Contact and photocontact allergy to octocrylene: a review

Environmental implications and nanotechnological advances in octocrylene-enriched sunscreen formulations: A comprehensive review

Ultraviolet (UV) radiation is a major contributor to skin aging, cancer, and other detrimental health effects. Sunscreens containing FDA-approved UV filters, like avobenzone, offer protection but suffer from photodegradation and potential phototoxicity. Encapsulation, antioxidants, and photostabilizers are strategies employed to combat these drawbacks. Octocrylene, an organic UV filter, utilizes nanotechnology to enhance sun protection factor (SPF). This review examines recent literature on octocrylene-enriched sunscreens, exploring the interplay between environmental impact, nanotechnological advancements, and clinical trial insights. A critical focus is placed on the environmental consequences of sunscreen use, particularly the potential hazards UV filters pose to marine ecosystems. Research in the Mediterranean Sea suggests bacterial sensitivity to these filters, raising concerns about their integration into the food chain. This review aims to guide researchers in developing effective strategies for photostabilization of UV filters. By combining encapsulation, photostabilizers, and antioxidants, researchers can potentially reduce phototoxic effects and contribute to developing more environmentally friendly sunscreens.

UV filters in everyday cosmetic products, a comparative study

Today, UV filters are found as contaminants in a variety of biological fluids and environment, e.g. in vegetable crops and surface water. This is because UV filters are widely used in everyday products. In this context, we focused this study on cosmetic products, in order to assess the importance of this source of contamination. The study of 742 cosmetic products, excluding actual sunscreen products, but including hygiene, personal care and make-up products and perfumes revealed that the most common UV filters present are butyl methoxydibenzoylmethane (90 products or 12.1% of products tested), octyl methoxycinnamate (75 products or 10.1% of products tested), octocrylene (62 products or 8.3% of products tested), octyl salicylate (43 products or 5.8% of products tested) and titanium dioxide (33 products or 4.4% of products tested). Very few UV filters are found in the hygiene products (only in 12 shampoos/conditioners and in 2 shower gels) and deodorants and toothpastes are completely free of them. Conversely, make-up and perfumes are frequently formulated with at least one UV filter. Seventy-five of the two hundred and forty-four (or 30.7%) skincare products studied contained at least one UV filter. 49.1 of the makeup products studied and 74.3% of perfumes contained it.

Synthesis and characterisation of novel composite sunscreens containing both avobenzone and octocrylene motifs

Avobenzone and octocrylene are popular sunscreen active ingredients. Experiments that probe the stability of avobenzone in binary mixtures with octocrylene are presented, together with the synthesis of a class of novel composite sunscreens that were designed by covalently linking avobenzone and octocrylene groups. Spectroscopy, both steady-state and time-resolved, of the fused molecules was performed to investigate the stability of the new molecules and their potential function as ultraviolet filters. Computational results are detailed for truncated versions of a subset of the molecules to reveal the energy states underlying the absorption processes of this new class of sunscreen. The results indicate that the combination of elements of the two sunscreen molecules into one molecule creates a derivative with good stability to UV light in ethanol and in which the main degradation pathway of the avobenzone component in acetonitrile is reduced. Derivatives containing p-chloro substituents are particularly stable to UV light.

Octocrylene: From Sunscreens to the Degradation Pathway during Chlorination Processes: Formation of Byproducts and Their Ecotoxicity Assessment

Octocrylene is an organic sunscreen whose main action is to absorb UVB radiation and short UVA wavelengths; it is used in various cosmetic products in order to provide an adequate sun-protection factor or to protect the cosmetic formulations themselves from UV radiation. This filter is believed to be a possible endocrine disruptor and is also questioned due to its allergic and/or photoallergic potential. However, it continues to be widely used, and it has been found in various environments, not least those of swimming pools, where it is evidently released by consumers, to the point that it is now considered an emerging micropollutant. The present investigation presents the possible chemical fate of octocrylene in the typical chlorination conditions of wastewater or swimming pools. A total of 11 disinfection byproducts were identified, and 6 were identified for the first time, and separated by HPLC. These products were identified through careful mass spectrometry studies and 1D and 2D NMR experiments. A formation mechanism has been proposed that justifies the chemical structures of all of the compounds identified. The ecotoxicological assessment of octocrylene and their products was carried out by employing Phaeodactylum tricornutum, Brachionus plicatilis and Aliivibrio fischeri as bioindicators. The ecotoxicity results reveal that toxic byproducts might be generated during the oxidation process, increasing the potential risk to the marine environment.

Occurrence of Allergens in Cosmetics for Sensitive Skin

Sensitive skin is characterized by symptoms such as stinging and tingling in response to stimuli that usually do not cause unpleasant sensations. Epidemiological studies show that individuals with sensitive skin are more prone to developing skin allergies, although the link between both conditions is unknown. Aiming to evaluate the presence of allergens in facial-skin products for sensitive skin, a pool of 88 cosmetic products from international brands marketed in pharmacies and parapharmacies was analyzed. A list of allergens identified in product labels was compiled and grouped according to their function. Fragrances were the most common allergens, followed by skin-conditioning agents, surfactants, and preservatives. Fragrances presenting the highest use percentages were linalool, benzyl alcohol, geraniol, and citronellol. Overall, the majority of cosmetic formulations were absent of fragrance allergens, being present only in 7% of products. Other allergens were found in most products (95%). This finding should be interpreted with caution, since many of these compounds are rare sensitizers and studies demonstrating their risk for individuals with sensitive skin are lacking. With this study, useful information for health professionals is provided to support their advice and to help consumers choosing cosmetic products.

Sunscreen filter octocrylene is a potential obesogen by acting as a PPARγ partial agonist

Octocrylene (OC) is an extensively prescribed organic ultraviolet B filter used in sunscreen products. Due to its extensive use, a significant level of OC is detected in marine and freshwater environments. Notably, the bioaccumulation of OC in aquatic biota may affect human health. In this study, the effect of OC on metabolism was investigated using the adipogenesis model of human bone marrow mesenchymal stem cells (hBM-MSCs). OC promoted adiponectin production during adipogenesis in hBM-MSCs compared to the vehicle-treated control (EC₅₀, 29.6 μM). In target identification, OC directly bound to peroxisome proliferator-activated receptor (PPAR) γ (Ki, 37.8 μM). OC-bound PPARγ also significantly recruited nuclear receptor coactivator proteins SRC-1 (EC₅₀, 54.1 μM) and SRC-2 (EC₅₀, 58.6 μM). In the molecular docking simulation study, the optimal ligand-binding mode of OC suggested that OC is a PPARγ partial agonist. A competitive analysis with a PPARγ full agonist pioglitazone revealed that OC acted as a PPARγ partial agonist. OC altered the gene transcription profile of lipid-metabolism associated enzymes in normal human keratinocytes, primarily exposed human cells after the application of sunscreens. In conclusion, OC is a potential metabolic disrupting obesogen.

Mechanistic photophysics and photochemistry of unnatural bases and sunscreen molecules: insights from electronic structure calculations

Photophysics and photochemistry are basic subjects in the study of light-matter interactions and are ubiquitous in diverse fields such as biology, energy, materials, and environment. A full understanding of mechanistic photophysics and photochemistry underpins many recent advances and applications. This contribution first provides a short discussion on the theoretical calculation methods we have used in relevant studies, then we introduce our latest progress on the mechanistic photophysics and photochemistry of two classes of molecular systems, namely unnatural bases and sunscreens. For unnatural bases, we disclose the intrinsic driving forces for the ultrafast population to reactive triplet states, impacts of the position and degree of chalcogen substitutions, and the effects of complex environments. For sunscreen molecules, we reveal the photoprotection mechanisms that dissipate excess photon energy to the surroundings by ultrafast internal conversion to the ground state. Finally, relevant theoretical challenges and outlooks are discussed.

Ultraviolet filter, fragrance and preservative allergens in New Zealand sunscreens

BACKGROUND/OBJECTIVES

Allergic contact dermatitis, photoallergic contact dermatitis and irritant reactions to sunscreens are common reasons for dermatology consultation. Patch testing for contact allergy relies on up-to-date knowledge of allergen exposures. The aim of this study was to investigate contact allergens and photoallergens in sunscreens commercially sold on the shelves of supermarkets and pharmacies in New Zealand.

METHODS

A comprehensive market data review of suppliers' websites was performed from March to August 2019 to obtain a list of the commonly sold sunscreens in our region. Ingredients were collated and analysed according to International Nomenclature of Cosmetic Ingredients (INCI) names. Ultraviolet (UV) filters, preservatives and fragrances were included for analysis. Place of sale and cost of sunscreens were also recorded.

RESULTS

Ninety-five sunscreens were analysed: 36% sold in supermarkets, 43% in pharmacies and the remainder available in both. The most frequent UV filters were butyl methoxydibenzoylmethane (contained in 70% of products) followed by octocrylene (63%) and homosalate (50%). The common photoallergen benzophenone 3 was found in 19% of products. Phenoxyethanol was the most common preservative (68%) followed by disodium EDTA (30%) and propylparaben (26%). Two sunscreens contained methylisothiazolinone. Sixty-one per cent contained at least one fragrance, the most frequent being limonene (17%) and linalool (13%). There was an average of 1.1 New Zealand baseline series allergens per product (range 0 to 6, standard deviation 1.27).

CONCLUSION

Common allergens including those with high sensitising potential were frequently found in New Zealand sunscreen. Knowledge of ingredients used by manufacturers is useful in dermatological assessment of skin contact reactions.

Contact allergy to fragrance mix I and its components in individuals with photocontact allergy to ketoprofen

BACKGROUND

Contact allergy to fragrance mix I (FM I) is over-represented in patients photoallergic to ketoprofen. The prevalence of contact allergy to two components of FM I, cinnamal and cinnamyl alcohol, in ketoprofen-photoallergic patients is higher than in dermatitis patients.

OBJECTIVE

To explore the prevalence of contact allergy to FM I and its individual components in patients with photocontact allergy to ketoprofen, and to compare with a dermatitis and the general population.

METHODS

Data on patch and photopatch tests performed between 2009-2018 were collected. Ketoprofen-photoallergic patients were compared with dermatitis patients and published data on the general population regarding the prevalence and the distribution of contact allergy to FM I and its components.

RESULTS

A higher prevalence of contact allergy to cinnamyl alcohol compared with cinnamal (23.3% vs 10.0%), and eugenol compared with isoeugenol (23.3% vs 6.7%), was observed in ketoprofen-photoallergic patients, while the relationship was the opposite in the dermatitis group (0.7% vs 1.05%; 0.4% vs 0.9%). The overall prevalence of contact allergy to several components of FM I was significantly higher in ketoprofen-photoallergic patients.

CONCLUSIONS

Contact allergy to FM I and many of its components is over-represented in patients photoallergic to ketoprofen compared with dermatitis patients and the general population.

Bikini textile contact dermatitis: A Sherlockian approach revealing 2.4-dichlorophenol as a potential textile contact allergen

BACKGROUND

Different textile constituents may act as allergens and/or irritants and provoke textile contact dermatitis (TCD).

OBJECTIVES

To report a case of TCD caused by ethylene glycol monododecyl ether and 2.4-dichlorophenol, present in a bikini.

METHODS

A woman presented with an eczematous, pruritic rash in the area of the bikini straps and back. Patch testing was performed with the European baseline, textile, sunscreen, and photo-patch series, the bikini "as is", and ethanol and acetone extracts of the bikini. Thin-layer chromatography (TLC) of the extracts and gas chromatography-mass spectrometry (GC-MS) analysis were used to elucidate the culprit agents.

RESULTS

Positive reactions were found to the bikini "as is" and to the ethanol and acetone extracts. Patch testing with TLC strips showed a strong reaction to spots-fractions 3 and 4. GC-MS was performed to identify substances in each fraction and those suspected to be skin sensitisers were patch tested. On day (D) 4 positive reactions to ethylene glycol monododecyl ether (irritant reaction) and 2.4-dichlorophenol (++) were observed.

CONCLUSION

A myriad of chemical compounds can be found in clothing. Ethylene glycol monododecyl ether and 2.4-dichlorophenol were identified as the potential culprits of this bikini TCD.

HIGHLIGHTS

We have combined chemical analyses (thin-layer chromatography and gas chromatography-mass spectrometry) to study a case of textile contact dermatitis. As such, the presence of a myriad of chemical compounds was found in a bikini, suggesting that clothing in general may become impregnated or contaminated by a wide range of external substances that may be harmful to the skin. Textile contact dermatitis could in this case be attributed to ethylene glycol monododecyl ether (CAS No. 4536-30-5) and 2.4-dichlorophenol (CAS No. 120-83-2), the latter not yet previously described as a textile contact allergen.

Toxic effects of octocrylene on zebrafish larvae and liver cell line (ZFL)

Octocrylene (OC) is a broad-spectrum ultraviolet-absorbing chemical used in sunscreen and other personal care products. Its health effects are a concern because it has been detected in water, fish, humans, and food chains. In vivo and in vitro investigations were performed in zebrafish (Danio rerio) larvae and a zebrafish liver cell line (ZFL), respectively, to understand the potential risks and molecular mechanisms of OC toxicity. The 96-h median lethal concentration (LC₅₀) of OC was determined to be 251.8 μM in larvae and 5.5 μM in ZFL cells. Quantitative real-time PCR (qRT-PCR) showed that OC induced the expression of genes for CYPs (CYP1A, CYP3A65), estrogen receptors (ERα, ERβ1, GPER), vitellogenin (VTG1), and sex determination (BRCA2, CYP19A, DMRT1, SOX9A), both in vitro and in vivo. A whole-transcriptome sequencing method was used to evaluate the gene expression profile of larvae exposed to OC. OC was found to mediate the biosynthesis of estrogens (such as estriol) and affect the antioxidant pathway (glutathione transferases and peroxisome). These findings clarify the toxic effects and molecular mechanisms of OC and support banning its use in cosmetics.

Exploring Mycosporine-Like Amino Acids (MAAs) as Safe and Natural Protective Agents against UV-Induced Skin Damage

Prolonged exposure to harmful ultraviolet radiation (UVR) can induce many chronic or acute skin disorders in humans. To protect themselves, many people have started to apply cosmetic products containing UV-screening chemicals alone or together with physical sunblocks, mainly based on titanium–dioxide (TiO₂) or zinc-oxide (ZnO₂). However, it has now been shown that the use of chemical and physical sunblocks is not safe for long-term application, so searches for the novel, natural UV-screening compounds derived from plants or bacteria are gaining attention. Certain photosynthetic organisms such as algae and cyanobacteria have evolved to cope with exposure to UVR by producing mycosporine-like amino acids (MAAs). These are promising substitutes for chemical sunscreens containing commercially available sunblock filters. The use of biopolymers such as chitosan for joining MAAs together or with MAA-Np (nanoparticles) conjugates will provide stability to MAAs similar to the mixing of chemical and physical sunscreens. This review critically describes UV-induced skin damage, problems associated with the use of chemical and physical sunscreens, cyanobacteria as a source of MAAs, the abundance of MAAs and their biotechnological applications. We also narrate the effectiveness and application of MAAs and MAA conjugates on skin cell lines.

The presence of benzophenone in sunscreens and cosmetics containing the organic UV filter octocrylene: A laboratory study

BACKGROUND

The reason why patients photosensitized to the drug ketoprofen (KP) may develop severe photoallergic skin reactions to octocrylene (OCT), an organic ultraviolet filter in sunscreens and cosmetics, remains largely unknown. OCT can be synthesized by using unsubstituted benzophenone (BP), a possible human carcinogen.

OBJECTIVES

To verify if, and to what extent, BP residues are present in OCT-containing consumer products.

METHODS

The raw material of OCT and 39 skincare products, of which 28 contain OCT, were chemically analysed for the presence of BP by means of liquid chromatography.

RESULTS

In the OCT raw material and in all 28 OCT-containing products the presence of BP could be demonstrated, mostly in concentrations above 10 ppm (0.001%), whereas a majority of OCT-free products (8/11, 73%) did not contain BP. Moreover, BP concentrations significantly increased, in a time- and temperature-dependent manner, likely due to the additional degradation of OCT.

CONCLUSIONS

Photoallergic contact dermatitis from OCT in patients photosensitized to KP might rely on residual BP impurities. Toxicological and ecological studies that evaluate the safety of OCT might also need to consider the concomitant presence of BP.

In vitro metabolism of sunscreen compounds by liquid chromatography/high-resolution tandem mass spectrometry

RATIONALE

Exposure to UV light can induce adverse effects on human health, such as photo-aging, immunosuppression, and cancer. Sunscreens are used to prevent the absorption of UV rays, but certain UV-filtering compounds have been shown to disrupt endocrine systems or act as carcinogens. To assess the effects of the exposure to such compounds, it is important to study the pathways by which they are biotransformed in the body.

METHODS

Liquid chromatography coupled to high-resolution tandem mass spectrometry (LC/HRMS/MS) was employed to evaluate the oxidative metabolism and, specifically, the formation of reactive metabolites of six active ingredients commonly used in sunscreen formulations: oxybenzone, avobenzone, homosalate, octisalate, octocrylene, and octinoxate. In vitro incubations were performed with human and rat liver microsomes in the presence of β-nicotinamide adenine dinucleotide phosphate and glutathione. An LC/HRMS/MS method was developed to identify metabolites employing a biphenyl reversed-phase column for separating parent molecules, metabolites, and glutathione (GSH) adducts.

RESULTS

Each tested compound resulted in the formation of several metabolites, including at least one GSH adduct. Compounds containing ester groups were hydrolyzed, and some metabolites of the free acid forms were also detected. High-resolution MS/MS data was crucial for the structural elucidation of metabolites and GSH adducts. Fragmentation pathways were proposed for all parent compounds, as well as each described metabolite and adduct.

CONCLUSIONS

The results of this study will help better understand the metabolism and detoxification pathways of these xenobiotics.

What is in? What is out? Updating the British Society for Cutaneous Allergy facial series

BACKGROUND

Allergic contact dermatitis (ACD) to cosmetics is widely reported. To ensure we are accurately diagnosing ACD, patch test series should be continually reviewed to identify relevant and emerging allergens and highlight those that are outdated. The current British Society for Cutaneous Allergy (BSCA) facial series recommends 26 allergens and was last modified in 2012.

OBJECTIVES

To review and update the BSCA facial series.

METHODS

We retrospectively reviewed the results from 12 UK and Ireland patch test centres' facial series from January 2016 to December 2017. We recorded the number of allergens tested in each centre and the detection rate for each allergen. Using a 0·3% positive rate as the inclusion threshold, we established which allergens in the BSCA facial series had positive patch test rates < 0·3% and > 0·3%. Allergens not in the BSCA facial series that had a positive patch test rate > 0·3% were identified.

RESULTS

Overall, 4224 patients were patch tested to the facial series. The number of allergens included in individual centres' facial series ranged from 24 to 66, with a total of 103 allergens tested across all centres. Twelve of the 26 allergens in the BSCA facial series had a positive patch test rate < 0·3% and 14 had a rate > 0·3%. Twenty-five allergens not recommended in the BSCA facial series had a positive patch test rate > 0·3%.

CONCLUSIONS

This audit has highlighted the significant variation in practice that exists among patch test centres, despite a recommended facial series. The BSCA facial series has been updated and now contains 24 allergens. Fifteen allergens remain, 11 allergens have been dropped and nine new allergens have been added.

Microbial biofilm formation and degradation of octocrylene, a UV absorber found in sunscreen

Octocrylene is a widely used synthetic UV absorber of sunscreens and found in several environments. Ecological consequences of the accumulation of UV filters are widely discussed. This is the first report revealing the microbial potential to transform octocrylene. A microbial community comprising four bacterial species was enriched from a landfill site using octocrylene as carbon source. From these microorganisms Mycobacterium agri and Gordonia cholesterolivorans were identified as most potent applying a new "reverse discovery" approach. This relies on the possibility that efficient strains that are already isolated and deposited can be identified through enrichment cultures. These strains formed massive biofilms on the octocrylene droplets. GC-MS analysis after cultivation for 10 days with M. agri revealed a decrease in octocrylene concentration of 19.1%. LC-MS/MS analysis was utilized in the detection and quantification of transformation products of octocrylene. M. agri thus represents an ideal candidate for bioremediation studies with octocrylene and related compounds.

Systemic availability of lipophilic organic UV filters through dermal sunscreen exposure

BACKGROUND

Chemical UV filters are common components in sunscreens and cosmetic products and used to protect the skin against harmful effects of sunlight like sunburn. However, the effectiveness of sunscreens in the prevention of skin cancer is in some parts still controversial. Meanwhile, questions about negative effects of the chemical UV filters on human health arise and request an effective risk assessment. Real-life exposure data in humans after application of these products are still rare. Thus, we explored whether and to what extent UV filters are absorbed through the skin into the human body.

MATERIAL AND METHODS

Plasma and urine samples from 20 healthy volunteers were collected before, during and after a real-life exposure scenario (1st application: 2 mg/cm²; 2nd and 3rd (after 2 and 4 h): 1 mg/cm² each) using a commercial sunscreen formulation for one day. These samples were analyzed for their content of the currently prominent UV filters octocrylene and avobenzone as well as 2-cyano-3,3-diphenylacrylic acid (CDAA) as the main octocrylene metabolite by using different liquid chromatography electrospray-ionization tandem mass spectrometric procedures.

RESULTS

Following dermal sunscreen exposure, avobenzone, octocrylene and CDAA reached concentrations up to 11 μg/L, 25 μg/L and 1352 μg/L in plasma. In urine detection rates of avobenzone and octocrylene were low while CDAA showed a high detection rate and reached up to 5207 μg/g creatinine. Kinetic models could be fitted for octocrylene and CDAA in plasma and CDAA in urine. Concentration peaks were reached between 10 and 16 h after first application and half-life periods were in the range of 1.5 to 2 days. The lipophilic UV filter octocrylene and its metabolite CDAA showed a much slower elimination than other more hydrophilic UV filters. Concordantly, the metabolite CDAA in particular showed a markedly increased renal excretion over the whole sampling period and indicated high internal exposure to OC.

DISCUSSION

Real-life sunscreen usage leads to considerable bioavailability of organic UV filters and their metabolites which is rarely seen for other environmental exposures. A combined monitoring of the parent compound and its metabolites is important to fully address internal exposure to the UV filter in humans. Considering the kinetic profiles a prolonged systemic release due to depot formation in skin and a potential accumulation through multi-day exposure is presumed. High in-vivo loads call for a critical toxicological assessment of the UV filters and their metabolites.

QM/MM Studies on the Photophysical Mechanism of a Truncated Octocrylene Model

Methyl 2-cyano-3,3-diphenylacrylate (MCDPA) shares the same molecular skeleton with octocrylene (OCR) that is one of the most common molecules used in commercially available sunscreens. However, its excited-state relaxation mechanism is unclear. Herein, we have used the QM(CASPT2//CASSCF)/MM method to explore spectroscopic properties, geometric and electronic structures, relevant conical intersections and crossing points, and excited-state relaxation paths of MCDPA in methanol solution. We found that in the Franck-Condon (FC) region, the V(¹ππ*) state is energetically lower than the V'(¹ππ*) state only by 2.8 kcal/mol and is assigned to experimentally observed maximum absorption band. From these two initially populated singlet states, there exist three nonradiative relaxation paths to repopulate the S₀ state. In the first one, when the V(¹ππ*) state is populated in the FC region, the system diabatically evolves along the V(¹ππ*) state into its minimum where the internal conversion to S₀ occurs. In the second one, the V'(¹ππ*) state is populated in the FC region and the system adiabatically overcomes a barrier of ca. 3.0 kcal/mol to approach the V(¹ππ*) minimum eventually leading to a V(¹ππ*)-to-S₀ internal conversion. In the third one, the V'(¹ππ*) state first hops via the intersystem crossing to the T₂ state, which then decays through the internal conversion to the T₁ state. The T₁ state is finally converted to the S₀ state via the T₁/S₀ crossing point. Our present work contributes to understanding the photophysics of OCR and its variants.

Drug and chemical induced photosensitivity from a clinical perspective

Drug photosensitivity is a relatively common occurrence and a range of mechanisms may be involved. Some of these mechanisms will be discussed, including the most common, that of drug phototoxicity. Different types of photosensitivity are addressed with respect to clinical presentation, mechanisms and additionally the contribution to our understanding through clinically directed investigations and regulatory requirements. Repeated controlled therapeutic use of drug phototoxicity, with psoralen-UVA (PUVA) photochemotherapy and photodynamic therapy (PDT) will also be discussed. Finally, the potential for drug-induced photocarcinogenesis will also be covered.

Effects of single exposure and binary mixtures of ultraviolet filters octocrylene and 2-ethylhexyl 4-(dimethylamino) benzoate on gene expression in the freshwater insect Chironomus riparius

Ultraviolet filters are used extensively in the production of many personal care and industrial products. These products can inadvertently pollute the environment through recreational activities. They have been associated with endocrine disruption in vertebrates but their effects in invertebrates are poorly understood. Chironomus riparius is a species of the dipteran order, with aquatic larvae that are frequently used in toxicity tests. Previously, we showed that octocrylene (OC) and 2-ethylhexyl 4-(dimethylamino) benzoate (OD-PABA) differentially affected the mRNA levels of the ecdysone receptor and Hsp70 genes. For a better understanding of their mode of action, transcriptional activity by real-time PCR was analyzed in fourth instar larvae exposed to OC, OD-PABA, or a binary mixture of both. We studied 16 genes related to the endocrine system, stress, the immune system, and biotransformation mechanisms to elucidate the putative interactions between these compounds. No response was observed for the genes involved in biotransformation, suggesting that enzymes other than cytochromes P450 and glutathione-S-transferases (GSTs) could get involved in transformation of these compounds. Similarly, no response was observed for endocrine-related genes while the stress gene HYOU1 was inhibited by OD-PABA, suggesting an effect in response to hypoxia. In addition, no significant interactions were observed following exposure to a binary mixture of these compounds. Overall, the results suggest a weak, acute response in different metabolic pathways and a lack of interaction between the compounds. Finally, new genes are identified in this organism, opening the possibility to analyze new cellular pathways as targets of toxicants.

Cinnamic acid derivatives in cosmetics: current use and future prospects

Cinnamic acid derivatives are widely used in cosmetics and possess various functions. This group of compounds includes both naturally occurring and synthetic substances. On the basis of the Cosmetic Ingredient Database (CosIng) and available literature, this review summarizes their functions in cosmetics, including their physicochemical and biological properties as well as reported adverse effects. A perfuming function is typical of many derivatives of cinnamaldehyde, cinnamyl alcohol, dihydrocinnamyl alcohol and cinnamic acid itself; these substances are commonly used in cosmetics all over the world. Some of them show allergic and photoallergic potential, resulting in restrictions in maximum concentrations and/or a requirement to indicate the presence of some substances in the list of ingredients when their concentrations exceed certain fixed values in a cosmetic product. Another important function of cinnamic acid derivatives in cosmetics is UV protection. Ester derivatives such as ethylhexyl methoxycinnamate (octinoxate), isoamyl p-methoxycinnamte (amiloxiate), octocrylene and cinoxate are used in cosmetics all over the world as UV filters. However, their maximum concentrations in cosmetic products are restricted due to their adverse effects, which include contact and a photocontact allergies, phototoxic contact dermatitis, contact dermatitis, estrogenic modulation and generation of reactive oxygen species. Other rarely utilized functions of cinnamic acid derivatives are as an antioxidant, in skin conditioning, hair conditioning, as a tonic and in antimicrobial activities. Moreover, some currently investigated natural and synthetic derivatives of cinnamic acid have shown skin lightening and anti-ageing properties. Some of them may become new cosmetic ingredients in the future. In particular, 4-hydroxycinnamic acid, which is currently indexed as a skin-conditioning cosmetics ingredient, has been widely tested in vitro and in vivo as a new drug candidate for the treatment of hyperpigmentation.

Mass fluxes per capita of organic contaminants from on-site sewage treatment facilities

This study is the first attempt to quantify environmental fluxes per capita of organic contaminants discharged from on-site sewage treatment facilities (OSSFs) in affected recipients. Five sites were monitored around the River Fyris in Sweden: three mainly affected by OSSFs and two mainly affected by municipal sewage treatment plants (STPs). Gas chromatography-mass spectrometry was used to determine environmental concentrations of 30 anthropogenic contaminants, including organophosphorus compounds, rubber and plastic additives, UV stabilizers, fragrances, surfactant ingredients and polycyclic aromatic hydrocarbons. Uni- and multivariate statistical analysis of the most frequently detected contaminants showed that median fluxes per capita of tris(1,3-dichloro-2-propyl) phosphate, tris(1-chloro-2-propyl) phosphate, tris(2-chloroethyl) phosphate, and n-butylbenzene sulfonamide were similar at OSSF and STP sites, but the mass fluxes per capita of tris-(2-butoxyethyl) phosphate, 2-(methylthio)benzothiazole, and galaxolide, were significantly lower (∼2-3-fold) at OSSF sites than at STP sites (Mann-Whitney, α = 0.05). Differences between these sites were larger in samples collected in summer and autumn than in samples collected in winter. Deviations likely originated from differences in fate processes and distances between source and sampling sites. Further studies are needed to characterize mass fluxes per capita of contaminants in waters that directly receive discharges from OSSFs.

Molecular photoprotection of human keratinocytes in vitro by the naturally occurring mycosporine-like amino acid palythine

Background

Solar ultraviolet radiation (UVR) induces molecular and genetic changes in the skin, which result in skin cancer, photoageing and photosensitivity disorders. The use of sunscreens is advocated to prevent such photodamage; however, most formulations contain organic and inorganic UVR filters that are nonbiodegradable and can damage fragile marine ecosystems. Mycosporine‐like amino acids (MAAs) are natural UVR‐absorbing compounds that have evolved in marine species for protection against chronic UVR exposure in shallow‐water habitats.

Objectives

To determine if palythine, a photostable model MAA, could offer protection against a range of UVR‐induced damage biomarkers that are important in skin cancer and photoageing.

Methods

HaCaT human keratinocytes were used to assess the photoprotective potential of palythine using a number of end points including cell viability, DNA damage (nonspecific, cyclobutane pyrimidine dimers and oxidatively generated damage), gene expression changes (linked to inflammation, photoageing and oxidative stress) and oxidative stress. The antioxidant mechanism was investigated using chemical quenching and Nrf2 pathway activation assays.

Results

Palythine offered statistically significant protection (P < 0·005) against all end points tested even at extremely low concentrations (0·3% w/v). Additionally, palythine was found to be a potent antioxidant, reducing oxidatively generated stress, even when added after exposure.

Conclusions

Palythine is an extremely effective multifunctional photoprotective molecule in vitro that has potential to be developed as a natural and biocompatible alternative to currently approved UVR filters.

What's already known about this topic?

Mycosporine‐like amino acids (MAAs) are photoprotective molecules found in marine organisms but there are few data on their ability to protect skin cells from the adverse effects of solar ultraviolet radiation (UVR).

The European Chemicals Agency (ECHA) is concerned about the potential adverse health and ecotoxic effects of eight of 16 commonly used sunscreen filters in Europe. The Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme has expressed similar concerns.

What does this study add?

Palythine, an MAA extracted from an edible seaweed, affords photoprotection against a wide range of adverse effects in HaCaT keratinocytes exposed to solar simulating and ultraviolet A radiation. Of note is protection against two types of DNA photolesions; cyclobutane pyrimidine dimers and 8‐oxo‐7,8‐dihydroguanine.

Palythine is also a potent antioxidant that offers protection even when added after UVR exposure.

What is the translational message?

MAAs should be considered for development as natural biocompatible sunscreens that may address the concerns of the ECHA and EEAP.

Linked Comment: https://doi.org/10.1111/bjd.16598.

https://goo.gl/Uqv3dl

In Vivo Human Skin Penetration Study of Sunscreens by Confocal Raman Spectroscopy

This research work mainly deals with the application of confocal Raman spectroscopic technique to study in vivo human skin penetration of sunscreen products, as there are a lot of controversies associated with their skin penetration. Healthy human volunteers were tested for penetration of two commercial sunscreen products into their volar forearm skin for a period of 2 h. Measurements were taken before and after application of these sunscreen products. All the confocal Raman spectra were pre-processed and then subjected to multivariate two-dimensional principal component analysis and classical least squares analysis to determine the skin penetration of these sunscreens in comparison to the "sunscreen product spectrum" which was considered as the control. Score plots of principal component analysis of confocal Raman spectra indicated clear separation between the spectra before and after application of sunscreen products. Loading plots showed the maximum differences in the spectral region from 1590 to 1626 cm^-1 where the characteristic peak of the pure sunscreen products was observed. Classical least squares analysis has shown a significant penetration to a depth of 10 μm in the volar forearm skin of healthy human volunteers for both these sunscreen products. The results confirm that the penetration of these tested sunscreen products was restricted to stratum corneum and also prove that confocal Raman spectroscopy is a simple, fast, nondestructive, and noninvasive semi-quantitative analytical technique for these studies.

Assessment of the general quality of sunscreen products available in Palestine and method verification of the sun protection factor using Food and Drug Administration guidelines

BACKGROUND

Sunlight exposure affects all skin types causing skin tanning, burns or even skin cancer. Sunscreens were invented to prevent these outcomes by scattering or absorbing the UV light.

AIMS

This study aimed to verify the effectiveness of Mansur method in SPF measurement and to find out how much reliable the labeled sun protection factor (SPF) value for the products that are imported to Palestine knowing that they are considered as cosmetics and they don't undergo tests by the Ministry Of Health (MOH).

MATERIALS

In this research, sun protection factor (SPF) was determined for 16 commercially available sunscreen products using Mansur equation which was also validated; moreover sunscreen classification, product phase determination and pH measurement were also done.

RESULTS

Sun protection factor values were mostly 50, 43.75% of the analyzed samples were close to the labeled SPF, 31.25% were under the labeled value, and 25% SPF value above the labeled value. All samples exhibited a pH close to skin pH. 62% of them were found to be O/W. Cosmetic companies and importers should focus on pediatric sunscreens, since only 12.5% are pediatric sunscreens.

CONCLUSIONS

Ministry Of Health should ask prove about the quality of an SPF value of sunscreens for final registration of these products. More instructions should be available on the label regarding the proper use especially, if they are not water proof.

Ketoprofen-induced photoallergic dermatitis

Drug-induced photosensitivity reactions are significant adverse effects. Ketoprofen is one of the most common drugs that can cause skin rash in sun-exposed areas. Non-steroidal anti-inflammatory drugs (NSAIDs), such as ketoprofen, are often used for a variety of symptoms, including pain and fever. An understanding of the presentation and clinical course of ketoprofen-induced photosensitivity is necessary to correctly diagnose and manage this condition. Ketoprofen-induced photosensitivity reactions usually present as photoallergic dermatitis, which is a cell-mediated immune process. The benzophenone moiety in ketoprofen plays a major role in ketoprofen's ability to act as a photosensitizer. Several agents, such as fenofibrate and octocrylene have been found to be associated with aggravation of ketoprofen-induced photoallergic dermatitis or cross-photosensitization, and these reactions result from structural similarities with ketoprofen. Treatment of ketoprofen-induced photoallergic dermatitis includes discontinuation of ketoprofen, topical or systemic corticosteroids and avoidance of sun exposure and agents known to exacerbate dermatitis. In conclusion, photoallergic dermatitis is a significant adverse effect of ketoprofen. Some agents known to worsen dermatitis may be found in sun protection products (notably, octocrylene in sunscreen). Educating the patient to avoid these products is critical to treatment. Since NSAIDs, such as ketoprofen, are used commonly for a variety of illnesses, drug-induced photoallergic dermatitis should be high on the differential in individuals using these medications who present with acute onset of a rash in sun-exposed areas.

Stability Study of Sunscreens with Free and Encapsulated UV Filters Contained in Plastic Packaging

Sunscreens play a fundamental role in skin cancer prevention and in protection against photo-aging. UV filters are often photo-unstable, especially in relation to their vehicles and, being lipophilic substances, they are able to interact with plastic packaging. Finally, UV filter stability can be significantly affected by the routine use of the product at high temperatures. This work aims to study the stability of sunscreen formulations in polyethylene packaging. Butyl methoxydibenzoylmethane and octocrylene, both in a free form and as encapsulated filters were chosen as UV filters. Stability evaluations were performed both in the packaging and on the formulations. Moreover, a further two non-destructive techniques, near-infrared (NIR) spectroscopy and a multiple light scattering technique, were also used to evaluate the stability of the formulation. Results demonstrated clearly that all of the pack underwent significant changes in its elastic/plastic behavior and in external color after solar irradiation. From the evaluation of the extractable profile of untreated and treated packaging material an absorption of 2-phenoxyethanol and octocrylene were shown. In conclusion, the results highlighted clearly that a reduction of the UV filter in the formulation packed in high-density polyethylene/low-density polyethylene (HDPE/LDPE) material can occur over time, reducing the protective effect of the product when applied to the skin.

Neurotoxic effect of active ingredients in sunscreen products, a contemporary review

Sunscreen application is the main strategy used to prevent the maladies inflicted by ultraviolet (UV) radiation. Despite the continuously increasing frequency of sunscreen use worldwide, the prevalence of certain sun exposure-related pathologies, mainly malignant melanoma, is also on the rise. In the past century, a variety of protective agents against UV exposure have been developed. Physical filters scatter and reflect UV rays and chemical filters absorb those rays. Alongside the evidence for increasing levels of these agents in the environment, which leads to indirect exposure of wildlife and humans, recent studies suggest a toxicological nature for some of these agents. Reviews on the role of these agents in developmental and endocrine impairments (both pathology and related mechanisms) are based on both animal and human studies, yet information regarding the potential neurotoxicity of these agents is scant. In this review, data regarding the neurotoxicity of several organic filters: octyl methoxycinnamate, benzophenone-3 and −4, 4-methylbenzylidene camphor, 3-benzylidene camphor and octocrylene, and two allowed inorganic filters: zinc oxide and titanium dioxide, is presented and discussed. Taken together, this review advocates revisiting the current safety and regulation of specific sunscreens and investing in alternative UV protection technologies.