The benefits and challenges of treating skin with natural oils.

The term natural oil refers to a fixed (non-volatile) oil of animal or plant origin. These types of oils - in contrast to essential (volatile) oils, which are obtained by steam distillation methods of plant matter - are typically obtained from plant seeds and nuts by a mechanical pressing technique or solvent extraction. The natural movement in cosmetics of the 21st century has led to renewed interest in formulating skin care products with botanical ingredients. In this article, we discuss the benefits and caveats of natural oil treatments as moisturizing agents (as occlusives and emollients) as well as their utility in wound healing and treatment of skin diseases. We also address the paradoxical behaviour of natural oils in relation to barrier function and highlight the current state of our knowledge with respect to the use of natural oils in neonatal skin care. Finally, we provide a comparison of natural oils to conventional petroleum-based oils.

Le terme huile naturelle fait référence à une huile fixe (non volatile) d'origine animale ou végétale. Ces types d'huiles, contrairement aux huiles essentielles (volatiles) qui sont obtenues par des méthodes de distillation à la vapeur de matières végétales, sont généralement obtenues à partir de graines et de noix de plantes par une technique de pressage mécanique ou d'extraction par solvant. Le mouvement naturel des cosmétiques du XXI siècle a suscité un regain d'intérêt pour la formulation de produits de soins pour la peau à base d'ingrédients botaniques. Dans cet article, nous examinons les avantages et les mises en garde des traitements à base d'huiles naturelles en tant qu'agents hydratants (comme occlusifs et émollients), ainsi que leur utilité dans la cicatrisation des plaies et le traitement des maladies de la peau. Nous abordons également le comportement paradoxal des huiles naturelles par rapport à la fonction barrière et mettons en évidence l'état actuel de nos connaissances en ce qui concerne l'utilisation des huiles naturelles dans les soins de la peau néonatale. Enfin, nous comparons les huiles naturelles aux huiles conventionnelles à base de pétrole.

Facial skin ageing: Key concepts and overview of processes.

INTRODUCTION: The face is a cosmetically sensitive region where the process of ageing is most clearly manifested. With increased focus on anti-ageing and longevity, more anti-senescent treatments are being proposed despite limited evidence. This study outlines the pathways and mechanisms underpinning the biological process of ageing in the face. METHODS: Comprehensive searches of MEDLINE, EMBASE, Cochrane Library and CINAHL from inception to 2020. Inclusion criteria included all empirical human research studies specific to facial ageing features, written in the English language. RESULTS: A total of 65 papers met inclusion criteria for analysis. Pathways were subdivided into intrinsic and extrinsic senescence mechanisms. Intrinsic pathways included genetics, generation of reactive oxygen species and hormonal changes. Extrinsic pathways included photoageing and damage to skin layers. The combined intrinsic and extrinsic pathway alterations result in wrinkles, higher laxity, slackness and thinning of the skin. Skin functions such as barrier immune function, wound healing, thermoregulation and sensory function are also impaired. CONCLUSION: The ageing process is unique to the individual and depends on the interplay between an individual's genetics and external environmental factors. Through understanding the molecular and cellular mechanisms, an appreciation of the consequent structural and functional changes can be achieved. Based on this knowledge, further research can focus on how to slow or impede the ageing process and identify specific targets to develop and evolve new treatment strategies.

INTRODUCTION: Le visage est une zone du corps esthétiquement importante où le processus de vieillissement se manifeste particulièrement clairement. Avec l'attention croissante portée aux soins anti-âge et à la longévité, de plus en plus de traitements anti-sénescent sont proposés malgré des preuves d'efficacité limitées. Cette étude décrit les voies métaboliques et les mécanismes à la base du processus biologique de vieillissement du visage. MÉTHODES: Recherches exhaustives dans les bases de données bibliographiques MEDLINE, EMBASE, Cochrane Library et CINAHL de leur création à 2020. Les critères d'inclusion comprenaient toutes les études empiriques spécifiques aux caractéristiques du vieillissement du visage chez l'Homme, rédigées en langue anglaise. RÉSULTATS: Un total de 65 articles répondait aux critères d'inclusion pour l'analyse. Les voies métaboliques ont été subdivisées en mécanismes de sénescence intrinsèques et extrinsèques. Les voies intrinsèques comprennent la génétique, la génération de dérivés réactifs de l'oxygène et les changements hormonaux. Les voies extrinsèques comprenaient le photovieillissement et les dommages causés aux couches de la peau. Les altérations combinées des voies intrinsèque et extrinsèque entraînent des rides, une laxité plus importante, un relâchement et un amincissement de la peau. Les fonctions cutanées telles que la fonction de barrière immunitaire, la cicatrisation, la thermorégulation et la fonction sensorielle sont également altérées. CONCLUSION: Le processus de vieillissement est unique à l'individu et dépend de l'interaction entre la génétique d'un individu et les facteurs environnementaux externes. La compréhension des mécanismes moléculaires et cellulaires permet d'appréhender les changements structurels et fonctionnels qui en découlent. Sur la base de ces connaissances, la recherche peut se concentrer sur les moyens de ralentir ou d'entraver le processus de vieillissement et identifier des cibles spécifiques pour élaborer et développer de nouvelles stratégies de traitement.

Role of pH in skin cleansing.

BACKGROUND: The importance of maintaining the acid-mantle of human stratum corneum to maintain its healthy barrier and skin's biological functions such as desquamation and lipid biosynthesis is well recognized in the literature. An outcome of this has been an increase in the number of skincare products formulated at or near the skin pH with an implication that a product formulated at skin pH will be good for skin. Such an assumption often does not take into account the specific interactions of ingredients in the product with the stratum corneum under skin pH conditions. OBJECTIVE: The objective of this research was to determine whether a skin cleansing product by virtue of its pH being same as "skin pH" is milder to skin. METHODS: A well established Forearm Controlled Application Test (FCAT) protocol was used in clinical studies to compare "skin pH" cleansing systems with neutral pH cleansing systems. Specifically, certain commercially available "skin pH" cleansing bars were compared with a neutral pH syndet bar in two separate FCAT studies. Since these bars differed in their surfactant composition, in a separate FCAT study, two identical prototype bar formulations differed only in their pH were compared. Additionally, two body wash liquid prototypes, identical in composition but differing only in their pH were also compared in another FCAT study. RESULTS: The results obtained showed that skin-cleansing systems formulated solely or predominantly with anionic surfactants under skin pH conditions can result in increased skin dryness and irritation compared to those under neutral pH conditions. The results are explained in terms of the increased electrostatic interaction of anionic surfactants with stratum corneum under low pH conditions compared to neutral pH conditions. CONCLUSION: Skin-cleansing systems formulated solely or predominantly with anionic surfactants under skin pH conditions can result in increased skin dryness and irritation compared to those under neutral pH conditions. Any skin cleansing product by virtue of its pH being same as that of "skin pH" does not guarantee that it will be good for skin. The mildness of a cleanser will be determined by the interactions of its surfactants and other ingredients with stratum corneum under its formulated pH conditions.

CONTEXTE: l'importance de la protection du manteau acide de la couche cornée humaine en vue de maintenir une barrière saine et les fonctions biologiques de la peau, telles que la desquamation et la biosynthèse lipidique, est bien reconnue dans la littérature médicale. Cela a eu pour résultat l'augmentation du nombre de produits cosmétiques formulés à un pH proche ou identique au pH de la peau, impliquant ainsi qu'un produit formulé au pH de la peau sera bon pour la peau. Cette hypothèse ne tient souvent pas compte des interactions spécifiques des ingrédients du produit avec la couche cornée dans des conditions de pH de la peau. OBJECTIF: l'objectif de cette recherche était de déterminer si un nettoyant pour la peau formulé à un pH identique au « pH de la peau ¼ est, pour cette raison, plus doux pour la peau. MÉTHODES: un protocole bien établi de test d'application contrôlée sur l'avant-bras (Forearm Controlled Application Test, FCAT) a été utilisé dans des études cliniques pour comparer les nettoyants à « pH de la peau ¼ et les nettoyants à pH neutre. Plus précisément, certains savons à « pH de la peau ¼ disponibles dans le commerce ont été comparés à un savon surgras à pH neutre dans deux études distinctes faisant appel au FCAT. La composition en termes d'agents de surface de ces savons étant différente, une étude distincte faisant appel au FCAT a comparé deux prototypes de savons de composition identique mais de pH différent. De plus, deux prototypes de savon liquide pour le corps, de composition identique mais de pH différent, ont également été comparés dans une autre étude faisant appel au FCAT. RÉSULTATS: les résultats obtenus ont montré que les nettoyants pour la peau formulés uniquement ou principalement avec des agents de surface anioniques dans des conditions de pH de la peau peuvent entraîner une augmentation de la sécheresse et de l'irritation cutanées, par rapport à ceux formulés dans des conditions de pH neutre. Les résultats s'expliquent par l'interaction électrostatique accrue des agents de surface anioniques avec la couche cornée dans des conditions de pH faible par rapport aux conditions de pH neutre. CONCLUSION: les nettoyants pour la peau formulés uniquement ou principalement avec des agents de surface anioniques dans des conditions de pH de la peau peuvent entraîner une augmentation de la sécheresse et de l'irritation cutanées, par rapport à ceux formulés dans des conditions de pH neutre. La formulation d'un nettoyant pour la peau à un pH identique au « pH de la peau ¼ ne garantit pas qu'il sera bon pour la peau. La douceur d'un nettoyant sera déterminée par les interactions de ses agents de surface et de ses autres ingrédients avec la couche cornée dans ses conditions de formulation en termes de pH.

Modified Corneosurfametry as a new accelerated high-throughput ex vivo methodology for predicting cleanser effects towards human skin.

BACKGROUND: Corneosurfametry (CSM) was originally developed as a tool to predict irritation potential of cleansers. In this method, surface skin stripped using cyanoacrylate is contacted with surfactants/products, rinsed and stained with toluidine blue and basic fuschin dyes. The intensity of staining increases with increases in irritation potential of surfactant. Our objective was to modify the CSM technique to achieve better control of the tape stripping process. Another objective was to correlate the modified CSM (MCSM) with a traditional in-vivo forearm controlled application test (FCAT) for mildness and to explore its utility to assess the state of corneum after a clinical test. METHODS: Surface skin cells were tape stripped from forearms of volunteers with D-Squame Adhesive Discs. Discs were treated with a 10% solution of the product in a 96-plate well for 10 min, rinsed, dried and treated with basic fuschin-toluidine blue dye solution, rinsed and dried again. Forearm Controlled Application Test (FCAT) was based on a published protocol. Tape strips obtained after product treatment were also analyzed by the MCSM procedure without additional product treatment. RESULTS: Mildness/barrier damage assessed from in-vivo FCAT showed a similar ranking to the MCSM results. MCSM, TEWL and Erythema analysis of between-treatment differences showed a good correlation indicating that barrier damage seen in in-vivo studies can be predicted from ex-vivo MCSM studies. MCSM analysis of tape strips after the FCAT study showed that the damage decreased with increase in tape strip number. A moisturizing body wash (MBW) with mild surfactants showed the least damage in all layers. In contrast, harsh dish washing liquid showed significantly higher damage down to several layers. Another MBW with petrolatum in a harsher base showed damage almost similar to that of the harsh dish washing liquid in the surface layers. Thus, the MCSM was able to show underlying damage which would have been normally masked by the deposited petrolatum. CONCLUSION: The MCSM assay was shown to be a valuable tool for accelerated high throughput evaluation of mildness of surfactants and fully formulated products. MCSM can also be used to assess the state of the corneum after a product treatment.

Randomized, double-blinded, vehicle-controlled, split-face study to evaluate the effects of topical application of a Gold Silk Sericin/Niacinamide/Signaline complex on biophysical parameters related to skin ageing.

OBJECTIVE: To investigate the effects of topical application of a Gold Silk Sericin (GSS) complex on biophysical parameters related to skin ageing. METHODS: A range of non-invasive bioengineering methods were deployed in an 8-week randomized, double-blinded, vehicle-controlled, split-face study among 40 female subjects aged 40-70. Endpoints measured included expert grades of skin condition, stratum corneum (SC) hydration, SC barrier function, elasticity and surface topography. RESULTS: The GSS complex produced significant single-variable (P < 0.05) improvements in SC hydration, barrier function, elasticity and surface topography compared with the Vehicle control. CONCLUSION: The GSS complex examined in this study represents an interesting new cosmetic topical technology with which to address multiple aspects of aged/photoaged female facial skin.

Effect of mixed surfactants on stratum corneum: a drying stress and Raman spectroscopy study.

OBJECTIVE: Stratum corneum (SC) lipids are known to play an important role in barrier properties of skin by maintaining the optimal hydration levels. The disruption of SC lipids by cleanser surfactants is believed to lead to dry skin damage which can be a precursor to other skin disorders. The purpose of this study is to investigate the effects of commonly used anionic and zwitterionic surfactants sodium lauryl ether sulphate (SLES) and cocoamidopropyl betaine (CAPB) on the generation of drying stresses in SC and the role played by lipids. METHODS: Stratum corneum separated from pig skin was treated with various surfactants (SDS, SLES and CAPB) their mixtures and solvents. The tensile response to these treatments was measured by using a dynamic mechanical thermal analyzer. A Raman spectroscopy study of the treated samples was performed to investigate the effects of lipid modification (lipid chain conformational order and lipid removal) on stress generation in SC. RESULTS: The effects of commonly used anionic and zwitterionic surfactants on the generation of drying stresses in SC were studied. Although known to be milder in comparison with SDS, both SLES and CAPB generated high drying stresses individually. In mixtures, SLES-CAPB at 4 : 1 ratio leads to lower drying stress as compared to water alone. A Raman spectroscopic study of surfactant-treated SC shows changes in lipid chain conformational order as well as a decrease in lipid-protein ratio in SC. A chloroform-methanol 2 : 1 treatment leads to the highest drying stress as well delipidization of SC. CONCLUSION: The results show a correlation between generation of drying stress in SC and extent of lipid modification. We propose that the changes in lipid conformational order and removal of lipid components affect the stress relaxation properties of SC leading to high drying stresses.

Characteristic differences in barrier and hygroscopic properties between normal and cosmetic dry skin. II. Depth profile of natural moisturizing factor and cohesivity.

OBJECTIVE: In a previous paper (Lu et al., International Journal of Cosmetic Science, in press), we reported that in comparison with normal skin, cosmetic dry skin characteristically has a thicker stratum corneum (SC) with weaker barrier quality. Our goal here was to obtain a more complete picture of the difference between normal and cosmetic dry skin, by further analysing the data collected from the same clinical study to address two additional aspects of skin: the amount and depth profile of natural moisturizing factor (NMF) and the cohesivity of the SC. METHOD: The SC samples were collected by sequential tape stripping in a clinical study consisting of 64 healthy Caucasian female subjects with either normal or cosmetic dry skin. Protein and free amino acids (FAA) on tape strips were extracted and analysed using high-throughput methods. The level of pyrrolidone carboxylic acid (PCA), the prominent component of NMF, was detected using HPLC analysis. RESULTS: It was found that dry skin had significantly lower ratios of FAA/protein and PCA/protein across the stripped SC depth, corresponding to a lower hydration level compared with the normal skin. Our results indicated that filaggrin to FAA hydrolysis occurred deeper in dry skin and at a lower level compared with normal skin. In addition, the mass of proteins stripped from dry skin subjects was significantly higher than that from the normal skin counterpart, especially for the first 10-12 tape strips. CONCLUSION: Our results showed that, compared with normal skin, cosmetic dry skin had a lower NMF level across the SC depth and a lower cohesivity. Such results suggested that NMF levels are critical for cosmetic skin conditions, and lower NMF production may be associated with dry skin. In addition, the NMF level and its depth profile and the SC cohesivity are useful clinical end points for assessing the efficacy of dry skin treatments such as skin moisturizers.

Effects of tocotrienol on aging skin: A systematic review.

The skin is the largest organ of the body that protects from mechanical, thermal, and physical injury. However, the function and appearance of skin visibly degenerates with age due to its frequent exposure to harmful effects of the environment, including ultraviolet irradiation and hazardous substances, in addition to the progression of oxidative stress in aging. These factors result in phenotypic changes in the skin, including wrinkling, pigmentation, reduced elasticity, and hydration during aging. Many natural antioxidant compounds have been studied extensively to reverse the signs of aging skin. Tocotrienols are a subfamily of vitamin E with potent antioxidant activity. Therefore, supplementation with vitamin E in the form of tocotrienol may efficiently protect skin from aging. In this review, the effects of tocotrienol on skin health, including pigmentation, moisture, and wrinkles during aging and UV exposure, were systematically evaluated based on a literature search of the PubMed and Scopus databases. The present data showed that tocotrienols protect the skin from inflammation, UV radiation and melanin accumulation. As the therapeutic value of tocotrienols grows, the potential of these vitamin E analogs to the skin requires further investigation.