Abstract: A promising strategy for maintaining a healthy and youthful phenotype during aging is that of mild stress-induced beneficial hormesis. The basis of hormesis lies in the molecular pathways of stress response, which are essential for the survival of a biological system by activation of maintenance and repair mechanisms in response to stress. Moderate physical exercise is the best example of a hormetin that brings about a wide range of health beneficial hormesis by first challenging the system. Similarly, other natural and synthetic hormetins can be incorporated in cosmeceutical formulations, and can help achieve benefits including maintenance of the skin structure and function. Several polyphenols, flavonoids and other components from spices, algae and other sources are potential hormetins that may act via hormesis. Stress response pathways that can be analyzed for screening potential hormetins for use in cosmetics and cosmeceuticals include heat shock response, autophagy, DNA damage response, sirtuin response, inflammatory response and oxidative stress response.
Abstract: Tamarind seed polysaccharide (TSP) is a xyloglucan of vegetable origin, recently proposed for the cosmetic and pharmaceutical market as a “green” alternative to hyaluronic acid. In this study, TSP water dispersions, at different concentrations, were characterized by means of rheological measurements, both in continuous and oscillatory flow conditions. The results were compared with those of hyaluronic acid of two different molecular weights. The results pointed out the close rheological behaviors between TSP and hyaluronic acid with comparable molecular weight. Afterwards, the structural features of binary and ternary polysaccharide associations prepared with TSP, hyaluronic acid (very high MW) and dehydropolysaccharide gum, a modified xanthan gum, with high stabilizing properties, were investigated. The rheological properties were significantly affected by the polysaccharide ratios in the mixture, suggesting that the combination of TSP with other polymers can lead to a modulation of the texture and functional properties of cosmetics.
Abstract: Catalytically active titanium dioxide is conventionally used as a white pigment for cosmetics, but undesirably induces a certain degree of decomposition of sebum on the skin on exposure to ultraviolet radiation in sunlight. In this work, titanium phosphates were prepared as a novel white pigment for cosmetics using titanium sulfate and phosphoric acid at various temperatures, with/without ultrasonic treatment. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the phosphates were evaluated. These titanium phosphates had less photocatalytic activity than titanium dioxide, which should be beneficial for protecting sebum on the skin. Samples prepared with ultrasonic treatment had lower visible light absorption than those not subjected to ultrasonication. The sample prepared at 40 °C with ultrasonic treatment had higher moisture retention capacity than those prepared under other conditions. Samples prepared at 40 °C had lower slipping resistance than samples prepared at 7 °C.
Abstract: The aim of this study was to evaluate the influence of the depth of the dermis on the measured collagen and elastin levels and to establish the correlation between the amount of these two extracellular matrix (ECM) components and age. Multiphoton Microscopy (MPM) that measures the autofluorescence (AF) and second harmonic generation (SHG) was used to quantify the levels of elastin and collagen and to determine the SAAID (SHG-to-AF Aging Index of Dermis) at two different skin depths. A 50 MHz ultrasound scanner was used for the calculation of the Sub Epidermal Non Echogenic Band (SENEB). The measurements of the skin mechanical properties were done with a cutometer. All measurements were performed on two groups of 30 healthy female volunteers. The MPM showed a decrease of the quantity of collagen and elastin as a function of depth of the dermis as well as age. The SAAID was lower for the older skin in the deeper dermis. Ultrasound imaging revealed a significant decrease of SENEB as a function of aging. The mechanical properties confirmed a loss of cutaneous elasticity and firmness. Although multiphoton microscopy is a powerful technique to study the characteristics of the dermis and its age-related damage, the location of the measurements (depth) remains very important for the validation of these variations. These variations do not seem to be homogeneous according to the part of the dermis that is studied.
Abstract: Studies have shown that liquid crystals structurally resembling the intercellular lipids in the stratum corneum can beneficially affect the skin when applied topically by stimulating the skin’s natural regenerative functions and accelerating epidermal turnover. In the present study, the effects of applying low concentrations of a liquid crystal gel of our own creation were evaluated using epidermal thickening in mouse skin as an assay for effective stimulation of epidermal turnover. A liquid crystal gel was also applied topically to human facial skin, and analysis was conducted using before-and-after photographs of age spots, measurements of L* values that reflect degree of skin pigmentation, single-layer samples of the stratum corneum obtained via tape-stripping, and measurements of trans-epidermal water loss that reflect the status of the skin’s barrier function. The results suggested that cost-effective creams containing as low as 5% liquid crystal gel might be effective and safely sold as skin care products targeting age spots and other problems relating to uneven skin pigmentation.