Abstract: Whitening cosmetics with anti-melanogenesis activity are very popular worldwide. Many companies have tried to identify novel ingredients that show anti-melanogenesis effects for new product development. Among many plant-derived compounds, polyphenols are thought to be one of the most promising anti-melanogenesis ingredients. In order to prepare effective whitening polyphenols, 3,3,4,5,7-pentahydrosyflavone (quercetin) has been widely researched and applied to commercial products because it is present in high levels in many edible plants. Quercetin is thus a representative polyphenol and has recently gained attention in the cosmetics field. There are many controversies, however, regarding the effect of quercetin, based on in vitro studies, cell line experiments, and human trials. In this review, toxicity and efficacy data for quercetin and its derivatives in various experimental conditions (i.e., various cell lines, concentration ranges, and other parameters) were examined. Based on this analysis, quercetin itself is shown to be ineffective for hypopigmentation of human skin. However, a few types of quercetin derivatives (such as glycosides) show some activity in a concentration-dependent manner. This review provides clarity in the debate regarding the effects of quercetin.
Abstract: For several decades, the European Union (EU) has amongst its many tenets and principles the aim, enshrined in an EU Directive, that cosmetic products should not cause harm to the consumer. To a great extent, this is been successful, although it is noteworthy that the frequency of contact allergy to a number of ingredients commonly found in cosmetics has remained stubbornly high. Perhaps because of this, but certainly because of the drive by the European Commission towards better, more streamlined, regulation, the Directive was recast into a Regulation, usually referred to as the EU Cosmetics Regulation ((EC) No 1223/2009). As with the Directive, for each and every cosmetic product placed on the consumer market in the EU, a safety assessment is required. The Regulation requires that a dossier is prepared detailing the composition of the product, the safety of each of its ingredients, as well as an evaluation of overall product safety. This has to be completed by suitably trained and qualified assessors. Also relevant to cosmetic products are the general regulations pertaining to chemicals used in the EU where again many details of the toxicological profile must be ascertained and reviewed. On this basis, it should be possible to ensure that the extent of contact allergy attributed to cosmetic products declines. However, legislation is one thing, but it is also necessary to ensure that the cosmetic industry safety assessment process is completed in a rigourous manner (or even done at all) and that demands enforcement of the legislation.
Abstract: The paper provides an overview of existing Integrated Testing Strategies (ITS) for assessing hazard and potency of skin sensitization. The ITS research is active, diverse and constantly evolving as new assays are being developed and new mechanistic insights are discovered. Despite the need to assess potency, the majority of the ITS approaches developed to date assess hazard only. Reasons for this situation are analyzed and include, for example, the dynamic range of existing alternative assays versus the range of in vivo responses, but also sporadic use of kinetic information and molar units. Depending on the application, regulatory or product development, standardized and nonstandard ITS approaches will be developed. Challenges to practical applications, with focus on regulatory are discussed.
Abstract: The stratum corneum (SC), the most superficial layer of the skin, is directly responsible for the skin’s barrier function. The intercellular lipids in the SC play an important role in the regulation of the skin’s water-holding capacity. The modification of the intercellular lipid organization and composition may impair these properties. The aim of the present study is to describe a new in vitro approach of the repairing capacity evaluation of lipid formulations on skin with the use of absorption and desorption curves. The formulations were applied on lipid-extracted SC, and the possible SC reparation was assessed with the use of a thermogravimetric balance (DVS). Moisture absorption/desorption experiments proved to be adequate for the evaluation of the repairing capacity of formulations applied on damaged skin. Besides, freeze-substitution transmission electron microscopy (FSTEM) images showed some lipid bilayers, indicating a lipid bilayer reconstitution due to the applied formulations.
Abstract: Up to today, product safety evaluation in the EU is predominantly based on data/information on their individual ingredients. Consequently, the quality and reliability of individual ingredient data is of vital interest. In this context, the knowledge about skin sensitization potential is an explicit need for both hazard and risk assessment. Proper skin sensitization data of the individual chemicals is essential, especially when dermal contact is intended, like for cosmetics. In some cases, e.g., in the presence of irritating chemicals, the combination of individual ingredients may also need to be evaluated to cover possible mixture effects. Today, it seems unlikely or even impossible that skin sensitization in humans can be adequately described by a single test result or even by a simple combination of a few data points (in vivo or in vitro). It is becoming evident that a set of data (including human data and market data) and knowledge about the ingredient’s specific sensitizing potency needs to be taken into account to enable a reliable assessment of skin sensitization. A more in-depth understanding on mechanistic details of the Adverse-Outcome-Pathway of skin sensitization could contribute key data for a robust conclusion on skin sensitization.
Abstract: Kligman first coined the term telogen effluvium (TE) in 1961 to describe the state of increased shedding of otherwise normal telogen hairs. TE may be primary or secondary to a wide variety of potential triggers including febrile illness, drugs, thyroid disorders, and child birth. The diagnosis of secondary TE can be made by identifying known triggers from the history in the 3–4 months preceding the onset of increased hair shedding and by investigating to exclude endocrine, nutritional, or auto immune aetiologies. Scalp biopsy to identify the earliest stages of androgenetic alopecia may be required in some cases. Primary TE may be acute or chronic. In acute TE, the shedding resolves within 3–6 months and the hair density recovers completely. In chronic TE, the shedding can continue with minor fluctuations in severity for decades. In this review, possible causative factors, pathogenesis, clinical presentations and treatment options are discussed.