SKIN PROTECTION 175
A general rejuvenation effect was observed after 28 days of application with 75% of women declaring that their complexion is more radiant; 80% of women declaring that their skin is smoother; 65% of women declaring that their skin is firmer (Fig 2).
In vitro test results: Protecting the heart of the cells Exposure of the skin to sunlight accelerates skin ageing through a combination of several changes in the epidermis and dermis, in particular by directly affecting the cells’ DNA.
UV rays
UVB is absorbed mainly by the epidermis and the superficial dermis, while UVA penetrates much more deeply into the skin. UV rays, especially UVB, cause genetic mutations in cellular DNA. UVA rays are only very weakly absorbed by DNA bases, but they can excite cellular groups of atoms or photo-sensitisers, which will result in the formation of free radicals that can also cause DNA damage.
Blue light
Penetrating as far as the hypodermis, blue light generates a substantial creation of free radicals, which cause a release of epidermal inflammation mediators and also affect the DNA by damaging its bases.
Infrared light Infrared light rays are responsible for the sensation of heat, but also contribute to the creation of free radicals, which then damage the mitochondria. High intensities of light radiation kill most skin cells and those that are not killed are damaged. If they are damaged, cells become fragile and no longer function correctly.
Study of abasic cells To assess the effect of the enriched jasmine cell complex, Naolys decided to study apurinic/apyrimidinic (AP) or abasic sites, in the DNA of keratinocyte mitochondria. AP sites are one of the main DNA lesions formed during base excision repair. It is estimated that about 2x105 base lesions are generated per cell, per day. These lesions constitute a kind of vacant location in the DNA. The number of AP sites in cells can be a good
Number of AP sites (105 base pairs) Figure 2: Decrease in signs of ageing after 28 days.
indicator of DNA damage and of the proportion of repair as opposed to chemical damage. During radiation, clusters of abasic sites appear that are difficult to repair.
Study of mitochondrial DNA (Fig 3) At concentrations of 0.5%, 1% and 2.5%, a decrease of AP sites was observed after exposure to UVA/UVB respectively of 22%, 26% and 33% (compared to non-treated cells: +86%).
At concentrations of 0.5%, 1% and 2.5%, a
decrease of AP sites was observed after exposure to blue light respectively of 25%, 32% and 38% (compared to non-treated cells: +44%). At concentrations of 0.5%, 1% and 2.5%,
a decrease of AP sites was observed after exposure to infrared light respectively of 19%, 24% and 31% (compared to non- treated cells: +73%).
Protecting the fibres and the polysaccharides in the dermis: the extra-cellular matrix In the dermis, the extra-cellular matrix (ECM) is made up of various non-cellular components, and provides not only physical structure for the cellular components but also initiates the biomechanical and biochemical signals necessary for morphogenesis, differentiation and tissue homeostasis.
The extracellular matrix is composed of
water, polysaccharides and proteins; the two main types of macromolecules are the
Number of AP sites (105 base pairs)
proteoglycans and fibrous proteins, such as collagens, elastin, fibronectins and laminin synthesised by fibroblasts, cells in the dermis. In fact, the ECM is a highly dynamic structure that is constantly remodelling itself, both enzymatically and non- enzymatically. The ECM is responsible for the skin’s biochemical and mechanical properties, such as resistance to stretching and compression and elasticity; it is also responsible for its protection through a buffering effect that maintains extracellular homeostasis and water retention. We know that UVA light affects the extracellular matrix and breaks the fibres: the skin loses its firmness and elasticity. The formation of free radicals due to
UVA light and blue light (or visible light), causes an increase in MMP activity (the enzymes responsible for breaking down components in the ECM). According to recent studies, infrared light also causes collagen to breakdown.
Study of key components in the extra-cellular matrix
Study of key components in the extracellular matrix: collagen, hyaluronic acid and elastin with regard to their role in the skin’s firmness, flexibility and elasticity. Their breakdown and depletion cause slackening and wrinkles. These various studies of ECM components were carried out on a co-culture of fibroblasts and keratinocytes.
Number of AP sites (105 base pairs) Day 0 Day 28
-22% -26% -33%
Control UVA/UVB LD[JS+M] (0.5%)+
LD[JS+M] (1%)+
LD[JS+M] (2.5%)+
UVA/UVB UVA/UVB UVA/UVB Figure 3: Study of mitochondrial DNA. April 2020 PERSONAL CARE EUROPE
-25% -32% -38%
Control UVA/UVB LD[JS+M] (0.5%)+
LD[JS+M] (1%)+
LD[JS+M] (2.5%)+
UVA/UVB UVA/UVB UVA/UVB
-19% -24% -31%
Control UVA/UVB LD[JS+M] (0.5%)+
LD[JS+M] (1%)+
LD[JS+M] (2.5%)+
UVA/UVB UVA/UVB UVA/UVB
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