Resveratrol as an active ingredient for cosmetic and dermatological applications: a review.

Resveratrol is now being increasingly used in cosmetology and dermatology. This polyphenolic phytoalexin present in large amounts in red grapes and berries has a number of scientifically proven health-promoting properties associated with a positive effect on the cardiovascular system, lowering the concentration of low-density lipoprotein, and the ability to inhibit the cyclooxygenases activity. Additionally, it has antiproliferative, anti-angiogenic, anti-inflammatory, antioxidant, and antimicrobial properties. Its popularity in cosmetology and dermatology is primarily associated with proven ability to penetrate the skin barrier and antiaging activity. It has been shown that formulations with resveratrol can stimulate the proliferation of fibroblasts and contributing to the increase in the concentration of collagen III. Resveratrol has an affinity for the estrogen protein receptors (both ERα and ERß), thereby contributing to the stimulation of collagen types I and II production. Moreover, resveratrol also has the antioxidant properties, thus can protect cells against oxidative damage associated with the effects of free radicals and UV radiation on the skin by reducing the expression of AP-1 and NF-kB factors and it slows down the process of photoaging of the skin. This study reviews literature on the skin care properties of resveratrol and its dermal bioavailability, metabolism, and dermal safety of application.

Preliminary study of guard hair morphology in four dog breeds.

BACKGROUND: Morphological differences between mammalian hair types are useful for species distinction. Differences in animal hair structure are observed between species, whereas there may be breed differences within a species. HYPOTHESIS: Guard hair structure may vary between different dog breeds. ANIMALS: Hair samples were collected from 73 dogs of four breed types (wire-haired Dachshund, Labrador retriever, German shepherd dog and Yorkshire terrier). METHODS: Hair was measured and analysed by scanning electron microscopy. The following were evaluated: hair thickness; medulla to hair cross-sectional area ratio; scale density, pattern and margins; and medulla shape, composition and structure. RESULTS: There were significant differences in all measured parameters between breeds. CONCLUSIONS AND CLINICAL IMPORTANCE: These study findings may be useful for the study of classifying dog breeds and for forensic identification of a dog breed through hair sampling.

In vivo and ex vivo evaluation of cosmetic properties of seedcakes.

The seedcakes are a potential source of natural bioactive substances: antioxidants, protein, and carbohydrates. Thus, they may scavenge free radicals and have an effect on the stratum corneum hydration and epidermal barrier function. The aim of the study was to evaluate the in vivo and ex vivo properties of emulsions with the seedcake extracts using the pH meter, corneometer, tewameter, methyl nicotinate model of micro-inflammation in human skin, and tape stripping of the stratum corneum. The in vivo and ex vivo studies showed that the emulsions with Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts have anti-inflammatory and antioxidant activity. The 6-week topical application of the emulsions with the B. officinalis and N. sativa seedcakes significantly reduced skin irritation and influenced the improvement of the skin hydration and epidermal barrier function compared with placebo. The seedcakes due to their antioxidant and anti-inflammatory activities have potential application in anti-aging, moisturizing, mitigating, and protective cosmetics.

Influence of polyphenols on the physiological processes in the skin.

In the last decade antioxidants from a group of polyphenols have been proposed as one of the most effective functional ingredients of anti-ageing properties that counteract the effects of oxidative damage to the skin. It has been shown that the use of polyphenols affects skin protection and mitigates inflammatory conditions of the skin. Numerous studies have confirmed that polyphenols by neutralizing free radicals, antioxidant activity and by their ability to chelate ions of transition metals can effectively reduce the level of nonprotein inflammatory mediators. The biological activity of polyphenols in the skin is primarily determined by their physicochemical properties and the ability to overcome the epidermal barrier as they try to reach appropriate receptors. This study reviews literature on the effects of polyphenols relating to the physiological processes in the skin and role of the major plant polyphenols in cosmetology and dermatology.

The influence of surfactants and hydrolyzed proteins on keratinocytes viability and elasticity.

BACKGROUND/PURPOSE: The knowledge how surfactants and hydrolyzed proteins influence the elastic properties of living epidermal keratinocytes is sparse. We demonstrate that the stiffness of cells measured by atomic force microscope (AFM) can be correlated with viability test. METHODS AND MATERIALS: The effects of sodium lauryl sulphate (SLS) and hydrolyzed collagen (HK) of molecular weight 9 kDa were examined with respect to human keratinocytes viability and elasticity. MTT assay was applied to determine the survival fraction of keratinocytes treated with SLS and HK solutions of various molar ratios. The AFM measurements of the keratinocytes stiffness were carried out immediately after the exposure of cells to the SLS and HK, respectively. RESULTS: The increase of the SLS concentration resulted in the decrease of cells proliferation and this effect was inhibited by addition of HK. The strongest inhibition was observed for the SLS:HK molar ratio equals to 2:1. AFM study shows decrease in the cell stiffness for cells treated with SLS. Fluorescence microscopy reveals remodeling of actin filaments of SLS-treated cells. SLS:HK mixture treatment results in mechanical stiffness close to untreated cells. CONCLUSION: These results provide possible correlations between mechanical properties and viability of keratinocytes when the chemical stress occurs.

Liquid-crystalline membrane permeation ability for selected nitro hair dyes.

AIM: A comparison of permeation ability of selected semi-permanent hair dyes and an attempt to estimate the influence of fundamental physicochemical parameters on dyes' epidermal penetration rate. METHODS: Dyes' permeation ability through liposome membrane (as a model of stratum corneum) with side-by-side cells was assessed. RESULTS: It has been shown that the chosen dyes are capable of permeating the membrane. High penetration coefficients (Kp) were obtained for a simple nitrophenylenediamines and nitroaminophenols. Their N-, O-hydroxyalkyl substitution significantly limits penetration. H-bonding capability has a major impact on the investigated dyes' permeation ability. Substituents with H-bonding properties can significantly limit dyes' penetration, even in the case of lipophilic structures. Special attention should be placed into compounds with strong intramolecular H-bonding properties, which improve transmembrane transport. CONCLUSION: Substitution patterns have an influence on selected nitro dyes' permeation through a model stratum corneum. Permeation is limited by dyes diffusive properties (mostly by its H-bonding properties). Hydroxyalkylation results in hindered dyes permeation: purple, violet and blue nitrophenylenediamine or nitroaminophenol derivatives are less permeable than its not substituted analogues.

Methods for evaluation of cosmetic antioxidant capacity.

The skin as the largest part of human body is one of the main targets for ultraviolet radiation, environmental pollution, toxic chemicals and some metal ions, which share responsibility for the formation of free radicals. The resulting free radicals, both oxygen and nitrogen species are one of the main causes of aging due to impaired regulation of cell respiratory metabolism involving incomplete oxygen reduction in mitochondria and production a superoxide anion, hydroxyl radicals et al. In modern cosmetology to minimize the adverse effects of free radicals, antioxidants, which inhibit free radical reactions, mainly autoxidation processes are used. Currently, not only many cosmetic products containing antioxidants are available, but a large diversity of methods for determination of cosmetics antioxidant activity is also accessible. These methods can be divided into three main groups: in vitro, in vivo, and ex vivo as reported herein. Due to lack of standardization and validation it is necessary to use a variety of methods as well as conditions for those purposes, which are presented to the context.

Flavonoids as components of biologically active cosmeceuticals.

Flavonoids are multi-active components used in common cosmetics primarily for antioxidant and soothing actions. Despite this, their multi-active properties are far from being fully used. It is well known that many flavonoids provide protection from telangiectasias and petechias caused by ruptured blood vessels. Thus, the notion of a "strengthening" effect of these compounds on blood vessel walls is common. The activity of flavonoids on skin blood vessels is complex. Three main components of their activity can be distinguished: blood vessel protection, platelet aggregation prevention, and capillary permeability decrease. Each of these components is realized with the participation of several mechanisms differing on the types of receptors that the flavonoids affect. Some of them consist of a direct action on the enzymes responsible for the synthesis of substances of tissue hormone character, such as thromboxanes, histamine, or platelet activating factor. The mechanisms based on less or more indirect activity can also be met. At least 11 points for activity can be distinguished among flavonoids' actions on blood vessels.