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Néré seeds: a sustainable source for skin hydration
Link: Néré seeds: a sustainable source for skin hydration | Personal Care Magazine Feb 2016
By: Pauline Rouaud-Tinguely, David Boudier, Isabelle Cruz, Géraldine Bon, Céline Masson, Delphine Laporte, Solen Le Davadic, Brigitte Closs – Silab, France
Consumers and, increasingly, the global cosmetics market are currently focusing on hydrating skin care products containing natural ingredients of controlled origin.
Silab has responded to current market demands by creating a responsible, traced and controlled supply chain for néré seeds in Burkina Faso. Just as the tree has developed an effective strategy to maintain a constant supply of water in spite of an arid environment, Nerenyl® (INCI name: Saccharide Hydrolysate; SH), a natural, eco-designed and biomimetic cosmetic active ingredient, boosts skin hydration.
Two very important expectations of the cosmetics market are hydration and controlled origin1 and are therefore obligatory requisites for developing innovating active ingredients.
It is in this context that Silab began work on the néré, a characteristic and widespread tree in Burkina Faso that can withstand long periods of drought. Using the néré tree’s natural robustness and resistance to drought, Silab has developed a biomimetic ingredient dedicated to barrier function strengthening and hydration of dry skin. Rich in biosaccharides from néré seeds, Nerenyl® (INCI name: Saccharide Hydrolysate; SH) is obtained with a responsible, traced and controlled supply chain in Burkina Faso.
Description of the néré tree
Parkia biglobosa, better known as locust bean tree or néré, grows in the heart of Africa, in the Sahel-Sudan region. This robust tree can reach a height of 20 metres when fully grown between 30 and 50 years and some trees can reach the age of 100. The tree is characteristic of savannas and woodlands. Its wide crown is parasol-shaped and its roots ensure optimal water uptake. It easily adapts to depleted soil and can withstand long periods of drought, up to seven consecutive months.
The fruit of the néré grows as pods in clusters. The interior of the pods contains a yellow pulp that surrounds about 20 light brown seeds. Néré seeds ripen every year just before the rainy season begins in May (Fig. 1).
Figure 1: The néré tree in its habitat. © Personal Care Magazine
The néré tree is considered a genuine treasure by West African populations. A local saying is “everything, from the roots to the crown, contributes to the survival of mankind”. Several ancestral uses are known:
- Its seeds provide soumbala, a condiment used for cooking
- Its pods are used to decorate and protect the walls of dwellings
- Its roots are used in folk medicine.
Local action
Silab encountered the different partners of its project in the Kassena region in southern Burkina Faso. An association of harvesters in the village of Tiébéle in Nahouri province has enabled Silab to conduct its initial research on cosmetic potentials by providing samples in 2010 (Fig. 2). The abundance of néré seeds enables their use in cosmetics with no danger to biodiversity and local customs.
Figure 2: Silab’s local partners. © Personal Care Magazine
With the help of its Burkina Faso partner, Sama Bioconsult, Silab has developed a responsible, traced and controlled supply chain, compliant with precise and standardised specifications, according to which each step is subjected to strict controls:
- Traceability of trees: before each harvest, trees are marked in order to ensure the precise knowledge of the origin of seeds
- Monitoring harvests: harvesters are trained in good harvesting practices and packaging so as to preserve the trees’ resources and ecosystem and also to guarantee the quality and traceability of seeds. They also fill in a harvest notebook.
- Durability of the supply: a contract covering three sliding years stipulates Silab’s commitment to place a minimum yearly order, thereby stimulating local development.
- Securing supplies: a second association of harvesters is assisting in western Burkina Faso in order to duplicate this partnership model.
From harvest to packaging: a standardised process
Every morning of the course of two to three weeks, trained harvesters enter néré stands in Tiébelé, where young trees are preferentially harvested. Harvesters examine fruits to select the ideal pods, brown in colour, because these pods contain the ripest seeds and are the richest in active substances. Pods are harvested by hand, taking care not to damage or break branches in order to preserve the tree’s ecosystem.
After the operation finishes, harvesters return to the village where they begin the transformation of fruits, starting by drying the pods in the shade of mango trees for several days, followed by manually husking the pods to remove the seeds. The seeds are then crushed and sieved to separate them from the pulp. The pulp is recovered for food needs and the seeds are carefully selected to retain only those with optimal quality. They are then dried in the shade of mango trees for several days to evaporate residual moisture.
Finally, the seeds are packaged in bags with precise labels and placed in the village storehouse until sea shipment to France (Fig. 3).
Figure 3: Controlled steps, from harvest to packaging. © Personal Care Magazine
From néré seeds to the biomimetic and hydrating ingredient
After a validation of each batch of néré seeds received, Silab uses them in its manufacturing process. The use of a nondenaturing, aqueous phase process based on enzymatic bioengineering has led to the development of Nerenyl®, a natural, ecodesigned and biomimetic active ingredient, rich in biosaccharides.
The efficacy of this cosmetic active ingredient has been demonstrated in vitro by the study of two key biomarkers of skin hydration: aquaporins and hyaluronic acid. Aquaporins are genuine miniature irrigation canals in the membranes of epidermal cells that optimise the transport of water and solutes through the epidermis.2
Hyaluronic acid is the water reservoir of the skin because the main feature of this glycosaminoglycan is to capture and store water in its molecular structure.3 Tested on an innovative model of reconstructed epidermis (Silabskin® RE), Nerenyl (SH) stimulates the synthesis of these two biomarkers that are essential for skin hydration. The cosmetic benefits of SH in vivo were shown in a panel of women carefully chosen according to their age, their complexion radiance and the state of facial skin dryness.
Experimental method, results and discussion
A skin hydration booster
Hydration is essential for maintaining healthy skin4,5 In the concept of skin hydration it is important to reinforce the presence of hyaluronic acid to capture and retain water, as well as aquaporins to favour water flow through the skin. The effect of this Saccharide Hydrolysate (SH) on the synthesis of these two key biomarkers of hydration was analysed in vitro by immunolabelling and ELISA assay in a model of reconstructed epidermis, Silabskin RE. Tested at 0.25% on Silabskin RE, SH boosts the synthesis of aquaporins 3 by 27% and the secretion of hyaluronic acid by 62% (Fig. 4).
Figure 4: Effect of 0.10% and 0.25% saccharide hydrolysate on the synthesis of key markers of hydration in a model of reconstructed epidermis (Silabskin RE). © Personal Care Magazine
The capacity of SH to boost skin hydration was analysed in vivo by corneometry on a panel of 20 healthy female volunteers, mean age 53±8 years, with a dull complexion and facial skin with a tendency to dryness.
In comparison to the placebo and after 28 days of twice daily applications, SH formulated at 3% in an emulsion significantly increased skin hydration by 17.3% (P<0.05) in 90% of the volunteers.
Saving three days for restoring an optimal barrier function
The efficacy of SH on recuperation of the barrier function of the skin was determined in vivo by tewametry after a single aggression by successive strippings. The panel included 20 healthy female volunteers, mean age 56±8 years, with a dull complexion and facial skin with a tendency to dryness. Tested at 3% in an emulsion after 21 days of twice daily applications and in comparison to the placebo, SH restored more than 80% of a barrier effect in only 4 days, compared to 7 days for the placebo, i.e. a saving of 3 days and 43% of time (Fig. 5).
Figure 5: Effect of saccharide hydrolysate at 3% on the recuperation capacity of the barrier function after a single aggression by successive strippings. © Personal Care Magazine
These results were supported in vitro as an increase of epidermal differentiation and cell-cell cohesion, observed by immunolabelling on Silabskin RE with a deteriorated barrier function (data not shown).
Complexion radiance restored
The capacity of SH to restore complexion radiance in vivo was studied by a blind evaluation conducted by two trained experts on the same panel and in the same conditions as the corneometry study. In comparison to the placebo, SH formulated at 3% in an emulsion significantly improved important parameters involved in the overall determination of complexion radiance (Fig. 6).
Figure 6: Effect of saccharide hydrolysate formulated at 3% on complexion radiance
after 28 days of twice daily applications. © Personal Care Magazine
Conclusion
In order to respond to the two main expectations of the global cosmetics market, Silab investigated the hydrating capacity of néré, a characteristic tree of Burkina Faso, known to resist arid climates. The implementation of a responsible, traced and controlled supply chain has been built around three major aspects:
- A commitment with a network of partners including two associations of local harvesters (Pedatloga in Tiébelé and Kankéléfo in Kangala).
- A control of agronomy processes to ensure quality
- A total traceability from the plot of land to the cosmetic active ingredient.
From this supply, Silab has applied an eco-designed process to develop Nerenyl (INCI name: Saccharine Hydrolysate), a biomimetic ingredient rich in biosaccharides from néré seeds.
Tested on Silabskin RE, Nerenyl stimulates epidermal differentiation and cell cohesion at the same time as activating the synthesis of molecules indispensable for water flows in the epidermis. In vivo, the skin is rehydrated and recovery of an optimal barrier function after aggression is faster. Finally, complexion radiance is restored.
These properties make Nerenyl an excellent response to the needs of today’s women whose skin is dehydrated by their lifestyle. It is therefore recommended in all hydrating face and body care products that are claiming natural ingredients of controlled origin.
References
1 Ethicity 2013. Les Français et la consommation responsable 2013: la prise de conscience.
2 Verkman AS. More than just water channels: unexpected cellular roles of aquaporins. J Cell Sci 2005; 118 (15): 3225-32.
3 Robert L. Hyaluronan, a truly ‘youthful’ polysaccharide: Its medical applications. Pathol Biol (Paris) 2015; 63 (1): 32-4.
4 Rawlings AV, Harding CR. Moisturization and skin barrier function. Dermatol Ther 2004; 17 (Suppl 1): 43-8.
5 Verdier-Sévrain S, Bonté F. Skin hydration: a review on its molecular mechanisms. J Cosmet Dermatol 2007; 6 (2): 75-82.
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