Skin hydration effects,physico‐chemical properties and vitamin E release ratio of vital moisture creams containing water‐soluble chitosans

Synopsis The effects of the addition of water‐soluble chitosans on skin hydration, physico‐chemical properties and vitamin E release ratio of vital moisture creams (vitamin E‐containing creams) were studied. Results show that vitamin E‐containing creams containing different molecular weights and/or concentrations of water‐soluble chitosans are pseudoplastic fluids. The apparent viscosity of vitamin E‐containing creams increased with increasing molecular weight and/or with increasing concentration of water‐soluble chitosans used in the formula. The apparent viscosities of those vitamin E‐containing creams containing 0.5% water‐soluble chitosan were higher than those containing 2% glycerol monostearate (control). The higher apparent viscosity of vitamin E‐containing creams obtained using water‐soluble chitosans improves the stability and enhances skin hydration of the creams thus prepared. Such creams containing water‐soluble chitosans were stable for more than 3 months during high temperature or cyclic temperature storage, whereas those containing glycerol monostearate had a shorter storage life of 2 months. Skin hydration in terms of water‐holding capacity of vitamin E‐containing creams containing 1.0% water‐soluble chitosan was superior to those containing 2% glycerol monostearate. No erythema occurred on shaved rabbit skin after applying vitamin E‐containing creams containing water‐soluble chitosans, and the vitamin E release ratios of these creams were similar to the cream containing 2% glycerol monostearate. Résumé Nous avons étudié le rôle de l’addition de chitosanes hydrosolubles dans une crème hydratante vitale, sur le taux de relargage de vitamine E, l’hydratation de la peau et les propriétés physiscochimiques de cette préparation. Les résultats montrent que les crêmes hydratantes vitales contenant différentes masses moléculaires et/ou concentrations de chitosanes hydrosolubles sont des fluides pseudo‐plastiques. La viscosité apparente des crêmes hydratantes vitales croit avec la masse moléculaire et/ou la concentration des chitosanes employés dans la formulation. La viscosité apparente de ces crèmes hydratantes vitales contenant 0.5% de chitosane hydrosoluble est supérieure à celle contenant 2% de monostéarate de glycérol (contrôle). La viscosité apparente plus élevée des crêmes hydratantes vitales obtenue grâce à la présence de chitosane hydrosoluble améliore la stabilité, accroit l’hydratation de la peau. Les crêmes hydratantes vitales contenant du chitosane hydrosoluble sont stables pendant 3 mois au cours d’un stockage à température élevée, en continu ou cyclique. Ceux contenant du monostéarate de glycérol ont une durée de conservation inférieure, de 2 mois. L’hydratation de la peau, en terme de capacité de rétention d’eau, pour les crêmes hydrantes vitales contenant 1% de chitosane hydrosoluble sont supérieures à celles contenant 2% de monostéarate de glycérol. Aucun érythème n’apparait sur une peau de lapin rasé après application de crême hydratante vitale contenant des chitosane hydrosolubles. Le taux de relargage de vitamine E des crêmes hydratantes vitales contenant des chitosanes hydrosolubles est semblable à celui des crêmes contenant 2% de monostéarate de glycérol.     

Location‐related differences in structure and function of the stratum corneum with special emphasis on those of the facial skin

Between the two different kinds of the skin covering the body, the glabrous skin is found only on the palmo‐plantar surface because of its rather simple function to protect the underlying living tissue with its remarkably thick stratum corneum (SC) from strong external force and friction. Thus, its barrier function is extremely poor. In contrast, the hair‐bearing skin covers almost all over the body surface regardless of the presence of long hair or vellus hair. In regard to its SC, many dermatologists and skin scientists think that it is too thin to show any site‐specific differences, because the SC is just present as an efficient barrier membrane to protect our body from desiccation as well as against the invasion by external injurious agents. However, there are remarkable regional differences not only in the living skin tissue but also even in such thin SC reflecting the function of each anatomical location. These differences in the SC have been mostly disclosed with the advent of non‐invasive biophysical instruments, particularly the one that enables us to measure transepidermal water loss (TEWL), the parameter of the SC barrier function, and the one that evaluates the hydration state of the skin surface, the parameter of the water‐holding capacity of the SC that brings about softness and smoothness to the skin surface. These in vivo instrumental measurements of the SC have disclosed the presence of remarkable differences in the functional properties of the SC particularly between the face and other portions of the body. The SC of the facial skin is thinner, being composed of smaller layers of corneocytes than that of the trunk and limbs. It shows unique functional characteristics to provide hydrated skin surface but relatively poor barrier function, which is similar to that observed in retinoid‐treated skin or to that of fresh scar or keloidal scars. Moreover, there even exist unexpected, site‐dependent differences in the SC of the facial skin such as the forehead, eyelid, cheek, nose and perioral regions, although each location occupies only a small area. Between these locations, the cheek shows the lowest TEWL in contrast to the perioral region that reveals the highest one. Moreover, these features are not static but change with age particularly between children and adults and maybe also between genders. Among various facial locations, the eyelid skin is distinct from others because its SC is associated with poor skin surface lipids and a thin SC cell layer composed of large corneocytes that brings about high surface hydration state but poor barrier function, whereas the vermillion borders of the lips that are covered by an exposed part of the oral mucosa exhibit remarkably poor barrier function and low hydration state. Future studies aiming at the establishment of the functional mapping in each facial region and in other body regions will shed light on more delicate site‐dependent differences, which will provide us important information in planning the strategy to start so called tailor‐made skin care for each location of the body.     

Facial skin mapping: from single point bio‐instrumental evaluation to continuous visualization of skin hydration,barrier function,skin surface pH,and sebum in different ethnic skin types

Dry skin is one of the most important concerns of consumers worldwide. Despite huge efforts over several decades, the personal care industry still does not offer a perfect solution to satisfy the unmet needs of consumers for moisturising treatments in different ethnic groups. The paucity of data for the underlying cellular and biochemical problems in, and the effects of moisturisers on photodamaged facial skin may partly explain this. Mainly, single point measurements are used to understand the effects of products on skin physiology even on surrogate skin sites such as the non‐photodamaged volar forearm. Some groups have developed discontinuous facial maps of skin biophysical properties, however, in 2014 a continuous facial analysis of bio‐instrumental evaluations was developed using a heat map approach. These maps enabled a continuous visualization of features that not only revealed an unexpected complexity of facial skin but also indicated that use of surrogate skin sites for facial skin is inappropriate. We have demonstrated that remarkable gradients of skin hydration, TEWL, skin surface pH and sebum exist within short distances across the face and the gradients are distinctive among different ethnic groups. In addition, these studies have demonstrated that darkly‐pigmented individuals do not necessarily have a better skin barrier function than their less‐pigmented counterparts and that Caucasians have a lower facial skin surface pH compared with more pigmented subjects. Overall, there are no correlations between capacitance, TEWL and skin surface pH including individual topology angle values. Novel 3D camera approaches have also been used to facilitate a more precise assignment of measurement sites and visualisation. The 3D facial colour mappings illustrated precisely the local moisturising effects of a moisturising cream. There were subtle ethnic differences in efficacy that may be related to underlying skin biochemistry and/or ethnic differences in product application. A placebo‐controlled study using conductance measurements in Chinese subjects is also reported. Finally, a new whole face statistical approach has been taken to prove differences in skin parameters but also of moisturiser treatment that adds further to our understanding of the ethnic differences in skin physiology and product application. This paper reviews the background of the development and application of this methodology.     

Evaluation of physico‐chemical properties,trace metal content and antioxidant activity of Indian honeys

In this study, effect of plant sources viz. Gossypium hirsutum, Coriander sativum, Murraya koenigii and Dalbergia sisso on twelve physico‐chemical properties, phenolic content, flavonoids content as well as on trace mineral (Fe, Cu, Ni, Mn, Cd and Pb) contents of honey were investigated and compared. All the physico‐chemical values were in the range of approved limits of European Commission Regulation and the source of honey had a significant (P < 0.05) effect on physico‐chemical properties, phenol content, flavonoid content and trace mineral content. The results of positive correlations between physico‐chemical properties (colour and antioxidant properties) and compositional components (phenols and flavonoids content) established that antioxidant properties were dependent on source of honey rather than on colour of honey. Pattern recognition methods such as principal component analysis and linear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties, phenolic content, flavonoids content and trace metal content. The variables proline and lead exhibited higher discrimination power.     

Development and validation of a SYBR‐Green I Real‐Time PCR test to detect bivalves including Mytilus species in foods

The incidence of allergy to seafood, and in particular to molluscs is second only to that of nuts. To protect consumers, the regulators of food products insisted on identifying molluscs as allergens. The aim was to develop quantitative assay for the presence Mytilus species in processed food products. The chosen platform was real‐time PCR (qPCR) targeting either the gene encoding mitochondrial cytochrome C oxidase I or the nuclear gene encoding β‐actin. Recombinant plasmids containing each of target regions were used as a reference for quantification purposes. Limit of detection (LOD) and of quantification (LOQ) were determined. Spiked food samples containing 50–500 μg g^?1 of Mytilus chilensis were analysed both by qPCR and by ELISA. The former assay gave a positive outcome over this range, whereas the latter was sensitive down to a concentration of 125 μg g^?1.     

Angiotensin‐converting enzyme‐inhibitory and antithrombotic activities of soluble peptide extracts from buffalo and cow milk Cheddar cheeses

The aim of the study was to evaluate potential role of a water‐soluble peptide (WSP) extracts derived from buffalo and cow milk Cheddar cheeses with special reference to their antihypertension and antithrombotic activities. The WSP fractions collected at different stages of ripening were tested to assess their degree of proteolysis, their peptides were profiled by RP‐HPLC and in vitro assays for potential bioactivity were conducted. The peptide peak development was observed with slight differences in peaks number, area and height. Both angiotensin‐converting enzyme‐inhibitory and antithrombotic activities increased progressively during ripening. In comparison, the highest activities were observed in peptide extracts obtained from buffalo milk Cheddar cheese, in a dose‐dependent fashion.