition. In the West, however, its uses were only discovered from the 17th century onwards.

If turmeric is so highly praised for its anti-inflammatory effects, it's thanks to the curcumin it contains. Also known as diferuloylmethane, this molecule is a yellow pigment that contributes to giving turmeric powder its warm hues. It is also involved in numerous biological processes, particularly regulating certain inflammatory signalling pathways.

For instance, curcumin is capable of inhibiting the NF-kB and JAK/STAT pathways, which are responsible for the increase in the production of pro-inflammatory cytokines. These inflammation mediators are small proteins secreted by cells in response to various stimuli. In terms of the immune response, they allow communication between immune cells and guide the response depending on the nature of the detected signal. Among the pro-inflammatory cytokines regulated by curcumin, we can mention interleukins 1α and 6 (IL-1α and IL-6) as well as the tumour necrosis factor (TNF-α).

Furthermore, based on various experiments conducted on curcumin, this molecule is not only capable of reducing the production of pro-inflammatory cytokines, but also of inhibiting the induction of the cyclooxygenase-2 (COX-2) membrane protein. This plays a role in the production of prostaglandins. Prostaglandins are molecules belonging to the class of prostanoids. These are neurotransmitters with various physiological effects and contribute to the development of inflammatory responses such as the vasodilation of blood vessels and pain.

Finally, curcumin inhibits the activity of the 5-lipoxygenase (LOX-5), an enzyme primarily expressed by leukocytes. LOX-5 is responsible for the generation of leukotrienes, known to be potent lipid mediators of inflammation. These play a significant role in allergic reactions.

The various mechanisms of inflammation in which curcumin plays a part make turmeric a friend to those suffering fromacne, eczema, psoriasis or more generally from irritations and itching. In the case of acne, the application of a cream enriched with turmeric can, for example, reduce the inflammation of the sebaceous glands, exacerbated by the bacterium Cutibacterium acnes. Turmeric also alleviates the redness and itching characteristic of atopic dermatitis and reduces sensitivity to pain.

• SUDHEER A. & al. Antioxidant and anti-inflammatory properties of curcumin. Advances in Experimental Medicine and Biology (2007).

• LEE S. J. & al. Aromatic-turmerone inhibits α-MSH and IBMX-induced melanogenesis by inactivating CREB and MITF signaling pathways. Archives of Dermatological Research (2011).