The benefits of ectoine for the skin.

Ectoine could also function as ananti-inflammatory. In a study, Andreas BILSTEIN and his team sought to investigate the potential benefit of a topical application of ectoine in cream form on 65 patients suffering from atopic dermatitis. The patients applied the ectoine cream and a "control" cream (another anti-inflammatory cream) to the lesions twice a day for 28 days.

After 7 and 28 days, the treated skin areas were evaluated using SCORAD (Scoring Atopic Dermatitis) and IGA (Investigator's Global Assessment) scores. The SCORAD measures the severity of atopic dermatitis for each of the five symptoms (erythema, papules, crusting and oozing, excoriation and lichenification), assigning them an intensity score from 0 to 3, and then adding them together to get the total sum. The IGA measures the severity of the condition by scoring from 0 (no inflammatory sign of atopic dermatitis) to 5 (very severe erythema and papulation/infiltration with oozing/crusting)

Researchers found that after the treatment application, the average total SCORAD decreased from 7.51 to 5.32, and to 3.77 at the final visit, proving more effective compared to the "control" cream, which decreased from a score of 7.55 to 5.74, and to 4.45 at the last visit. Regarding the IGA score, it decreased from 2.82 to 2.20, and to 1.57 at the final visit, again proving more effective compared to the "control" cream, which decreased from a score of 2.82 to 2.31, and to 1.86 at the last visit.

Topical application of ectoine thus reduces the inflammatory symptoms of atopic dermatitis. It has been demonstrated that ectoine stabilises the membrane structures of human epithelial cells, including epidermal keratinocytes. It thereby prevents the triggering of pro-inflammatory signal cascades, necessary for the upregulation of inflammatory molecules, such as ICAM-1 on the surface of human keratinocytes. This adhesion molecule is a characteristic of inflammatory skin diseases, such as psoriasis and atopic dermatitis. Overall, this clearly indicates that ectoine possesses anti-inflammatory properties.

An experiment conducted by Vladislav O. SOLDATOV and his team aimed to assess the reparative activity of ectoine using a thermal burn model in rats. In 30 male rats, two thermal burns were inflicted, one of which was treated with a topical application of an ectoine gel (500 mg) for 7 days, while the other served as a control. On day 8, skin samples from the burn area were taken for morphological examination.

The ectoine observation group revealed an almost complete recovery of the skin. On the surface of the burn, a crust is visualised, beneath which lies a thin layer of newly formed epidermis. In the underlying layers of the dermis, a fibrous skeleton is made up of mature collagen fibres, which meet all the morphological and functional criteria necessary for the formation of connective tissue. Finally, numerous lymphocytes were detected. In the control group, researchers observed the presence of oedema and necrosis on the wounds, with less effective healing.

The precise mechanisms by which ectoine impacts wound healing have not yet been elucidated. However, it can be hypothesised that ectoine works by stimulating cellular proliferation through lymphocytes, enabling better skin repair. Furthermore, lymphocytes can secrete growth factors and cytokines that promote the migration of cells involved in tissue repair, such as fibroblasts and endothelial cells. These mechanisms could therefore be implicated in the enhancement of wound healing following topical application of ectoine.

In order to measure the hydrating power of ectoine, Hansjuergen DRILLER and other researchers applied an emulsion containing 0%, 2%, and 5% ectoine to the forearms of five volunteers twice daily for a week. The transepidermal water loss (TEWL) was artificially increased, then determined using a TEWAmeter before and after the application of ectoine, while the skin's water content was determined using a corneometer before the application and after the final application.

In the short term, ectoine in an emulsion protects the skin against dehydration, and produces a higher water content than the control. On the final day, we observe 40 AU of hydration (arbitrary unit) without ectoine and 60 AU with ectoine. The results also show that ectoine maintains a degree of skin hydration higher than that of untreated skin or skin treated with a placebo. The water content of the skin after 24 hours of dehydration is 50 AU without ectoine and 60 AU with ectoine. In the long term, after eight days of application, hydration has significantly increased up to 200% compared to skin treated with a placebo and remained constant until the end of the test period.

This effect can be explained by the ability of ectoine to form complexes with water molecules. Indeed, water molecules organise themselves into clusters around ectoine molecules and form hydrogen bonds with them. This property is vital for halophilic bacteria living in salty environments that synthesise it, as it allows them to limit their water loss induced by the salinity of the environment. Therefore, it is this property that would allow ectoine to maintain skin hydration and increase the water content of the skin.

In 2020, the team led by Hsin-Ling YANG aimed to demonstrate a depigmenting effect of ectoine. To do this, they irradiated human keratinocytes with UVA to stimulate the production of melanin, pre-treated cells with low concentrations of ectoine (0.5 - 1.5 μM) and tested for various depigmenting and anti-melanogenic parameters.

Keratinocytes exposed to UVA were stimulated for their proopiomelanocortin (POMC) and also the melanotrope-alpha hormone (α-MSH) derived from POMC. Indeed, melanin production is regulated by α-MSH, which is produced from POMC. They found that pre-treatment with ectoine downregulated the expression of POMC and α-MSH.

Furthermore, in cells previously stimulated with α-MSH, it is observed that those exposed to increasing concentrations of ectoine (100 - 400 μM) show a significant decrease in their percentage of melanin and tyrosinase, with a reduction of melanin by 85% for 400 μM of ectoine.

It is hypothesised that ectoine operates in this manner through a reduction in the activity of tyrosinase, an enzyme essential for the synthesis of melanin, and a decrease in α-MSH, which results in a reduction in the amount of melanin and therefore a lightening effect.