Annual Review of Cosmetic Ingredient Safety Assessments—2002/20031

Activation of retinoic acid-related orphan receptor γ(t) by parabens and benzophenone UV-filters

Retinoic acid-related orphan receptor γt (RORγt) regulates immune responses and its impaired function contributes to inflammatory and autoimmune diseases and may promote skin cancer. Synthetic inverse RORγt agonists block the production of Th17-associated cytokines including interleukin (IL)-17A and IL-22 and are under investigation for treatment of such pathologies. Unintentional RORγt activation in skin, following exposure to environmental chemicals, may promote inflammatory skin disease. Parabens and UV-filters, frequently used as additives in cosmetics and body care products, are intensively inspected for endocrine disrupting properties. This study assessed whether such compounds can interfere with RORγ activity using a previously established tetracycline-inducible reporter gene assay in CHO cells. These transactivation experiments revealed hexylparaben, benzylparaben and benzophenone-10 as RORγ agonists (EC50 values: 144 ± 97 nM, 3.39 ± 1.74 µM and 1.67 ± 1.04 µM, respectively), and they could restore RORγ activity after suppression by an inverse agonist. Furthermore, they enhanced RORγt-dependent transcription of the pro-inflammatory IL-17A and/or IL-22 genes in the murine T-cell model EL4. Virtual screening of a cosmetics database for structurally similar chemicals and in vitro testing of the most promising hits revealed benzylbenzoate, benzylsalicylate and 4-methylphenylbenzoate as RORγ agonists (low micromolar EC50 values). Moreover, an analysis of mixtures of the newly identified RORγ agonists suggested additive effects. This study presents novel RORγ(t) agonistic structural scaffolds. By activating RORγ(t) the identified parabens and UV-filters may potentially aggravate pathophysiological conditions, especially skin diseases where highest exposure of such chemicals can be expected. Follow-up studies should assess whether such compounds, either alone or as mixtures, can reach relevant concentrations in tissues and target cells to activate RORγ(t) in vivo.

Enhanced Disrupting Effect of Benzophenone-1 Chlorination Byproducts to the Androgen Receptor: Cell-Based Assays and Gaussian Accelerated Molecular Dynamics Simulations

Benzophenone-1 (BP-1), one of the commonly used ultraviolet filters, has caused increasing public concern due to frequently detected residues in environmental and recreational waters. Its susceptibility to residual chlorine and the potential to subsequently trigger endocrine disruption remain unknown. We herein investigated the chlorination of BP-1 in swimming pool water and evaluated the endocrine disruption toward the human androgen receptor (AR). The structures of monochlorinated (P1) and dichlorinated (P2) products were separated and characterized by mass spectrometry and ¹H-¹H NMR correlation spectroscopy. P1 and P2 exhibited significantly higher antiandrogenic activity in yeast two-hybrid assays (EC₅₀, 6.13 μM and 9.30 μM) than did BP-1 (12.89 μM). Our 350 ns Gaussian accelerated molecular dynamics simulations showed the protein dynamics in a long-time scale equilibrium, and further energy calculations revealed that although increased hydrophobic interactions are primarily responsible for enhanced binding affinities between chlorinated products and the AR ligand binding domain, the second chloride in P2 still hinders the complex motion because of the solvation penalty. The mixture of BP-1-P1-P2 elicited additive antiandrogenic activity, well fitted by the concentration addition model. P1 and P2 at 1 μM consequently downregulated the mRNA expression of AR-regulated genes, NKX3.1 and KLK3, by 1.7-9.1-fold in androgen-activated LNCaP cells. Because chlorination of BP-1 occurs naturally by residual chlorine in aquatic environments, our results regarding enhanced antiandrogenic activity and disturbed AR signaling provided evidence linking the use of personal care products with potential health risks.

Impacts of UV Filters in Mytilus galloprovincialis: Preliminary Data on the Acute Effects Induced by Environmentally Relevant Concentrations

Ultraviolet (UV) filters are present in a broad range of personal hygiene products, which may be transported via aquatic environments and domestic wastewaters due to inefficient treating station sewage removal and direct human contact. The aim of the present study was to evaluate the potential effects of a UV filter, in particular benzophenone-3 (BP3) (also known as oxybenzone) on the mussel species Mytilus galloprovincialis. Mussels were exposed to this organic substance for 96 h in environmentally relevant concentrations (10, 100, and 1000 ng/L). After exposure, biomarkers related with the mussels’ metabolism and oxidative stress were evaluated. The results revealed significantly higher activity of electron transport system and energy reserves (glycogen and protein (PROT)) at the intermediate concentration of 100 ng/L, suggesting that at lower concentrations mussels’ metabolism was not activated due to low stress. Conversely, at the highest concentration (1000 ng/L), mussels were no longer able to continue to increase their metabolic activity. Higher metabolic capacity was accompanied by increased PROT content associated with increased enzyme production to activate their antioxidant system. Nevertheless, at the highest concentration, cellular damage occurred as a consequence of ineffective activation of antioxidant and biotransformation enzymes. The results of the present study address uncertainties that are fundamental to the environmental risk assessment and management of these economically important near-shore bivalves and other marine species. Although an acute exposure was performed, alterations observed indicate the negative impacts of BP3 towards marine bivalves, which could be enhanced after longer exposure periods or if mussels are simultaneously exposed to other stressors (e.g., other pollutants or climate change related factors). The present study may thus contribute to the definition of fundamental knowledge for the establishment of appropriate regulatory guidelines and practices that ensure the preservation and sustainability of biological resources, allowing for prediction and mitigation of the impacts from these compounds.

Sunscreen-induced expression and identification of photosensitive marker proteins in human keratinocytes under UV radiation

Solar ultraviolet (UV) radiation is the main factor of photocarcinogenesis, photoaging, and photosensitivity; thus protection from biological damaging UV radiation is a concern. Sunscreens containing UV filters are the most preferred means of photoprotection but the safety and efficacy of UV filters are in question. Benzophenone (BP) and its derivatives, namely, benzophenone 1 (BP1), is commonly used in sunscreens as a UV blocker. The aim of this study was to assess the effects of BP and BP1 on the differential expression of proteins in human keratinocytes (HaCaT cells) under exposure to ultraviolet A radiation. Photosensitive proteins were screened from HaCaT cells by two-dimensional (2-D) gel electrophoresis, and identification of these differentially expressed proteins was performed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF)/TOF mass spectrometry. Protein identification was performed using the search program MASCOT and a database made of SUMO and GhJMJ12 amino acid sequences. Our results showed that the proteins involved directly or indirectly in apoptosis are 70 kDa heat shock protein, long-chain specific acyl-CoA dehydrogenase, serine/threonine-protein kinase, and FAM78A protein, which were upregulated in comparison to control HaCaT cells. The expressions of binding immunoglobulin protein, podocalyxin-like protein, actin, cytoplasmic, and calreticulin precursors were downregulated. The altered protein expression indicated that cell growth arrest and apoptosis were potential mechanisms of cytotoxicity and genotoxicity of BPs. The results of 2-D gel electrophoresis followed by mass spectrometry showed expression of novel proteins involved in promoting or initiating apoptotic pathways. Hence, we conclude that BPs should be avoided as a UV blocker from sunscreens because of its potential to promote apoptotic proteins in human skin keratinocytes.

Feminine Hygiene Products-A Neglected Source of Phthalate Exposure in Women

Phthalates have been associated with reproductive toxicity and precocious puberty in females, but the occurrence of these toxicants in feminine hygiene products is rarely reported. In this study, eight phthalates were determined in 120 feminine hygiene products (56 feminine care products and 64 sanitary napkins) collected from China. Phthalates were found in 86% and 98% of feminine care products and sanitary napkins, respectively, with the total concentrations varying between not detectable and 813 μg/g (median: 0.26 μg/g) and 0.25 and 8.76 μg/g (1.43 μg/g), respectively. Diethyl phthalate, dibutyl phthalate, and bis(2-ethylhexyl)phthalate were the major compounds, accounting for >60% of the total concentrations. The plastic materials used on the top and bottom layers and the hot melt adhesive used during the manufacturing process are the potential sources of phthalates in sanitary napkins. The range of daily exposure doses of phthalates in women from the use of feminine care products and sanitary napkins was <0.001-0.156 μg/kg-bw/day and <0.001-0.731 μg/kg-bw/day, respectively. Sanitary napkins contributed to 8.2% of the total exposure, and the levels of exposure to several phthalates from sanitary napkins were much higher than those reported from indoor dust ingestion but were lower than those of dietary intakes. Our study confirmed a new source of women's exposure to phthalates, sanitary napkins.

Evaluating the potential genotoxicity of phthalates esters (PAEs) in perfumes using in vitro assays

We previously reported high levels of phthalate esters (PAEs) added as solvents or fixatives in 47 brands of perfumes. Diethyl phthalate was the most abundant compound (0.232-23,649 ppm), and 83.3% of the perfumes had levels >1 ppm, the threshold limit cited by a Greenpeace investigation. All samples had dimethyl phthalate levels higher than its threshold limit of 0.1 ppm, and 88, 38, and 7% of the perfumes had benzyl butyl phthalate, di(2-ethylhexyl) phthalate, and dibutyl phthalate levels, respectively, above their threshold limits. The role of PAEs as endocrine disruptors has been well documented, but their effect on genotoxic behavior has received little attention. We used in vitro single-cell gel electrophoresis (comet) and micronucleus (MN) assays with human lymphoblastoid TK6 cells to evaluate the genotoxic potency of 42 of the same perfumes and to determine its association with PAEs. All perfumes induced more DNA damage than a negative control (NEG), ≥ 90% of the samples caused more damage than cells treated with the vehicles possibly used in perfume's preparations such as methanol (ME) and ethanol (ET), and 11.6% of the perfumes caused more DNA damage than a positive control (hydrogen peroxide). Chromosome breakage expressed as MN frequency was higher in cells treated with 71.4, 64.3, 57.1, and 4.8% of the perfumes than in NEG, cells treated with ME or ET, and another positive control (x-rays), respectively. The genotoxic responses in the comet and MN assays were not correlated. The comet assay indicated that the damage in TK6 cells treated with five PAEs at concentrations of 0.05 and 0.2 ppm either individually or as a mixture did not differ significantly from the damage in cells treated with the perfumes. Unlike the comet assay, the sensitivity of the MN assay to PAEs was weak at both low and high concentrations, and MN frequencies were generally low. This study demonstrates for the first time the possible contribution of PAEs in perfumes to DNA damage and suggests that their use as solvents or fixatives should be regulated. Other ingredients with mutagenic/genotoxic properties, however, may also have contributed to the DNA damage. Future studies should focus on applying a series of assays that use different cellular models with various endpoints to identify the spectrum of genotoxic mechanisms involved.

Safety and Efficacy of Nail Products

Over the past several decades, the commercialization of nail cosmetics has increased. From nail polishes to artificial nails, different methods of nail beautification have become popularized. However, the impact of these products remains largely unknown. Governments have passed legislation in attempts to regulate nail cosmetics, but these regulations may not be adequate and are difficult to enforce. Knowledge of the safety and efficacy of nail products remains limited due to the relative dearth of literature published on the topic. This review serves to summarize and interpret the data available regarding common nail products and their safety and efficacy. Nail products such as nail polish, nail polish removers, and artificial nails have shown to have some adverse effects through case reports and studies. Harmful substances such as toluenesulfonamide-formaldehyde resin and methacrylates have been identified in commercial nail products, leading to several adverse effects, but in particular, allergic contact dermatitis. Exposure to substances such as acetonitrile found in removers may have more toxic and caustic effects, especially if ingested. In addition, for nail technicians there are negative effects linked with occupational exposure. Compounds used in nail products may become aerosolized and lead to asthma, eye and throat irritation, and even neurocognitive changes.

Determination and confirmation of isopropyl p-toluenesulfonate in cosmetics by HPLC-diode array detector method and GC-MS

OBJECTIVE

Isopropyl p-toluenesulfonate (IPTS) is a potentially genotoxic by-product formed during the esterification of palm oil-based palmitic and palm kernel oil-based myristic acid with isopropanol to produce isopropyl palmitate or isopropyl myristate. There are no methods described for the analysis of IPTS in cosmetic products. In this work, we have established a simple, precise and accurate method to determine the presence and level of IPTS in various finished cosmetic products which contain palm-based esters in their formulations.

METHODS

An Agilent 1200 series high-performance liquid chromatography (HPLC) unit using a diode-array detector (DAD) has been employed and optimized to detect IPTS in cosmetic products. For the separation, a reverse-phase Hypersil Gold C8 column (5 μm, 4.6 mm i.d. 250 mm) 5 mM tetrabutylammonium phosphate buffer 50 : 50, (v/v) solution in acetonitrile as mobile phase, in isocratic mode and a flow rate of 0.8 mL min^-1 were used. A second method using a gas chromatography/mass selective detector GC-MSD was also developed to confirm the IPTS identity in the cosmetic products.

RESULTS

Recoveries of IPTS from cosmetic matrices such as a lotion, cleansing milk and a cream ranged from 94.0% to 101.1% with <5% relative standard deviation (%RSD) showing good accuracy and repeatability of the method. The six-point calibration curves (determined over the range 0.5-50 μg mL^-1 ) have a correlation coefficient of 0.9999 (based on HPLC peak area) and 0.9998 (based on HPLC peak height). The intra- and interday precisions (measured by the %RSD) of the method were <2% and <5%, respectively, indicating that the developed method is reliable, precise and reproducible. The detection and quantification limit of the method were found to be 0.5 μg mL^-1 and 1.6 μg mL^-1 , respectively. Analyses of 83 commercial cosmetics showed no presence of IPTS.

CONCLUSIONS

The validation data indicated that this method was suitable for the quantitative analysis of IPTS in commercial cosmetics. This method is applicable for analyses of trace levels of IPTS in cosmetics and has the advantage of using only simple sample preparation steps.