Saffron to accelerate skin healing?

The saffron is a spice extracted from the flowers of Crocus sativus, whose cultivation in ancient Greece has been evidenced by frescoes dating back to 1,600 BC. It is also said that Cleopatra incorporated it into what is considered today as the first toilet water. Named "kyphi", it later became a sacred incense for the Egyptian pharaohs. The cultivation of saffron then spread throughout the Mediterranean basin before being disseminated in Western Europe.

In the 19th century, saffron cultivation in Europe declined due to harsh winters and fungal diseases such as the saffron rust. It even disappeared during the Second World War due to the proliferation of other crops, such as beetroot and potato. In France, saffron was cultivated again in the 1980s. Today, the main regions of cultivation are Iran, Greece, Morocco, Spain, and India.

When the skin is damaged, following an injury or due toacne for instance, it responds by initiating several defence mechanisms to combat inflammation. Immune cells, such as macrophages, are first recruited to the injury site. They eliminate cellular debris and bacteria present in the wound, thus promoting an environment conducive to tissue regeneration. As inflammation subsides, the phase of cellular proliferation begins. Fibroblasts, specialised cells, multiply and migrate towards the wound. They are responsible for the production of collagen, a protein essential for the formation of scar tissue, as well as other components of the extracellular matrix.

Simultaneously, the process ofangiogenesis is initiated, meaning that new blood vessels are formed from the existing vessels damaged by the injury. The endothelial cells within the blood vessels respond to the damage by dividing and migrating towards the injured area. They then form new blood vessels, which allows for the delivery of nutrients, oxygen, and growth factors necessary for healing.

Finally, the healing process continues with the re-epithelialisation, or the regeneration of the epidermis. This occurs via the activation of keratinocytes, the constitutive cells of the epidermis. The keratinocytes located at the periphery of the wound multiply and migrate towards the injury zone, interacting with the components of the extracellular matrix. During their migration, they differentiate, meaning they undergo morphological and molecular changes to transform into mature epithelial cells. These differentiated cells form a new layer of epidermis, similar to the one that existed before the injury.

Saffron has long been used for its therapeutic virtues. Whether taken orally or applied topically when incorporated into a cream, it aids skin healing through various mechanisms. Studies have notably shown that the kaempferol contained in saffron works by increasing the activity of the vascular endothelial growth factor (VEGF), whose role is to trigger the formation of new blood vessels (angiogenesis). In fact, a study conducted on mice showed that a loss of activity of this growth factor present in keratinocytes delayed wound healing.

Furthermore, saffron extract works by increasing the production ofinterleukin-6 (IL-6). Although they are considered pro-inflammatory cytokines, it is widely accepted that they possess regenerative and anti-inflammatory activities. Indeed, IL-6 initiates certain mechanisms related to skin healing, and induces the migration and proliferation of keratinocytes.

Finally, saffron extract possesses moisturising properties, which are essential for ensuring proper wound healing. Indeed, when we get injured, a wound tends to be red and painful: the skin can burn, itch or feel tight. It is then necessary to hydrate it well so that it can heal correctly. A study showed that saffron extract had a certain hydrating capacity and that the daily application of a cream enriched with 3% saffron could reduce transepidermal water loss (TEWL) by 7% and increase overall skin hydration by 8% in 8 weeks. It was hypothesised that the moisturising properties of saffron come from the polysaccharides in its composition, considered as humectant agents. Indeed, their molecular structure promotes the absorption and retention of water, which prevents the skin from dehydration.

Whilst genuine, the healing properties of saffron extract remain limited and this ingredient will only have an effect on minor wounds and everyday small cuts. In the event of a serious injury or infection of a wound, it is imperative to consult a doctor as soon as possible.

The healing virtues of saffron extract can also be utilised to lessen the acne lesions or the purple stretch marks. Indeed, there are numerous treatments available on the cosmetic market aimed at acne-prone skin or formulated to prevent or reduce the appearance of stretch marks.

However, it should be noted that scientific studies investigating the healing properties of saffron extract have been conducted in vitro, and not on individuals with actual wounds, suffering from acne or having stretch marks. Therefore, further research is still necessary and it is appropriate to exercise caution regarding the effect of saffron extract on these types of lesions.

• NAVEED A. & al. Moisturizing effect of stable cream containing Crocus sativus extracts. Pakistan Journal of Pharmaceutical Sciences (2014).

• BUTTERWECK V. & al. Saffron flower extract promotes scratch wound closure of keratinocytes and enhances VEGF production. Planta Medica (2017).