The Effect of Oils on the Stratum Corneum

Blog Archive | 4 minutes  | Author: Kulvinder Kaur , MChem.

Introduction to the skin barrier function

The skin (epidermis) is the largest organ in the mammalian body and its role is not to simply cover the body, but to provide a defence mechanism which protects the body from the external environment. One of the most important roles of the skin is to maintain homeostasis by preventing uncontrolled loss of vital ingredients: water, ions and serum proteins from the organism to the environment. In 1928, Marchionini and Schade introduced this concept as the skin barrier function.1

The majority of the skin barrier function resides in the outermost layer called the stratum corneum (SC). The schematic structure of the epidermal barrier is illustrated in Figure 1.2 As you can see, the SC mainly consists of cells called corneocytes which are surrounded by water insoluble molecules called lipids. This in turn creates the water barrier (also known as the permeability barrier).

The permeability barrier function is the most important role in the skin in order to maintain hydration and prevent water loss.3 It is necessary to lock in moisture as hydration affects the skins appearance, mechanical properties and cell signalling processes.4

 

Schematic structure of the epidermal barrier with its morphological and functional elements

Figure 1: Schematic structure of the epidermal barrier with its morphological and functional elements.

 

What do we mean by Transepidermal Water Loss (TEWL)?

Transepidermal Water Loss (TEWL) is the amount of water that passively evaporates through the stratum corneum to the external environment and is an indicator of the integrity of the skin barrier function. More water can escape through the stratum corneum if the strength and integrity of the skin barrier are compromised, thus resulting in an increased level of TEWL.3 This in turn, can lead to skin dryness, cracking and roughness.

There are many factors which can interfere with TEWL including: humidity and temperature changes and the products applied to the skin. Surfactants are present in most cosmetic formulations with the primary role of removing dirt and unwanted materials from the skin. However, surfactants generally bind to the proteins in the stratum corneum causing the skin barrier to weaken and allow more water to escape to the environment.5 It is for this reason that cosmetic formulators seek out ingredients that can help reduce TEWL and strengthen or maintain the skin barrier function of the stratum corneum.

 

How do oils help reduce Transepidermal Water Loss (TEWL)?

Over the years, it has become common knowledge that enhanced moisturisation can be achieved by supplementing oils with a high concentration of fatty acids into cosmetic formulations. It has been demonstrated that cleansing products are able to remove dirt and bacteria from the skin while simultaneously depositing oils to improve skin feel, reduce TEWL and improve the skin barrier function.5

Healthy skin requires a healthy skin barrier function which relies on the amount of lipids (fatty acids) present in the corneocytes.6 A reduction of the lipid content will lead to a compromised skin barrier and increased TEWL. For this reason, it is very important to select the most suitable and effective oil for your formulation. You will need to consider the fatty acid content of the oil to ensure that the product will deeply penetrate the stratum corneum and offer a long-lasting moisturising. You will also need to ensure that your formulation provides an occlusive effect on the skin – this means that the product will need to form a barrier between the skin and the environment which in turn, reduces TEWL and further enhances moisturisation.

 

The Benefits of Baobab Oil

INCI: Adansonia Digitata

The Baobab (Adansonia digitata) tree belongs to a pan-tropical family across Madagascar, north western Australia and sub-Saharan Africa. For many years the Baobab tree has been well known for its medicinal and nutritional value. Recently, there has been a growing interest in Baobab seed oil, which is extracted from its fruit pulp, for its uses and benefits to the cosmetic industry.

The seed oil is rich in oleic, linoleic and palmitic acids which make up the major fatty acids that are involved in the mechanism to reduce TEWL, thus softening the skin and restoring moisture in the epidermis.6  The fatty acid content of Baobab oil can be found in Table 1.

Komane et al. studied the efficacy of Baobab seed oil on moisturisation of the skin by measuring TEWL and hydration of the skin using a capacitance-corneometer.  The results indicated reduced TEWL and significantly improved capacitance moisture retention. Thus, we can confirm that when Baobab oil is topically applied to the skin, it has the ability to penetrate into the epidermis and restore the integrity of the skin barrier function.

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Composition of Baobab Oil

Table 1: Composition of Baobab oil. 

 

The Benefits of Moringa Oil

INCI: Moringa Oleifera

Moringa Oleifera is another pan-tropical species that can be found in the western and sub-Himalayan tracts. Similar to Baobab oil, Moringa seed oil is also rich in oleic acid which is integral in protecting the skin barrier and nourishing the skin. What makes Moringa oil so unique is that it is rich in cytokinins, most importantly Zeatin, which helps promote cellular growth and delays the aging process.

As well as being rich in powerful antioxidants, Moringa oil contains many essential ingredients such as Vitamin A, Vitamin C and phenolic compounds. As a result, Moringa oil can be used to protect the skin of oxidative stress and reduce skin sebum secretion (oily skin), both of which are often associated with acne and psoriasis.7

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Composition of Moringa Oil

Table 2: Composition of Baobab oil. 

 

Sigma Oil Seeds

After reading the above information, you may be wondering where to find such exotic oils. Lawrence Industries are proud to announce that we have partnered with Sigma Oil Seeds to supply you with these natural and organic products.

Sigma Oil Seeds import the seeds from Africa and press them in The Netherlands to ensure the best quality oils are produced to European standards. To find out more about other oils we can offer from Sigma Oil Seeds, please read our previous blog article.

For samples or any further information about this article and our oils, please get in touch a member of the technical team!

 

References:

1. Schade, T. and A. Marchionini (1928) Physical chemistry of the skin surface. Arch. Dermatol. Syph. 193: 73–81.

2. Darlenski, R., Kazandjieva, J., Tsankov, N., (2011). Skin barrier function: Morphological basis and regulatory mechanisms. https://www.researchgate.net/publication/285876351_Skin_barrier_function_Morphological_basis_and_regulatory_mechanisms

3. Oh, M. J., Cho, Y. H., Cha, S. Y., Lee, E. O., Kim, J. W., Kim, S. K., & Park, C. S. (2017). Novel phytoceramides containing fatty acids of diverse chain lengths are better than a single C18-ceramide N-stearoyl phytosphingosine to improve the physiological properties of human stratum corneum. Clinical, cosmetic and investigational dermatology10, 363–371. https://doi.org/10.2147/CCID.S143591

4. Handbook of Cosmetic Science and Technology, 3rd edition, edited by O. Barel, A., Paye, M., Maibach, H. I.,

5. Kilpatrick-Liverman, L., Mattai, J., Tinsley, R., and Wu, J., Colgate-Palmolive Technology Center, Mechanisms of Skin Hydration, Handbook of Cosmetic Science and Technology.

6. Komane, B. M., Vermaak, I., Kamatoua, G. P. P., Summers, B., Viljoena, A. M., (2017). Beauty in Baobab: a pilot study of the safety and efficacy of Adansonia digitata seed oil. Revista Brasileira de Farmacognosia, 27(1), 1-8. https://doi.org/10.1016/j.bjp.2016.07.001

7. Ali, A., Naveed, A., Khan, H. M. S., Ullah, A. et a, (2012) .Effect of Moringa oleifera on undesireble skin sebum secretions of sebaceous glands observed during winter season in humans. Biomedical Research, 24, 127-130

Author: Kulvinder Kaur , MChem.

Kulvinder studied Chemistry at the University of Leicester, where she obtained a first class degree. She looks after all of the industry sections across England and Wales.