Bio inspired: COSSMA

Probiotics are well known for having a positive influence on health. Recently, scientists set their focus on postbiotics, their bioactive metabolites. Following the natural model with jojoba, scientists have achieved special results for dry skin.

Over the past ten years, scientists have made enormous progress in the understanding of the role of the microbial flora on health. This progress has led to the emergence of new therapeutic strategies based on the use of probiotics (defined as good bacteria), and more recently of postbiotics, a set of bioactive metabolites produced by probiotics. First related to the food industry and gut health, these microorganisms are now an area of research in the cosmetic industry. As one of the first companies, Silab became interested in the idea of transposing their beneficial effects to the skin. The company thus applied its expertise in mastering biotechnologies to bioguide the production of a natural postbiotic capable of addressing dry skin issues using a biomimetic approach.

Definition of pro- pre- and postbiotics

From the scientific discoveries on the human microbiota appeared the notions of probiotics, prebiotics and postbiotics. The knowledge of the precise terminology is very important for those who decide to work on these new concepts. Here are some key definitions, according to the literature and the World Health Organisation (WHO)^{1, 2}:

Probiotics are living microorganisms such as Lactobacilli or Bifidobacteria that, when administrated in sufficient quantities, have positive effects on the host’s health. They are more commonly known as “good bacteria”. It is very important to notice that a new term called paraprobiotic recently appeared and refers to dead or lysed microorganisms^3:

Prebiotics, literally “before the probiotic”, are non-digestible food in-gredients that selectively stimulate the growth and/or activity of “good bacteria” that may improve the health of the host;
Postbiotics, literally “after the probiotic”, are non-viable bacterial products or bioactive metabolites generated by probiotic microorganisms which bring benefits to the host.

First described and used for the treatment of intestinal disorders and general health, the concepts of probiotics and resulting postbiotics are now occurring in cosmetic industry⁴.

Effect on hydration of the skin of Caucasian volunteers (hands). Photo: Mélanie Coirier, Pauline Rouaud-Tinguely

From bio-inspiration to bioconversion

The most well-known probiotic belongs to the genus Lactobacillus. For the development of its new care product for dry skin, Silab’s research teams got specifically interested in Lactobacillus (L.) arizonensis a plant probiotic highly adaptable to desert climates. Indeed, it colonises jojoba, a shrub growing in extreme drought conditions, such as those of the Arizona desert. In order to ensure its survival, this good bacterial species (= probiotic) bio converts molecules of its host into bioactive metabolites, more commonly called postbiotics.

This ability to modify its metabolism to its environment provides it with a remarkable adaptation capacity and is the reason for its nickname of “natural metabolic engineer”. In this context, Silab’s team decided to use its historical expertise in biotechnologies and microbiota in order to reproduce in-house the specific natural environment of L. arizonensis. As expected, adding jojoba to the culture medium has mimicked the existing partnership between this bacterium and its substrate, thus allowing to bioguide the production of postbiotics rich in active molecules of cyclic polyols-type. Interestingly, these molecules were specifically identified by analytical laboratory as highly interesting due to their biomimetic action and particularly their ability to improve the quality of dry skin. Indeed, these cyclic polyols (identified through a metabolomics study by UPLC-MS/MS) are osmoregulating molecules known to play a fundamental role in adjusting osmotic pressure in plants. In drought conditions, they participate in maintaining the water status of the plant, in turn contributing to preserving its active metabolism. Such metabolites present a suitable molecular profile to treat skin dryness. Produced at industrial scale, the supernatant was used as natural raw material to concentrate active molecules by a patented process.

A natural solution

Dry skin is a common disorder that is marked by several symptoms including discomfort, excessive desquamation and the appearance of unsightly irregularities. These manifestations are the result of an alteration of the skin barrier function, caused by a number of factors (deterioration of the epidermal differentiation and cohesion, defect in the formation of the lipid cement and transepidermal water loss).

To determine the efficacy of the obtained active ingredient on dry skin, the company developed an in-house modelling mimicking dry skin, which enabled it to demonstrate the alteration of the skin barrier function and to prove that its active ingredient reactivates its integrity. More precisely, this was done by developing a novel in vitro 3D model of reconstructed epidermis subjected to a water stress, induced by incubation in an atmosphere of 40% humidity (vs. 82%) for three consecutive days. Through this modelling study, the postbiotic was proven to boost the mechanisms inherent in establishing an effective barrier function, thereby limiting the effects of epidermal dehydration, with the improvement of the differentiation process and epidermal cohesion and the activation of the lipid cement formation. These actions at the cell level all support cosmetics benefits.

Indeed, the results of in vivo tests demonstrated that after 28 days of twice-daily application to the face of Caucasian volunteers with dry skin, active molecules at 1% maintain the microbiota’s equilibrium and revitalises renewal of the cutaneous barrier. Hydration is improved (+16.2%) and complexion radiance is revived, as shown by increased reflection by the skin (+7.4%; P < 0.01). This dual hydrating/complexion booster effect was also seen on the face of Asian volunteers, to a significant degree.

Conclusion

With science as its driver for innovation, Silab combined its expertise in mastering natural products, biotechnologies and microbiota to develop a biosinspired, natural active ingredient. This patented biotech active (INCI name: Maltodextrin and Lactobacillus Ferment) is recommended in all care products for dry skin, available as a powder without preservatives (recommended amount: 0.1 to 1%) and compliant with international cosmetic regulations (Europe, United States, Japan, China, etc.).