Organic UV Filters Research Articles

Sun-protection factor of zinc-oxide sunscreens: SPFin vitro too low compared to SPFin vivo—a brief review

Sunscreens are mainly characterized by their sun-protection factor (SPF), which is measured according to the in vivo gold standard ISO 24444. Although the SPF concept is simple, SPF values are difficult to measure, due to the rather high variability caused by the complex interaction of light and skin. For half a century, there have been attempts to correlate the costly and ethically controversial in vivo procedure with a non-invasive (in vitro) method. After decades of development, alternative non-invasive SPF methods are expected to become available as ISO standards in early 2025. In particular, sunscreen manufacturers who use zinc oxide (ZnO) in higher concentrations (conc.) (10–25%) in their formulations, are concerned that these new in vitro methods would not confirm the SPF-values on their labels that have been determined in vivo, according to ISO 24444. This brief review reveals that sunscreen formulations with high conc. of ZnO often yield SPFin vitro values that are lower than the SPFin vivo values. This can be explained by the fact that in vitro methods have been developed for conventional emulsions products with organic UV filters, but not for highly concentrated ZnO-alone sunscreens. Fortunately, there seems to be a fix for this problem. There is a difference in density between ordinary emulsions with organic filters (density of the residual oil phase ~ 1.0 g/ml) and highly concentrated ZnO-alone formulations (~ 1.3–1.7 g/ml). As the application of current standards is weight-based, this makes the film on the PMMA plate much thinner, which is likely to lead to lower SPFin vitro values. Preliminary experiments show that using the same volume on the PMMA plates instead of the same weight as organic UV filters gives a much better correlation between in vitro and in vivo SPF results. A recent evaluation of three samples of highly concentrated ZnO sunscreens by the Dutch NVWA seems to confirm these findings. Further experimental evidence is required to fully understand this phenomenon and to adapt the in vitro method for higher conc. ZnO formulations accordingly.

Embryonal exposure to 4-methylbenzylidene camphor induces reproduction impairment in adult zebrafish (Danio rerio)

This study investigated how early exposure to xenobiotics can lead to disease in adulthood, which is challenging for toxicologists. We employed a ‘cradle to grave’ approach using zebrafish (Danio rerio) embryos exposed to 4-methylbenzylidene camphor (4-MBC), a commonly used organic UV filter. Molecular docking and simulation studies confirmed the predictive toxicity and stable interaction of 4-MBC with androgen and estrogen receptors, with binding energies of −9.28 and −9.01 kcal/mol, respectively. Exposure to 4-MBC at 5, 50, and 500 μg/L concentrations resulted in significantly altered transcriptional and translational responses of ar, esr1, and vtg1 genes in embryos at 120 h post-fertilization (hpf). The exposure induced a non-monotonic dose-response pattern (NMDR), a characteristic feature of endocrine-disrupting chemicals. Additionally, a significant decrease in fertilization was observed in adults. Although fecundity was not affected in inter- and intra-breeding performances, developmental deformities were observed in F1 progenies with impaired survival at 10 days post-fertilization. The findings of this study show that embryonic exposure to 4-MBC is likely to induce reproductive and transgenerational toxicity in D. rerio and exhibit endocrine disruption in aquatic non-target organisms. This work is the first to elucidate the low-level long-term effects of 4-MBC from the embryonic stage to adulthood.

Electrochemical oxidation of UV filters: A first-principles molecular dynamics study.

A theoretical model is proposed to study the oxidation mechanisms of the organic UV filters BP3 and BP4 during electrochemical water treatment utilizing Car-Parrinello molecular dynamics. Factors such as the amount of solvent to be included and how to design the system with the least possible intervention are discussed. The stages of the proposed model consist of the optimization of the geometries by density functional theory methods, the equilibration of the structure immersed in a water box, the inclusion of the reactive species, and the analysis of the reaction energies of each reaction pathway. The ab-initio molecular dynamics simulations lead to several products, and some trends can be identified, in accordance with the well-known reactivity rules of organic chemistry. The products proposed in this work are intermediates in longer oxidative pathways.

Thyroid, neurodevelopmental, and kidney toxicities of common organic UV filters in embryo-larval zebrafish (Danio rerio), and their potential links

Organic UV filters (OUVFs) have been commonly used in sunscreen and many consumer products. Following dermal application, these compounds can enter circulation and may cause systemic effects in humans. In the present study, we chose four OUVFs frequently detected in the environment, i.e., avobenzone (AVB), benzophenone-3 (BP-3), octocrylene (OC), and octyl methoxycinnamate (OMC), and evaluated their thyroid, neurodevelopmental, and kidney toxicities. For this purpose, zebrafish embryos (<4 h post fertilization, hpf) were exposed to sublethal concentrations of AVB, BP-3, OC, or OMC until 120 hpf. Exposure to all OUVFs decreased thyroid hormone (TH) levels, probably by enhanced metabolism and excretion of THs (ugt1ab and/or sult1 st5) in the larval fish. Exposure to the OUVFs also induced hypoactivities and/or anxiety-like behaviors: Regulatory changes of mbp, gfap, c-fos, syn2a, sty1a, and stxbp1b genes, support the changes in normal neurobehavior of the larval fish. Moreover, the OUVFs exposure caused increased proteinuria in the fish, along with transcriptional changes of wt1, nephrin, podocin, and cdh17 genes, which could explain the observed reduction in kidney functions. Principal component analysis (PCA) implied the potential interplay of THs with neurogenesis, or podocyte differentiation of the larval fish. Toxicological consequences of altered TH homeostasis, neurobehavior, and kidney function at the early life stage warrant further investigations not only in humans but also in aquatic ecosystems.

Interplay of UV-filter pollution and temperature rise scenarios on Mytilus galloprovincialis health: Unveiling sperm quality and adult physiology, biochemistry, and histology insights

Addressing the impacts of emerging contaminants within the context of climate change is crucial for understanding ecosystem health decline. Among these, the organic UV-filters 4-methylbenzylidenecamphor (4-MBC) and benzophenone-3 (BP-3) are widely used in cosmetics and personal care products. Their unique physico-chemical properties, along with their growing commercialization and consumption, have made them ubiquitous in aquatic environments through both direct and indirect releases, raising significant concerns about their potential threats to inhabiting biota. Additionally, increasing surface water temperatures exacerbate ecological risks, making it imperative to understand the implications for non-target species at different biological levels. This study investigated the short- and long-term effects of UV-filters 4-MBC or BP-3, at ecologically relevant concentrations, combined with current and predicted warming scenarios, on the performance and male reproductive health of Mytilus galloprovincialis mussel populations. Using biomarkers across sub-cellular, cellular, tissue, and individual levels, the study revealed significant physiological and biochemical impairments in both sperm cells and adults exposed to UV-filters. Temperature emerged as the primary driver influencing mussel responses and modulating the impacts of 4-MBC/BP-3, emphasizing their sensitivity to temperatures outside the optimal range and interactive effects between stressors. Specifically, sperm motility declined with increasing UV-filter concentrations, while temperature alone influenced ROS production, leading to compromised mitochondrial activity and DNA damage in the presence of combined stressors, indicative of potential reproductive impairments. Adults exhibited high UV-filter bioconcentration potential in whole tissues, compromised physiological status, morphophysiological changes in digestive glands, oxidative stress, and alterations in metabolic capacity, antioxidant defences, and biotransformation mechanisms, correlating with UV-filter exposure and temperature increase. Among the UV-filters tested, 4-MBC was the most detrimental, especially when combined with warming. Overall, this study underscores the vulnerability of M. galloprovincialis to cumulative stressors and highlights the importance of employing a multi-biomarker approach to assess and mitigate the impacts of stressors on coastal ecosystems.

Predicting the acute aquatic toxicity of organic UV filters used in cosmetic formulations

Background and purpose: Organic UV filters are commonly used in sunscreen and cosmetic formulations to protect against harmful UV radiation. However, concerns have emerged over their potential toxic effects on aquatic organisms. This study aims to investigate the acute aquatic toxicity of 13 organic UV filters and determine whether phospholipid binding, measured through biomimetic chromatographic methods, is a better predictor of toxicity than the traditionally used octanol-water partition coefficient (log P). Experimental approach: The chromatographic retention of the 13 UV filters was measured on an immobilized artificial membrane (IAM) stationary phase to assess phospholipid binding. These measurements were then applied to previously established predictive models, originally developed for pharmaceutical compounds, to estimate acute aquatic toxicity endpoints of 48-hour LC50 for fish and the 48-hour EC50 (immobilization) for Daphnia magna. Key results: Phospholipid binding was found to be a more reliable predictor of the acute aquatic toxicity of UV filters compared to log P. The toxicity was primarily driven by lipophilicity and charge, with negatively charged compounds exhibiting lower toxicity. Conclusion: The study demonstrates that phospholipid binding is a better descriptor of UV filter toxicity than log P, providing a more accurate method for predicting the environmental risk of these compounds. This insight can guide the development of more environmentally friendly sunscreens by reducing the use of highly lipophilic and positively charged compounds, thus lowering their aquatic toxicity.

Would Rutin be a Feasible Strategy for Environmental-Friendly Photoprotective Samples? A Review from Stability to Skin Permeability and Efficacy in Sunscreen Systems

Rutin, a flavonoid found in various plants, has gained attention for its potential applications in the cosmetic industry due to its antioxidant, anti-inflammatory, and potential photoprotective properties. Our review explored the use of rutin (rutoside, 3-O-rutinoside-quercetin) in cosmetics/dermocosmetics, focusing on its physicochemical properties and stability, cutaneous permeability, and efficacy in sunscreen systems, involving in vitro tests and the current state of clinical trials. Rutin’s ability to scavenge free radicals, prevent peroxidation, and reduce vascular fragility makes this flavonoid a promising ingredient for photoprotection. Studies have shown that rutin can enhance the sun protection factor (SPF) of sunscreen formulations, especially when combined with organic UV filters. The encapsulation of rutin in nanostructures has also been investigated to improve its applicability. Overall, rutin shows potential as a safe and effective ingredient in cosmetics/dermocosmetics, offering protection against the harmful effects of UV radiation and oxidative stress on the skin, as well as being a feasible strategy for developing environmentally friendly multifunctional sunscreens.

New metabolites of 2-ethylhexyl salicylate in human urine after simulated real-life dermal sunscreen application

2-Ethylhexyl salicylate (EHS) is an organic UV filter which is used in sunscreen and other personal care products. The dermal uptake of EHS was studied in several dermal-exposure experiments. This paper aims to coherently assess urine samples after dermal exposure for the biomarkers EHS, 5OH-EHS, 5oxo-EHS, and 5cx-EPS as well as further biomarkers of interest, specifically 4OH-EHS, 4oxo-EHS, 2OH-EHS, and 6OH-EHS, for the first time. Samples from 18 participants of a pre-existing dermal exposure study under real-life conditions were reassessed using a comprehensive LC-MS/MS method. EHS accounts for 34 % of the cumulative excretion of all analytes within 24 h after exposure, followed by 5OH-EHS (19 %), 5cx-EPS (18 %), 4OH-EHS (15 %) and 5oxo-EHS (11 %). Further metabolites were only quantified in minor amounts. EHS as the most prominent excretion parameter in this study demonstrates the missing first-pass effect after dermal absorption. Furthermore, the applied novel comprehensive analytical procedure revealed oxidation at the ω (5cx-EPS, 6OH-EHS), ω-1 (5OH-EHS, 5oxo-EHS), and ω-2 positions (4OH-EHS, 4oxo-EHS) in the main chain of the ethylhexyl group as well as oxidation in the side chain (2OH-EHS). The presented data are of high relevance for a reliable toxicological risk assessment of dermal exposure to EHS.

Distribution and accumulation of UV filters (UVFs) and conservation status of Posidonia oceanica seagrass meadows in a prominent Mediterranean coastal tourist hub

This study investigates the presence and impact of UV filters in Posidonia oceanica meadows in Formentera, a Mediterranean tourist hotspot. It highlights the distribution of inorganic (TiO2 and ZnO) and organic UV filters (UVFs) in different environmental matrices, their accumulation in seagrass tissues and their impact on the seagrass health.In the overlying and canopy waters of P. oceanica, Zn concentrations surpassed Ti, with three organic UVFs (benzophenone-3 [BP-3], avobenzone and homosalate [HMS]) consistently detected. Ti concentrations were generally higher than Zn in rhizosphere sediments, along with recurrent presence of octocrylene, HMS, 2-ethylhexyl methoxycinnamate (EHMC), and 4-methylbenzylidene camphor (4-MBC). Maximum Zn concentrations were found in canopy waters (3052.9 ng L−1). Both Ti and Zn were found in all P. oceanica tissues and leaf epiphytes across all study sites. Additional UVFs like octocrylene, avobenzone, and BP-8 were also detected in P. oceanica tissues and epiphytes. Elevated levels of octocrylene in leaf epiphytes (2112.1 ng g−1 dw) and avobenzone in leaves (364.2 ng g−1 dw) and leaf epiphytes (199.6 ng g−1 dw) were observed in the Port of La Savina, the island's main entry port. Octocrylene concentrations (up to 2575 ng g−1 dw) in rhizosphere sediments near sewage discharge points exceeded reported maxima, highlighting wastewater treatment plants as significant sources of organic UVFs. Correlational analyses suggested that the accumulation of octocrylene, avobenzone, and BP-3 negatively impacted P. oceanica's conservation status, affecting global density, density at 100 % cover, and leaf morphometry. Positive correlations were observed between leaf polyphenols (antioxidants) and concentrations of avobenzone, benzophenone-8 (BP-8), and BP-3, indicating potential oxidative stress induced by UVFs in P. oceanica.Our study underscores the pervasive presence of UV filters in P. oceanica habitats, with implications for seagrass health and conservation, especially in areas of high tourism and sewage discharge.

Evaluation of Single and Binary Mixture Toxicity of Organic UV-Filters Using H295R Cells

Evaluation of Single and Binary Mixture Toxicity of Organic UV-Filters Using H295R Cells

Ionic liquids-based nanoemulsion for assisted by ultrasound liquid–liquid microextraction of UV-filters in water samples

Organic UV filters can contaminate various bodies of water such as streams, rivers, and seas, and as such, they have been identified as emerging contaminants of relevance in aquatic ecosystems. Therefore, the detection and determination of these compounds at low concentrations from an environmentally friendly perspective are necessary. In this work, an ionic liquids based nanoemulsion for the ultrasound assisted liquid–liquid microextraction (ILs-NE/US-LLME) of benzophenone-3, octocrylene, octisalate and octinoxate in different water bodies was reached. The material was based on a mixture of the ionic liquids 1,3-didecyl-2-methylimidazolium chloride and 1-butyl-3-methylimidazolium hexafluorophosphate, and the surfactant Triton X-100. The microextraction process was assisted by ultrasound and was performed using 475 µL of extractant solvent and 10.0 mL of sample, and an optimal preconcentration factor of 100 was achieved. The detection was performed by HPLC-UV in less than 5 min for all analytes. Low detection limits (lower than 2.0 µg L−1) and an optimal precision (RSD lower than 6.7 %) were obtained for the four UV filters. Different water samples (pool, stream, river, sea and a simulated sample) were analyzed and satisfactory recovery values were obtained in all cases (82–119 %). The method was fast (15 min−1) and it presented an optimal value of greenness (0.50) according to the AGREE metric. The extractant material was easily synthesized using a minimum amount of materials. The chromatographic procedure for separation and detection of the analytes was simple and fast. Moreover, the method was more environmentally friendly compared to previous work reported in the literature.

New Insight into the Degradation of Sunscreen Agents in Water Treatment Using UV-Driven Advanced Oxidation Processes

This study evaluates, for the first time, the effects of UV/PMS and UV/H2O2/PMS processes on the degradation of sunscreen agents in synthetic and natural water matrices and compares their effectiveness with the more conventional UV/H2O2. Investigations were conducted using a mixture of organic UV filters containing 4-methylbenzylidene camphor (4-MBC) and 2-ethylhexyl-4-methoxycinnamate. Among the investigated UV-driven AOPs, UV/PMS/H2O2 was the most effective in synthetic water, while in natural water, the highest degradation rate was observed during the degradation of EHMC by UV/PMS. The degradation of UV filters in the UV/PMS system was promoted by sulfate radical (68% of the degradation), with hydroxyl radical contributing approximately 32%, while both radical species contributed approximately equally to the degradation in the UV/H2O2/PMS system. The Vibrio fischeri assay showed an increase in inhibition (up to 70%) at specific stages of UV/H2O2 treatment when applied to natural water, which further decreased to 30%, along with an increase in UV fluence and progressive degradation. The Pseudomonas putida test recorded minor toxicity (&lt;15%) after treatments. Magnetic biochar utilized in conjunction with UV-driven AOPs exhibited superior performance in eliminating residual contaminants, providing an efficient and sustainable approach to mitigate sunscreen agents in water treatment.

Sunscreen use during recreational activities on a French Atlantic beach: release of UV filters at sea and influence of air temperature.

Organic UV filters are emerging contaminants in personal care products such as sunscreens. The toxicity of numerous of these UV filter compounds has been demonstrated in several marine taxa. However, whilst the biological impact has already been largely demonstrated, the anthropogenic drivers leading to UV filter contamination still need to be identified. In this work, a survey was conducted on a site of the French Atlantic Coast (i) to describe beachgoers' behaviours (sunscreen use and beach frequentation), (ii) provide an estimation of the UV filters released at sea and (iii) highlight the effect of air temperature on these behaviours and on the release of UV filters. In parallel with these estimations of the UV filters released at sea, in situ chemical measurements were performed. By comparing the results of both approaches, this interdisciplinary work provides an insight of how the observations of beachgoers' behaviour modulations and attendance level fluctuations could be used to prevent UV filter contaminations and ultimately manage the ecotoxicological risk.

Inorganic UV filter-based sunscreens labelled as eco-friendly threaten sea urchin populations

Although the negative effects of inorganic UV filters have been documented on several marine organisms, sunscreen products containing such filters are available in the market and proposed as eco-friendly substitutes for harmful, and already banned, organic UV filters (e.g. octinoxate and oxybenzone). In the present study, we investigated the effects of four sunscreen products, labelled by cosmetic companies as “eco-friendly”, on the early developmental stages of the sea urchin Paracentrotus lividus, a keystone species occurring in vulnerable coastal habitats. Among sunscreens tested, those containing ZnO and TiO2 or their mix caused severe impacts on sea urchin embryos. We show that inorganic UV filters were incorporated by larvae during their development and, despite the activation of defence strategies (e.g. phagocytosis by coelomocytes), generated anomalies such as skeletal malformations and tissue necrosis. Conversely, the sunscreen product containing only new-generation organic UV filters (e.g. methylene bis-benzotriazolyl tetramethyl, ethylhexyl triazone, butylphenol diethylamino hydroxybenzoyl hexyl benzoate) did not affect sea urchins, thus resulting actually eco-compatible. Our findings expand information on the impact of inorganic UV filters on marine life, corroborate the need to improve the eco-friendliness assessment of sunscreen products and warn of the risk of bioaccumulation and potential biomagnification of inorganic UV filters along the marine food chain.

Dangers of Oxybenzone in Sunscreens on Coral Reefs: Proposed Policy Approaches

Sunscreen was developed to combat the harmful effects of skin exposure to ultraviolet radiation, but organic UV filters like oxybenzone pose a threat to coral reefs by promoting bleaching incidents, damaging coral DNA, and interfering with coral larvae. Oxybenzone has also been found to cause a wide range of reproductive and developmental harm within other marine organisms, like fish and invertebrates. While there are alternative sunscreens that are less detrimental to coral such as mineral-based products, toxic oxybenzone-based sunscreens are still popular among cosmetic companies and consumers. Scientific findings in the past decade have demonstrated a connection between high concentrations of chemical UV filters and the destruction of marine ecosystems. This knowledge has prompted some governments in coastal regions to pass legislation aiming to limit the use of sunscreens containing these chemicals. These regulations provide beneficial case studies that can be used to develop further effective policies to federally ban these products in the United States. The jurisdictions of Hawaii, the US Virgin Islands, and Key West are model examples of successful implementation of such laws domestically. Based on efforts from such coastal communities, our suggested best practices to eliminate the threat posed by harmful sunscreens are to promote alternative sunscreen use, to define ‘reef-safe’ within the Federal Trade Commission’s Green Guides, and to impose a nationwide ban on oxybenzone. These recommendations provide a comprehensive plan to protect the United States’ fragile marine ecosystems.

Organic UV filters: Occurrence, risks and (anti-)progestogenic activities in samples from the Czech aquatic environment and their bioaccumulation in fish

The occurrence, environmental risks and contribution of organic UV filters to detected (anti-)progestogenic activities were examined in samples of wastewater treatment plant influents and effluents, various surface waters and fish from the Czech Republic. Of the 20 targeted UV filters, 15 were detected in the WWTP influent samples, 11 in the effluents, and 13 in the surface water samples. Benzophenone-3, benzophenone-4, and phenyl benzimidazole sulfonic acid (PBSA) were found in all water samples. Octocrylene, UV-327 and 4-methylbenzylidene camphor exceeded the risk quotient of 1 at some sites. In the anti-progestogenic CALUX assay, 10 out of the 20 targeted UV filters were active. Anti-progestogenic activities reaching up to 7.7 ng/L, 3.8 ng/L, and 4.5 ng/L mifepristone equivalents were detected in influents, effluents, and surface waters, respectively. UV filters were responsible for up to 37 % of anti-progestogenic activities in influents. Anti-progestogenic activities were also measured in fish tissues from the control pond and Podroužek (pond with the highest number of detected UV filters) and ranged from 2.2 to 9.5 and 1.9 to 8.6 ng/g dw mifepristone equivalents, respectively. However, only benzophenone was found in fish, but it does not display anti-progestogenic activity and thus could not explain the observed activities.

NLC-Based Sunscreen Formulations with Optimized Proportion of Encapsulated and Free Filters Exhibit Enhanced UVA and UVB Photoprotection.

The topical use of sunscreens is recommended for avoiding the damaging effects of UV radiation. However, improvements are still needed in the existing products to enhance their photoprotection effectiveness and safety. This involves minimizing the use of chemical UV filters while providing enhanced and prolonged photoprotection. This work investigated novel sunscreen formulations and their UV protection effects by encapsulating Uvinul® A, Tinosorb® S, and Uvinul® T150 into nanostructured lipid carriers (NLCs) based on bacuri butter and raspberry seed oil. First, the impact of critical formulation and process parameters on NLCs' particle size was evaluated using a 22 Face Centered Central Composite Design. Then, formulations were evaluated in terms of critical quality factors, in vitro skin permeation, and in vitro and in vivo photoprotection activities. The developed NLCs-containing formulations exhibited appropriate size (122-135 nm), PdI (<0.3), encapsulation efficiency (>90%), and drug content (>80%), which were preserved for at least 90 days under different stability conditions. Moreover, these NLCs-based formulations had equivalent skin permeation to emulsion-based controls, and the addition of NLCs into sunscreen cream bases in the optimum proportion of 20% (w/w) resulted in enhanced UVA and UVB photoprotection levels, despite a 10% reduction in the total filters content. Altogether, these results describe the application of nanoencapsulated organic UV filters in innovative sunscreen formulations to achieve superior photoprotection and cosmeceutical properties.

Zeofilters for potentially innovative sunscreen products: formulation, stability and spectroscopic studies

Exposure to both UVA and UVB radiation from the sun stands as the primary cause of skin cancers, contributing to the escalating yearly count of diagnosed cases. Sunscreen products, (i.e. organic and inorganic UV filters) have become ubiquitous in personal-care products, packaging, plastics, dyes, and many other sectors. Ideal UV filters should be photostable and dissipate the absorbed energy efficiently. However, most organic UV filters are photolabile upon protracted UV exposure, leading to the formation of photoproducts of unknown toxicity for human health and environment. The chemical environment surrounding UV filters may strongly affect their behaviour: the interaction with other components of sunscreen formulations may enhance their degradation. Particularly, the interaction between photochemically incompatible ingredients must be avoided. Therefore, much effort has been invested in developing more effective and safe sunscreens.Our team recently focused on the preparation and characterization of hybrid UVfs obtained by the encapsulation of organic UV filters into various zeolites differing for topology. The zeolite most efficient for the encapsulation of organic UV filters, in term of stability and efficiency in radiation filtration, resulted to be LTL zeolite. Here, hybrid materials realized after the encapsulation of octinoxate (OMC) and avobenzone (AVO) in LTL zeolite were tested in terms of skin permeation profiles, cytotoxicity and photostability once the materials are dispersed in cream formulations, so to mimicking the real condition of use.The results show that the hybrids were successfully incorporated into oil-in-water emulsions and the skin permeation tests displayed a very low UV filter permeation through pig skin and no UV filter accumulation in dermis layer.The photostability of the hybrid-based emulsions were compared with that of emulsions containing a mixture of bare OMC and AVO, highlighting a reduced decrease in UV screening efficiency upon irradiation for the samples containing the hybrid materials with respect to the free filters. This evidence confirms that the encapsulation in the zeolite frameworks prevents some of the photodegradation reactions. The result of this paper highlights that zeolite encapsulation is increasingly establishing as a viable way to stabilize UV filters and other photoactive molecules.

Single-polyp metabolomics for coral health assessment

Coral reef ecosystems supported by environmentally sensitive reef-building corals face serious threats from human activities. Our understanding of these reef threats is hampered by the lack of sufficiently sensitive coral environmental impact assessment systems. In this study, we established a platform for metabolomic analysis at the single-coral-polyp level using state-of-the-art mass spectrometry (probe electrospray ionization/tandem mass spectrometry; PESI/MS/MS) capable of fine-scale analysis. We analyzed the impact of the organic UV filter, benzophenone (BP), which has a negative impact on corals. We also analyzed ammonium and nitrate samples, which affect the environmental sensitivity of coral-zooxanthella (Symbiodiniaceae) holobionts, to provide new insights into coral biology with a focus on metabolites. The method established in this study breaks new ground by combining PESI/MS/MS with a technique for coral polyps that can control the presence or absence of zooxanthellae in corals, enabling functions of zooxanthellae to be assessed on a polyp-by-polyp basis for the first time. This system will clarify biological mechanisms of corals and will become an important model system for environmental impact assessment using marine organisms.

Identification, Organic Synthesis, and Sensitive Analysis of a cis-Homosalate-Specific Exposure Biomarker.

Homosalate (HMS) is an organic UV filter used in sunscreens and personal care products. Despite its widespread use and detection in environmental matrices, little is known regarding its exposure in humans. HMS is used as a mixture of cis- and trans-isomers, and we recently revealed major differences in human toxicokinetics, indicating the need to consider these isomers separately in exposure and risk assessments. In the course of these previous investigations of human HMS toxicokinetics, we identified two trans-HMS-specific and one cis-HMS-specific biomarker candidates. However, the latter lacks sensitivity due to only low amounts excreted in urine, prompting the search for another cis-HMS-specific biomarker. Our toxicokinetic investigations revealed a total of five isomers of HMS carboxylic acid metabolites (HMS-CA). Of these, only one was specifically formed from cis-HMS (HMS-CA 5), but its full identity in terms of constitution and configuration had, so far, not been elucidated. Here, we describe the synthesis of three HMS-CA isomers, of which the isomer (1R,3S,5S)/(1S,3R,5R)-3-((2-hydroxybenzoyl)oxy)-1,5-dimethylcyclohexane-1-carboxylic acid turned out to be HMS-CA 5. Taken together with two previously synthesized HMS-CA isomers, we were able to identify the constitution and configuration of all five HMS-CA isomers observed in human metabolism. We integrated the newly identified cis-HMS-specific metabolite HMS-CA 5 into our previously published human biomonitoring LC-MS/MS method. Intra- and interday precisions had coefficients of variation below 2% and 5%, respectively, and the mean relative recovery was 96%. The limit of quantification in urine was 0.02 μg L-1, enabling the quantification of HMS-CA 5 in urine samples for at least 96 h after sunscreen application. The extended method thus enables the sensitive and separate monitoring of cis- and trans-HMS in future human biomonitoring studies for exposure and risk assessment.