Uneven skin pigmentation is a significant cosmetic concern, and the identification of topically applicable molecules to address this issue is of general interest. We report that the tetrapeptide PKEK (Pro-Lys-Glu-Lys) can exert skin whitening effects based on one in vitro and four double-blinded vehicle-controlled in vivo studies. (i) Treatment of human keratinocytes with PKEK significantly reduced UVB-stimulated mRNA expression of interleukin (IL)-6, IL-8 and TNF-α and, most importantly, proopiomelanocorticotropin (POMC), i.e. a gene encoding the pigmentation-inducing soluble mediator α- (α-MSH). (ii) PKEK treatment significantly inhibited UVB-induced upregulation of genes encoding for IL-1α, IL-6, IL-8, TNF-α as well as POMC and tyrosinase in 10 healthy volunteers pretreated with PKEK for 4 weeks once daily. (iii) In a study enrolling 39 Caucasian women, facial pigment spots significantly faded after 6 weeks when PKEK was combined with the skin whitener sodium ascorbyl phosphate (SAP), whereas PKEK or SAP alone led to less pronounced fading of the pigment spots. (iv) Addition of PKEK enhanced the skin whitening potency of a SAP-containing preparation if applied for 8 weeks to the back of hands of 19 Caucasians. (v) 27 Japanese women were treated on their faces twice daily with an SAP only or a PKEK+SAP-containing formulation for 8 weeks. Application of PKEK+SAP significantly reduced skin pigmentation by 26% and by 18% according to SCINEXA score. We demonstrate that PKEK has the capacity to reduce UVB-induced skin pigmentation and may be suited to serve as a skin tone-modulating agent in cosmetic products.
species while protecting the beneficial flora. Using a quick and reliable in vitro screening method we found several plant extracts (e.g. Ginseng or Black currant) which inhibit the inflammation-causing bacterium Propionibacterium acnes, but do not affect beneficial species like coagulase-negative staphylococci. In addition, it could also be demonstrated that a prebiotic product line for treatment of inflamed (or acne prone) skin showed the predicted effects on the microflora composition in a first in vivo trial, i.e. decrease of Propionibacterium acnes at a constant level of total bacteria. After 3 weeks, the microflora of 91% of the volunteers had been rebalanced in this way. Furthermore, these formulations have been shown to exhibit excellent skin compatibility compared to an antibacterial product. Thus, prebiotic substances have the potential to provide a gentle and sustainable alternative to undirected antibacterial ingredients which can cause irritation, and frequently only show short time effects.A product's packaging and claimed efficacy may stimulate pleasant emotions during the use of cosmetics, thus enhancing their perceived benefits. The aim of this study was to evaluate if smart packaging and strongly claimed efficacy attributes can influence the objectively measured efficacy, allowing a true placebo effect to be associated with a given cosmetic treatment. A marketed anti-aging gluconolactone-based formulation was selected for the study and packaged both in a fancy sophisticated jar and in an unbranded plain container. Thirty-six female volunteers (age range: 30-55 years) with facial photoageing were selected for the study and randomly assigned to the fancy or plain packaged product. Pre-agreed messages aimed at extolling the product's cosmetic effects accompanied delivery of the fancypackaged product to panellists. The given product was applied to the face twice a day for 8 weeks. Instrumental measurements of the skin colour (a* and L* parameter), skin capacitance, skin tensile properties (R0, R2, R6), skin thickness and skin microrelief parameters (Ra and Rz) were taken at baseline and after 4 and 8 weeks of use. Clinical and subjective evaluations were also carried out at each control visit. Moreover, the amount of cream consumed during usage was calculated by weighing the given jars at each visit. Statistical analysis of the data obtained showed a significant improvement in all instrumental parameters for both groups ('fancy' and 'plain' packaging), although no significant differences were detected between the two groups at any time. The improvement was higher in the 'plain' group for most instrumental parameters except for micro-relief parameters where the outcome was better in the 'fancy' group. Promotion of facial muscle relaxation deriving from the application of the fancy-packaged cream could be a possible explanation for this finding. Also the product's efficacy and sensory properties were perceived with a higher positive impact in the fancy group. The better performance of the plain packag...
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