The role of antioxidants in cosmetic formulations
In the world of beauty and well-being, the word “antioxidant” often comes up. But what are really these actives? And what are they used for?
One of the theories used to explain aging is the oxidative stress theory, in which very reactive molecules linked to oxygen damage our most vital molecules, such as DNA or cell membrane components, at all times. These highly reactive molecules are called free radicals or reactive oxygen species (ROS). Although ROS can be harmful, they are also essential because of their important biological functions, such as cellular signalling. However, they are produced in excess during oxidative stress and our natural antioxidant system is then incapable of maintaining the balance. These molecules cause significant damage and are the cause of several chronic diseases.
At the skin level, oxidation is one of the major phenomena responsible for cellular aging. It damages skin cells of the epidermis and dermis, and contributes to their degeneration. Antioxidants are therefore valuable allies to help the skin fight against the free radicals produced during oxidative stress.
As the name suggests, antioxidants are oxidation inhibitors. In cosmetics, an antioxidant can be used for two main reasons :
to protect the product’s formula from oxidation, in particular from the rancidity of fatty substances (oils, butters, waxes, etc.);
to help the skin cells to fight free radicals and control premature skin aging factors.
What causes oxidation?
The skin is constantly exposed to different types of aggressions: they can be biological, chemical or physical. The concentration of reactive oxygen species dramatically increases after exposure to UV (Kaur et al., 2007), pollution (Lupo, 2001), tobacco or chemicals. Stress, tiredness or bad lifestyle choices can also lead to excess radicals in the skin.
UV rays :
Chronic UV exposure from the sun is the predominant factor responsible for premature skin aging. UV-induced alterations are added to the signs of intrinsic, genetically programmed aging, this phenomenon is called photo-aging. The so-called photo-aged skin has particular characteristics and is distinguishable from photo-protected areas. It is deeply wrinkled, spotted, reddened, dehydrated, rigid and fragile. Collagen and elastin fibres, which constitute the extracellular matrix of the dermis, are disorganized and degraded, leaving skin tissues subject to inflammation.
Only 5% of UVB radiation (230–320 nm) reaches the surface of the Earth and the rays can penetrate inside the skin as deep as 160–180 μm, and 10% of these rays reach the dermis. These rays, although present in small quantities, are the most damaging due to the large amount of energy they carry. On the other hand, 90 to 95% of UVA rays reach the surface of the Earth and they can penetrate as deep as 1000 μm in the skin—20 to 30% reach the dermis
UVA rays are less damaging than UVB rays, but they are constantly present in our environment and their exposure generates an oxidative stress in the skin via the excessive production of ROS in cutaneous cells and more particularly the singlet oxygen, the peroxide and the superoxide anion (Murray et al., 2008, Agar et al., 2004 in Matsui et al., 2009, Hillion, 2006). UVB are also at the root of ROS production in the skin (Jurkiewicz and Buettner, 1994 in Xu and Fisher, 2005, Zang et al., 1997 in Zang et al., 2004, Afaq et al., 2005 in Afaq and Mukhtar, 2006, Nishigori, 2006; Yaar and Gilchrest, 2007).
Pollution is everywhere: in the atmosphere, inside our homes, at the fingertips of smokers, etc. Millions of particles are deposited daily on the skin, which ends up being asphyxiated. This pollution film which forms on the surface of the epidermis deteriorates the balance of the skin by aggressing and stifling it. The hydrolipidic film, which is crucial for the good functioning of the cells, is also affected. The effects on skin beauty and health are numerous: pollution amplifies oxidative reactions, intensifies brown spots, accentuates the depth of wrinkles, increases the loss of skin radiance and promotes inflammatory reactions.
Ozone is an extremely powerful oxidizing agent formed in the troposphere (high atmosphere) through a complex series of reactions involving sunlight and oxygen. Closer to home, the combustion of fossil fuels for energy production or transportation contributes to the increasing concentration of ozone in the air in which we live.
Ozone initiates intracellular oxidative stress by forming ozonides and hydroperoxides. This mechanism of oxidative lesions involves the increased expression of a range of pro-inflammatory cytokines (TNFα and interleukin 1β), chemokines (e.g., interleukin 8) and adhesion genes. Nitrogen oxides are also oxidative pollutants found in the atmosphere. The main source of anthropogenic emissions of nitrogen oxides is the combustion of fossil fuels from stationary sources (heating, power generation) and motor vehicles. Their presence is responsible for smog and acid rain. Under certain environmental conditions, nitric oxide is rapidly converted to nitric acid or nitrogen dioxide by atmospheric oxidants such as ozone.
A Chinese study in 2014 identified the top 5 skin problems associated with pollution. Blackheads were at the top, followed by allergies and skin sensitivity, dull skin, acne and dry skin.
What is the role of antioxidants?
The endogenous antioxidant capacity of the skin is a major element of its response to oxidative stress caused by exposure to UV or other external aggressions. However, natural antioxidant defense loses much of its effectiveness during oxidative stress.
Therefore, the use of antioxidants such as L-ascorbic acid (vitamin A), α-tocopherol (vitamin E) or tea polyphenols (Kaur et al. 2007) is a way to compensate and strengthen the skin’s endogenous protection and to prevent oxidative damage.
Because of their ability to trap free radicals and to inhibit lipid peroxidation, antioxidants have also been studied in the formulation of anti-aging care (Laguerre et al., 2007).
Protection against the harmful effects of UV overexposure:
The use of antioxidants is a good strategy to protect skin from photo-aging and the positive effect of their application has been demonstrated in clinical studies. Vitamins C and E, as well as retinoids, are the most used antioxidants by cosmetic laboratories. However, plant-derived polyphenols are recognized as good antioxidants and are therefore increasingly formulated. Polyphenols extracted from green tea (EGCG), soybeans (genistein and daidzein) and berries have indeed been recognized for their beneficial effects.
In a world where people travel a lot and where sports and outdoor activities are very popular, prolonged exposure to UV radiation is becoming more and more frequent. The application of sunscreen is essential to protect the skin but it is not sufficient. The efficacy of these protective creams is limited by the frequency of use and application by the user. Moreover, their spectrum of protection is often incomplete (Burke, 2004). Currently, sunscreens are made up of so-called “filtering” molecules that are efficient only in specific UV spectrums such as UVA or UVB. These molecules have the role of absorbing sunlight and improving the sunscreen’s protection for the entire duration of exposure to sun. However, these molecules either do not filter through the whole UV range, or they are insufficiently photostable. As a result, after a certain duration of exposure, they are degraded and free radicals are formed, which continued to cause damage after application to the skin (Damiani et al., 2006). The addition of antioxidants to the sunscreen formulation would “stabilize” the molecules and contribute to preserving the protection index, while fighting against photo-accelerated aging (Burke, 2004). Some authors have shown that the combination of photoprotective agents, or agents with multiple modes of action, may be required to optimize UV protection.
Muizzudin et al. (1999) have also shown that the application of a mixture of commercial antioxidants and free radical scavengers on human skin can prevent skin cancer and photo-accelerated aging. Other studies have also shown the importance of plant polyphenols in the fight against photoaccelerated aging (Leu et al., 2006).
Antioxidants to protect the skin from the effects of pollution
Like UV rays (A and B), pollution attacks the cells of the dermis. The free radicals constituting this poisoned duo damage the skin barrier by altering the cellular hydrolipidic film. As a result, complexion becomes duller, skin ages faster (under the effect of oxidative stress) and pigmented spots appear. Antioxidants are powerful anti-pollution ingredients that can be applied directly to the skin. They play a protective role by helping the skin renew itself and promote its defense mechanisms by stimulating the natural cellular metabolism.
New cosmetic antipollution treatments contain active antioxidants and free radicals scavenger (vitamin C, E, active agents derived from brown algae, polyphenols, etc.) capable of slowing the action of free radicals caused by pollution and strengthening the skin’s defense system, which is by itself quickly overcome when confronted to multiple attacks. They also contain sunscreens to combat harmful pollution and UV radiation. Beyond the defense process, antipollution care also contains active ingredients capable of repairing damage caused by pollution (anti-aging agent).
Why did Bio Forextra focus on antioxidants from the boreal forest?
Trees concentrate, particularly in their bark, natural antioxidant molecules that help the plant protect itself against external aggressions such as microorganisms and insects, but also pollution and UV radiation. These antioxidants are mainly from the large family of polyphenols. Trees that grow in the boreal forest are subjected to extreme northern environments: cold, dry and harsh winters alternating with very hot, humid summers with very high UV indices. Their protective skin, which is their bark, protects them and allows them to survive for tens or even hundreds of years.
A well-known example of polyphenols is trans-resveratrol, contained in red wine, but also in the bark of black spruce, a coniferous tree of the boreal forest which has the ability to survive in northernmost regions. Bio ForeXtra has developed extraction processes to target and extract this family of molecules from the recycled bark of different tree species. This process allows them to be isolated and concentrated in order to enhance their use as protective antioxidants and skin repairers.
Are they compatible with all skin types?
Yes, because all skins are affected by oxidation.
When should you start using products containing antioxidants?
There is no age! For a preventative effect, antioxidants can be used as soon as possible.
OUR ANTIOXIDIZING SUGGESTIONS
The ultimate anti-aging active from the boreal forest
The boreal source of resveratrol
Antioxidants are valuable allies to help the skin fight against free radicals, factors of premature skin aging. Using a cream that contains antioxidants is therefore contributing to the health of the skin. This is especially interesting for people who smoke and who know the effect on the quality of the skin, or those who are often exposed to the sun or in a city with a high pollution rate. Moreover, the antioxidant active ingredients of Bio Forextra guarantee an effective protection without fragilizing, and free of ingredients that could be harmful to any type of skin.
Burke KE (2004) Photodamage of the skin: protection and reversal with topical antioxidants :149-155.
Damiani E, Rosati L, Castagna R et al (2006) Changes in ultraviolet absorbance and hence in protective efficacy against lipid peroxidation of organic sunscreens after UVA irradiation. Journal of photochemistry and Photobiology B: Biology 82:204-213
Hillion K. (2003) La photo-protection antiradicalaire: intérêts et limites.
Pharmacie, Faculté de Pharmacie : Université Rennes 1 : 293
Kaur IP, Kapila M and Agrawal R (2007) Role of novel delivery systems in developing topical antioxidants as therapeutics to combat photoageing. Ageing Research Reviews 6:271-288
Laguerre M, Lecomte J and Villeneuve P (2007) Evaluation of the ability of antioxidants to counteract lipid oxidation: Existing methods, new trends and challenges. Progress in Lipid Research 46:244-282
Leu SJ, Lin YP, Lin RD et al (2006) Phenolic constituents of Malus doumeri var. formosana in the field of skin care. Biological and Pharmaceutical Bulletin 29:740-745
Lupo MP (2001) Antioxidants and vitamins in cosmetics. Clinics in Dermatology 19:467-473
Murray J.C., Burch J.A., Streilein R.D., Iannacchione M.A., Hall R.P. et Pinnell S.R. (2008) A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation
Journal of the American Academy of Dermatology 59: 418-425
Zang X., Wu R., Fu W., Xu L. et Lam P. (2004) Production of reactive oxygen species and 8-hydroxy-2’deoxyguanosine in KB cells co-exposed to benzo[a]pyrene and UV-A radiation Chemosphere, 55: 1303-1308