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.

Sunscreen Safety and Efficacy for the Prevention of Cutaneous Neoplasm

Sunscreen is widely used for ultraviolet radiation protection. Studies validate sun protection factors (SPFs) to prevent ultraviolet (UV)-induced skin changes such as melanoma and squamous cell carcinoma (SCC). Few studies examine sunscreen's impact on endocrine and immune system dysregulation, the production of radical oxygen species, and whether the ingredients deteriorate under prolonged exposure. We present an investigation of sunscreen labels and how ingredients impact sun safety and human health. A review of the literature was conducted using Embase and PubMed to examine sunscreen safety, efficacy, and use to prevent UV-induced skin damage. Increasing sunscreen reapplication, wearing protective clothing, and limiting exposure can reduce the incidence of skin cancer. Inorganic sunscreens form barriers to block UV light, but without titanium dioxide (TiO2), they may not be advantageous due to their low UVA protection. Organic sunscreens absorb into the skin and provide a better feeling after application. Octocrylene and avobenzone are stable and provide UVA and UVB protection with minimal adverse effects. Oxybenzone is harmful to the neuroendocrine system and should be avoided. Titanium dioxide works for broad-spectrum UV protection and offers minimal adverse effects. Octocrylene and avobenzone are organic sunscreen ingredients that also provide a better feeling on the skin after application, which enables higher rates of use. Oxybenzone should be avoided.

Effects associated with exposure to the emerging contaminant octyl-methoxycinnamate (a UV-B filter) in the aquatic environment: a review

Given the increasing concern surrounding ultraviolet (UV) radiation-induced skin damage, there has been a rise in demand for UV filters. Currently, UV-filters are considered emerging contaminants. The extensive production and use of UV filters have led to their widespread release into the aquatic environment. Thus, there is growing concern that UV filters may bioaccumulate and exhibit persistent properties within the environment, raising several safety health concerns. Octyl-methoxycinnamate (OMC) is extensively employed as a UV-B filter in the cosmetic industry. While initially designed to mitigate the adverse photobiological effects attributed to UV radiation, the safety of OMC has been questioned with some studies reporting toxic effects on environment. The aim of this review to provide an overview of the scientific information regarding the most widely used organic UV-filter (OMC), and its effects on biodiversity and aquatic environment.

Prioritization of chemicals in personal care products based on persistent, bioaccumulative and toxic (PBT) potential: An Indian perspective

Numerous organic ingredients present in Personal care products (PCPs) are being detected in sewage which has a high potential to impact the environment. These compounds are called as Emerging contaminants (ECs) or Contaminants of emerging concern. However, the information on the source and occurrence of ECs present in PCPs is very minimal. Specifically, information on the persistence (P), bioaccumulation (B) and toxicity (T) is very scarce. The determination of PBT properties is a complex task given the magnitude of chemicals, thus it is necessary to have a tool to quickly screen and prioritize the most important compounds. Estimation Program Interface (EPI) Suite™ is one such tool authorized by United States Environmental Protection Agency (US EPA) for screening purposes. In the present study, several organic compounds present in the PCPs viz. body lotion, sunscreens, moisturizers, hair dyes, and some hair care products were identified and their PBT property was estimated. The results from the study indicate that the order of increasing occurrence of PBT chemicals is sunscreens > moisturizers > body lotion > hair care products > hair dyes. The prioritized compounds were given rank 1 (maximum concern) to rank 4 (minimum concern). From the results, the compounds octocrylene in sunscreens and butylphenyl methylpropional in body lotions were prioritized as Rank 1.

Organic ultraviolet absorbents in soils and typical plants from an industrial metropolis in China: Concentrations, profiles and environmental implications

There is accumulating evidence of the toxicity of organic ultraviolet absorbers (OUVAs); however, limited information is available regarding the presence of OUVAs in terrestrial environments and organisms. Therefore, this study was conducted to investigate the occurrence of 11 OUVAs in soils and typical plant species from an industrial metropolis in China. Total OUVA concentrations in soils ranged from 1.30 to 80.3 ng g-1 DW. Based on comparison with previously reported data, OUVA contamination in soil was not severe. Benzophenone and octocrylene were the dominant OUVAs in soils, with median contributions to total concentrations of 25% and 15%, respectively. Source assessment revealed that the observed OUVA contamination primarily originated from industrial activities and the use of personal care products. The concentration of 11 OUVAs in plants ranged from 159 to 4470 ng g-1 DW, at high levels. Our findings imply that great attention should be given to the presence of these chemicals in plants because of the risk they could pose as well as the potential for biomagnification as plants are eaten by insects and birds. Our results also indicate the necessity to further study the geochemical behavior of these chemicals in urban ecosystems in order to better manage the harmfulness to terrestrial ecological health caused by their exposure through the food chains.

New developments in sunscreens

Topical sunscreen application is one of the most important photoprotection tool to prevent sun damaging effects in human skin at the short and long term. Although its efficacy and cosmeticity have significantly improved in recent years, a better understanding of the biological and clinical effects of longer wavelength radiation, such as long ultraviolet A (UVA I) and blue light, has driven scientists and companies to search for effective and safe filters and substances to protect against these newly identified forms of radiation. New technologies have sought to imbue sunscreen with novel properties, such as the reduction of calorific radiation. Cutaneous penetration by sunscreens can also be reduced using hydrogels or nanocrystals that envelop the filters, or by binding filters to nanocarriers such as alginate microparticles, cyclodextrins, and methacrylate polymers. Finally, researchers have looked to nature as a source of healthier products, such as plant products (e.g., mycosporines, scytonemin, and various flavonoids) and even fungal and bacterial melanin, which could potentially be used as substitutes or enhancers of current filters.

Characteristic Photoprotective Molecules from the Sphagnum World: A Solution-Phase Ultrafast Study of Sphagnic Acid

A natural UV-absorbing chromophore extracted from sphagnum mosses, sphagnic acid, is proposed as a new natural support to chemical UV filters for use in cosmetic applications. Sphagnic acid is structurally related to the cinnamate family of molecules, known for their strong UV absorption, efficient non-radiative decay, and antioxidant properties. In this study, transient electronic absorption spectroscopy is used, in conjunction with steady-state techniques, to model the photodynamics following photoexcitation of sphagnic acid in different solvent systems. Sphagnic acid was found in each system to relax with lifetimes of ~200 fs and ~1.5 ps before generating a cis-isomer photoproduct. This study helps to elucidate the photoprotective mechanism of a new potential natural support to sunscreens, from a unique plant source.

Can short-term data accurately model long-term environmental exposures? Investigating the multigenerational adaptation potential of Daphnia magna to environmental concentrations of organic ultraviolet filters

Organic ultraviolet filters (UVFs) are contaminants of concern, ubiquitously found in many aquatic environments due to their use in personal care products to protect against ultraviolet radiation. Research regarding the toxicity of UVFs such as avobenzone, octocrylene and oxybenzone indicate that these chemicals may pose a threat to invertebrate species; however, minimal long-term studies have been conducted to determine how these UVFs may affect continuously exposed populations. The present study modeled the effects of a 5-generation exposure of Daphnia magna to these UVFs at environmental concentrations. Avobenzone and octocrylene resulted in minor, transient decreases in reproduction and wet mass. Oxybenzone exposure resulted in > 40% mortality, 46% decreased reproduction, and 4-fold greater reproductive failure over the F0 and F1 generations; however, normal function was largely regained by the F2 generation. These results indicate that Daphnia are able to acclimate over long-term exposures to concentrations of 6.59 μg/L avobenzone, ∼0.6 μg/L octocrylene or 16.5 μg/L oxybenzone. This suggests that short-term studies indicating high toxicity may not accurately represent long-term outcomes in wild populations, adding additional complexity to risk assessment practices at a time when many regions are considering or implementing UVF bans in order to protect these most sensitive invertebrate species.

Antioxidant-Activity-Guided Purification and Separation of Octocrylene from Saussurea heteromalla

Plants have been a source of medicine since ancient times, and such traditional medications are widely practiced nowadays. Saussurea heteromalla is widely used in traditional medicine in the Himalayan region for the treatment of different ailments. However, despite its traditional uses, it is not widely explored for its free radical scavenging abilities and other biological activities. Thus, the current study is aimed at exploring the free radical scavenging ability of S. heteromalla extracts, along with the isolation and evaluation of its compound through bioassay-guided purification. From different solvent fractions, an n-hexane extract of a whole plant is found to be most active; thus, it is processed for large-scale extraction and column chromatography. Further, the purification of an active fraction is performed using HPLC–DAD, which led to the isolation of an active peak, identified by GC/MS, as 2-ethylhexyl 2-cyano-3, 3-diphenylprop-2-enoate. This compound, commonly known as octocrylene, is widely recommended for UV-B filter, to be used in the cosmetic industry as photoprotection products. The presence of free radical scavenging activity enhances the sun protection factor of octocrylene. The present study presents the first report on the isolation of this compound from the family Asteraceae. The compound has good free radical scavenging activity and is widely used in the cosmetic industry as a sun protectant and is much less reported from botanical sources.

Effects of consumer products chemicals ingredients and their mixtures on the estrogen receptor/androgen receptor transcriptional activation

Unlike the environmental pollutants or industrial chemicals, the chemicals in consumer products may pose higher levels of risks, depending on how the chemicals are used in the products and how humans interact with the products. Recently, endocrine disrupting chemicals in cosmetics, personal care products, cleaners, sunscreens, and vinyl products were analytically quantified and many active chemicals including phthalates, parabens and bisphenols were detected. This indicates a wide range of exposures from common products. In this study, 35 chemicals known to be ingredients of consumer products were selected and screened for the transactivation of estrogen receptors and androgen receptors. From the results of individual chemicals, the activity of binary/ternary mixture prepared from the agonists for the ER transcription activity was measured, and compared to the predicted values obtained by the full logistic model. The measured and the predicted values were found to be very similar. This study may suggest that prediction of mixture activity by proper models would be one of the supportive tools for the risk assessment and sound regulation of chemical mixtures which have potential endocrine disrupting effects in consumer products.

Octocrylene exposure impairs mouse oocyte quality by inducing spindle defects and mitochondria dysfunction

One of organic ultraviolet (UV) filters, Octocrylene (OCL), is mainly used in various cosmetic products, which is being frequently detected in soil, sediment, aquatic systems and food chain. There is evidence confirmed the reproductive toxicity of OCL in Japanese medaka. However, less was known about the effects of OCL exposure on oocyte quality. Here, we investigated the impacts of OCL on mouse oocyte maturation and quality by exposing oocytes to OCL in vitro at concentrations of 8, 22, 30, 40 and 50nM. The results showed that OCL markedly reduced mouse oocyte germinal vesicle breakdown (GVBD) at 50nM and polar body extrusion (PBE) rates at 40 and 50nM. OCL exposure further disrupted spindle assembly and chromosome alignment, finally inducing aneuploid. Mitochondrial function was also damaged by OCL exposure, leading to ROS overproduction and apoptosis in oocytes. Moreover, OCL treatment impaired the distribution of cortical granules and sperm binding ability of oocytes. In summary, these data demonstrated that OCL could disturb the oocyte meiotic maturation and reduce oocyte quality.

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.

Criticisms in the Development of High-Protection and Broad-Spectrum “Natural/Organic” Certifiable Sunscreen

Attention to environmental issues has become increasingly important in recent years and also massively affects the cosmetics sector. In this context, sunscreens are questioned due to the proven or believed ecotoxicity of organic ultraviolet (UV) filters. This has pushed developers increasingly towards the use of inorganic filters, which can prove difficult to spread with low compliance. We faced the problem by proposing a rational approach based on the evaluation of the morphology of the inorganic material, as the real dimension does not often correspond to the characteristics declared by the producers because the material itself tends to aggregate. A combination of a specially selected inorganic filter is required to formulate Cosmetic Products with a Natural and Sustainable Connotation (CPCNS) standards.

MS imaging and absorption methods visualizing sun filter skin spatial distribution and penetration

Sunscreens must now be effective in protecting skin from ultraviolet, as well as visible/infrared radiation. Here, TriAsorB, a new broad-spectrum sun filter, was formulated with three other sunscreens and their distribution on human skin was studied using a standard penetration protocol and two novel mass spectrometry imaging techniques: atmospheric pressure matrix assisted laser desorption ionization (AP-MALDI) coupled to high resolution mass spectrometry and time of flight - secondary ion mass spectrometry (ToF-SIMS). The standard penetration protocol showed that sun filters absorption was very low, with most of the dose recovered at the surface (none entered the receptor fluid). Absorption was not increased in damaged skin. The results were confirmed by AP-MALDI and ToF-SIMS imaging of the spatial distribution of molecular species in cross-section samples of human skin. Each sun filter was detected on or in the stratum corneum, with a good homogenous coverage over the valleys and peaks of the skin, and correlated well with the distribution of endogenous biomarkers. In conclusion, conventional and novel imaging analysis methods showed that the sun filters remained mainly on the skin surface after topical application. Mass spectrometry imaging is a promising complementary approach to traditional skin penetration studies to visualize penetration of compounds.

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.

Bioaccumulation and trophic transfer of organic ultraviolet absorbents in the food web of a freshwater lake: Implications for risk estimation

Organic ultraviolet absorbents (UVAs) are increasingly reported in environmental matrices and organisms. However, available information on the bioaccumulation of UVAs in freshwater species is insufficient and their trophodynamics in lake food webs remain unknown. We measured the concentrations of twelve UVAs in the wild species from Lake Chaohu. Except for UV-320 not detected, the other UVAs were prevalent in the study species and their total concentrations were in the range of 5.44-131 ng/g dry weight, which were comparable to the concentrations reported in other waters. Compound and species-specific accumulations of UVAs in the organisms were observed. In the lake, the log-transformed concentrations of 4-methyl benzylidene camphor, octyl p-dimethylaminobenzoate, UV-326, and UV-327 related significantly to the trophic levels of species separately. The calculated trophic magnification factors (TMFs) of the four UVAs were 3.79, implying trophic magnification, and 0.18, 0.40 and 0.58, suggesting trophic dilution, respectively. These suggested that the magnification potential and the associated risks of individual UVAs in freshwater lake differed. To our knowledge, this is the first report of these TMFs in lake food webs. However, more investigation is needed to characterize their trophodynamic behaviors in lakes because food web characteristics likely affect trophic transfer of these chemicals.

Sunscreen lotions in the dermatological prescription: review of concepts and controversies

The skin is regularly exposed to several environmental aggressions, including solar radiation, whose biological effects can induce sunburn, dyschromia, skin aging and cancer. Among the photoprotection measures, sunscreens comprise a relevant part of the strategy aimed to prevent solar radiation damage and, for effective action, the patient must adhere to the product use and the latter, in turn, must follow technical parameters to promote adequate protection. This review article brings together the most current and relevant concepts about photoprotection for dermatological use, including the challenges for their formulation, the risks of certain photoprotective active substances for individual and environmental safety and the importance of stringency in determining the product efficacy, considering the regulatory aspects, highlighting relevant differences between Brazil and other countries. Thus, when assessing a sunscreen, not only the visual aspects and sensory perception will be immediately evaluated, but also the quality and suitability of the vehicle, the chemical composition of the formulation, the environmental risks, the photostability of the screening system, and the measurement of its protection spectrum. Technical knowledge of sunscreens can help dermatologists in this important role of educating patients about the best photoprotective strategies in each situation.

Vaccinium myrtillus L. extract associated with octocrylene, bisoctrizole and titanium dioxide: in vitro and in vivo tests to evaluate safety and efficacy

OBJECTIVE

The harmful effects induced by ultraviolet exposition and the significant increment in skin cancer diagnosis confirm the necessity to develop effective and safe sunscreens. Limited efficacy and cutaneous adverse reactions of traditional formulations drove the incorporation of natural extracts into multifunctional sunscreens. Vaccinium myrtillus L. extract (VME), that contains anthocyanins and flavonoids, is a potential candidate for such systems.

METHODS

Considering that, we performed in vitro and in vivo tests to evaluate the sun protection factor (SPF), photostability and safety of sunscreen samples containing VME.

RESULTS

As main results, the SPF was reduced in both in vitro and in vivo evaluation in the presence of VME, nonetheless, the samples were photostable and safe.

CONCLUSION

Further investigation is required to better understand the unexpected effects of VME over photoprotection, decreasing the SPF value. As a conclusion, even with interesting findings, we highlight the importance of case-by-case investigations to develop multifunctional bioactive sunscreens.

The Use of Calcium Phosphates in Cosmetics, State of the Art and Future Perspectives

Calcium phosphates (CaPs) belong to a class of biomimetic materials widely employed for medical applications thanks to their excellent properties, such as biodegradability, biocompatibility and osteoinductivity. The recent trend in the cosmetics field of substituting potentially hazardous materials with natural, safe, and sustainable ingredients for the health of consumers and for the environment, as well as the progress in the materials science of academics and chemical industries, has opened new perspectives in the use of CaPs in this field. While several reviews have been focused on the applications of CaP-based materials in medicine, this is the first attempt to catalogue the properties and use of CaPs in cosmetics. In this review a brief introduction on the chemical and physical characteristics of the main CaP phases is given, followed by an up-to-date report of their use in cosmetics through a large literature survey of research papers and patents. The application of CaPs as agents in oral care, skin care, hair care, and odor control has been selected and extensively discussed, highlighting the correlation between the chemical, physical and toxicological properties of the materials with their final applications. Finally, perspectives on the main challenges that should be addressed by the scientific community and cosmetics companies to widen the application of CaPs in cosmetics are given.

(+)-Usnic Acid as a Promising Candidate for a Safe and Stable Topical Photoprotective Agent

The study aimed to examine whether usnic acid—a lichen compound with UV-absorbing properties—can be considered as a prospective photoprotective agent in cosmetic products. Moreover, a comparison of two usnic acid enantiomers was performed to preselect the more effective compound. To meet this aim, an in vitro model was created, comprising the determination of skin-penetrating properties via skin-PAMPA assay, safety assessment to normal human skin cells (keratinocytes, melanocytes, fibroblasts), and examination of photostability and photoprotective properties. Both enantiomers revealed comparable good skin-penetrating properties. Left-handed usnic acid was slightly more toxic to keratinocytes (IC₅₀ 80.82 and 40.12 µg/mL, after 48 and 72 h, respectively) than its right-handed counterpart. The latter enantiomer, in a cosmetic formulation, was characterized by good photoprotective properties and photostability, comparable to the UV filter octocrylene. Perhaps most interestingly, (+)-usnic acid combined with octocrylene in one formulation revealed enhanced photoprotection and photostability. Thus, the strategy can be considered for the potential use of (+)-usnic acid as a UV filter in cosmetic products. Moreover, the proposed model may be useful for the evaluation of candidates for UV filters.

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.

The Role of Photoprotection in Optimizing the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with an estimated prevalence of 10-15% in children and 2-10% in adults. Clinically, there is notable phenotypic variability driven by a complex interaction between genetics, immune function, and the environment. Impairment of the skin barrier plays a significant role in the pathogenesis of AD. The apparent beneficial effect of sunlight in patients with atopic eczema is questioned due to its capacity to disrupt the skin barrier and generate free radicals that can damage proteins, lipids, and DNA. The sum of the external factors that an individual is exposed to throughout their lifetime is termed the exposome. Environmental factors such as sun exposure, temperature, and humidity contribute to both AD flares and regional prevalence variation. Literature on photoprotection in atopic dermatitis is very scarce. The use of adequate sunscreens in atopic dermatitis can ensure the level of photoprotection required to prevent skin photoaging and skin cancer and to mitigate skin barrier dysfunction, decrease inflammation, and neutralize facial redness. Herein we discuss and review the role of UV radiation and the exposome in the etiology of AD, as well as the role of adequate photoprotection.

A burning issue: The effect of organic ultraviolet filter exposure on the behaviour and physiology of Daphnia magna

Ultraviolet (UV) filters are compounds utilized in many manufacturing processes and personal care products such as sunscreen to protect against UV-radiation. These highly lipophilic compounds are emerging contaminants of concern in aquatic environments due to their previously observed potential to bioaccumulate and exert toxic effects in marine ecosystems. Currently, research into the toxic effects of UV filter contamination of freshwater ecosystems is lacking, thus the present study sought to model the effects of acute and chronic developmental exposures to UV filters avobenzone, oxybenzone and octocrylene as well as a mixture of these substances in the freshwater invertebrate, Daphnia magna, at environmentally realistic concentrations. Median 48-hour effect and lethal concentrations were determined to be in the low mg/L range, with the exception of octocrylene causing 50% immobilization near environmental concentrations. 48-hour acute developmental exposures proved to behaviourally impair daphnid phototactic response; however, recovery was observed following a 19-day post-exposure period. Although no physiological disruptions were detected in acutely exposed daphnids, delayed mortality was observed up to seven days post-exposure at 200 μg/L of avobenzone and octocrylene. 21-day chronic exposure to 7.5 μg/L octocrylene yielded complete mortality within 7 days, while sublethal chronic exposure to avobenzone increased Daphnia reproductive output and decreased metabolic rate. 2 μg/L oxybenzone induced a 25% increase in metabolic rate of adult daphnids, and otherwise caused no toxic effects at this dose. These data indicate that UV filters can exert toxic effects in freshwater invertebrates, therefore further study is required. It is clear that the most well-studied UV filter, oxybenzone, may not be the most toxic to Daphnia, as both avobenzone and octocrylene induced behavioural and physiological disruption at environmentally realistic concentrations.

[Power station sun and hormone factory skin : A current assessment of the importance of vitamin D metabolism during human evolution and strategies for UV prevention]

The sun is of great importance for human health. One important reason for this is the production of vitamin D, endorphins and many other hormones by the skin due to stimulation by sunlight. Insufficient access to sunlight increases the risk for vitamin D deficiency, a pandemic which would affect more than one billion people worldwide and under which ca. 60% of the population in Germany would suffer. The skin has a unique position in vitamin D metabolism as elementary steps for vitamin D production take place here and it is furthermore a target organ for actions of vitamin D. Due to the many positive effects of the sun, a healthy balance must be found between UV protection to shield against skin cancer but also ensuring sufficient vitamin D production. For regulation of this fragile balance between photoprotection and vitamin D production, which has accompanied mankind throughout evolution, sunscreens are an integral part of the modern lifestyle, although critical reports on possible risks for their use have recently become more frequent. This article discusses the current state of knowledge on the importance of vitamin D metabolism in human skin and the use of sun creams.