Sunscreens: Obtaining adequate photoprotection

Exposure to UV-B filter octylmethoxycinnamate and human health effects: Focus on endocrine disruptor actions

Human skin is the first line of photoprotection against UV radiation. However, despite having its defence mechanisms, the photoprotection that the skin exerts is not enough. To protect human skin, the inclusion of UV filters in the cosmetic industry has grown significantly as a photoprotection strategy. Octylmethoxycinnamate, also designated by octinoxate, or 2-ethylhexyl-4-methoxycinnamate (CAS number: 5466-77-3) is one of the most widely used UV-B filter in the cosmetic industry. The toxic effects of OMC have alarmed the public, but there is still no consensus in the scientific community about its use. This article aims to provide an overview of the UV filters' photoprotection, emphasizing the OMC and the possible negative effects it may have on the public health. Moreover, the current legislation will be addressed. In summary, the recommendations should be rethought to assess their risk-benefit, since the existing literature warns us to endocrine-disrupting effects of OMC. Further studies should be focus on the toxicity of OMC alone, in mixture and should consider its degradation products, to improve the knowledge of its risk assessment as EDC.

Skin Cancer Awareness and Knowledge About Sun Protection Practices in Solid Organ Transplant Recipients: Patient Survey Study

BACKGROUND

Adequate sun protection practices in chronically immunosuppressed patients can minimize the burden of the most common type of skin cancer in this population. In addition, early recognition of skin cancer by patients can lead to decreased morbidity, and possibly mortality from the disease. Nevertheless, there are significant gaps in the knowledge of sun protection measures and early recognition of skin cancer.

OBJECTIVE

The aim of this study is to determine the risk factors of solid organ transplant recipients (SOTRs) for developing skin cancer and their sun exposure education and behavior post-transplantation.

MATERIALS AND METHODS

This study evaluates the responses of 107 SOTRs on their outlooks and beliefs of sunscreen usage, skin cancer, and sun exposure knowledge.

RESULTS

Our study identified several significant risk factors for the development of actinic keratosis or keratinocyte carcinoma in SOTRs including history of sunburn before age 18, blue eyes, history of tanning bed use, performing monthly skin exams, ability to identify precancerous skin lesions, and history of previous skin examinations.

CONCLUSION

A patient-centered approach needs to be used to properly educate patients on effective ways to reduce excessive sun exposure. Regular skin examinations, and patients continued education are necessary components in reducing the burden of skin cancer in SOTRs.

Sun protection behaviors among children aged 6-18 years old, the role of socioeconomic factors: A cross-sectional study

Background and Aims

Evaluation of sun protection behavior and related factors in children aged between 6 and 18 years in Isfahan, Iran.

Methods

This cross-sectional study was conducted at outpatient pediatric clinics affiliated with Isfahan University of Medical Sciences, Isfahan, Iran during the summer of 2021. A checklist was designed, and the interviewer used that to gather the required information including children's demographic characteristics, families' socioeconomic data, and sun-protective behaviors in children.

Results

The mean ± standard deviation (SD) age of children was 10.54 ± 3.61. Among the study population, 63.7% of children were male. The most common skin phototypes were II and III (33.5% each). 83.8% of children used at least one method of sun protection (94.5% of girls, 77.6% of boys, p < 0.001). Wearing long-sleeved clothes was the most frequent UV-protection method (48%), while sunscreen application was the least prevalent method (28.1%). Sun protection behaviors were more frequent among urban children (86.7%, p = 0.009) and children with wealthy families (94%, p = 0.035). Sun protection methods were used by most of the children whose mothers applied sunscreen on a daily basis (90.2%, p = 0.002) and all of the children whose mothers held a master's degree or above (100%, p = 0.004).

Conclusion

Children's sun protection behavior is directly associated with demographic characteristics, families' socioeconomic level and maternal usage of sun protection measures. It is necessary to provide information and education about sun protection methods and the risks of excessive sun exposure to families and children, as well as facilitate their access to these.

Biomineralization: A new tool for developing eco-sustainable Ti-doped hydroxyapatite-based hybrid UV filters

It is well known that the prolonged exposure to UV radiation from sunlight can compromise human health and is particularly damaging to the skin, leading to sunburn, photo-aging and skin cancer. Sunscreen formulations containing UV-filters present a barrier against solar UV and help to mitigate the harmful effects however, concern about their safety for both human and environmental health is still a much-debated topic. EC regulations classify UV-filters depending on their chemical nature, particle size, and mechanism of action. Furthermore, it regulates their use in cosmetic products with specific limitations in terms of concentration (organic UV filters) and particle size and surface modification to reduce their photo-activity (mineral UV filters). The regulations have prompted researchers to identify new materials that show promise for use in sunscreens. In this work, biomimetic hybrid materials composed of titanium-doped hydroxyapatite (TiHA) grown on two different organic templates, derived from animal (gelatin - from pig skin) and vegetable (alginate - from algae) sources. These novel materials were developed and characterized to obtain sustainable UV-filters as a safer alternative for both human and ecosystem health. This 'biomineralization' process yielded TiHA nanoparticles that demonstrated high UV reflectance, low photoactivity, good biocompatibility and an aggregate morphology which prevents dermal penetration. The materials are safe for topical application and for the marine environment; moreover, they can protect organic sunscreen components from photodegradation and yield long-lasting protection.

Development and Characterization of Methyl-Anthranilate-Loaded Silver Nanoparticles: A Phytocosmetic Sunscreen Gel for UV Protection

Methyl anthranilate (MA) is a naturally derived compound commonly used in cosmetic products, such as skin care products, fine perfumes, etc. The goal of this research was to develop a UV-protective sunscreen gel using methyl-anthranilate-loaded silver nanoparticles (MA-AgNPs). The microwave approach was used to develop the MA-AgNPs, which were then optimized using Box-Behnken Design (BBD). Particle size (Y1) and absorbance (Y2) were chosen as the response variables, while AgNO₃ (X1), methyl anthranilate concentration (X2), and microwave power (X3) were chosen as the independent variables. Additionally, the prepared AgNPs were approximated for investigations on in vitro active ingredient release, dermatokinetics, and confocal laser scanning microscopy (CLSM). The study's findings showed that the optimal MA-loaded AgNPs formulation had a particle size, polydispersity index, zeta potential, and percentage entrapment efficiency (EE) of 200 nm, 0.296 mV, -25.34 mV, and 87.88%, respectively. The image from transmission electron microscopy (TEM) demonstrated the spherical shape of the nanoparticles. According to an in vitro investigation on active ingredient release, MA-AgNPs and MA suspension released the active ingredient at rates of 81.83% and 41.62%, respectively. The developed MA-AgNPs formulation was converted into a gel by using Carbopol 934 as a gelling agent. The spreadability and extrudability of MA-AgNPs gel were found to be 16.20 and 15.190, respectively, demonstrating that the gel may spread very easily across the skin's surface. The MA-AgNPs formulation demonstrated improved antioxidant activity in comparison to pure MA. The MA-AgNPs sunscreen gel formulation displayed non-Newtonian pseudoplastic behaviour, which is typical of skin-care products, and was found to be stable during the stability studies. The sun protection factor (SPF) value of MA-AgNPG was found to be 35.75. In contrast to the hydroalcoholic Rhodamine B solution (5.0 µm), the CLSM of rat skin treated with the Rhodamine B-loaded AgNPs formulation showed a deeper penetration of 35.0 µm, indicating the AgNPs formulation was able to pass the barrier and reach the skin's deeper layers for more efficient delivery of the active ingredient. This can help with skin conditions where deeper penetration is necessary for efficacy. Overall, the results indicated that the BBD-optimized MA-AgNPs provided some of the most important benefits over conventional MA formulations for the topical delivery of methyl anthranilate.

Experimental and Computational Analysis of Para-Hydroxy Methylcinnamate following Photoexcitation

Para-hydroxy methylcinnamate is part of the cinnamate family of molecules. Experimental and computational studies have suggested conflicting non-radiative decay routes after photoexcitation to its S₁(ππ*) state. One non-radiative decay route involves intersystem crossing mediated by an optically dark singlet state, whilst the other involves direct intersystem crossing to a triplet state. Furthermore, irrespective of the decay mechanism, the lifetime of the initially populated S₁(ππ*) state is yet to be accurately measured. In this study, we use time-resolved ion-yield and photoelectron spectroscopies to precisely determine the S₁(ππ*) lifetime for the s-cis conformer of para-hydroxy methylcinnamate, combined with time-dependent density functional theory to determine the major non-radiative decay route. We find the S₁(ππ*) state lifetime of s-cis para-hydroxy methylcinnamate to be ∼2.5 picoseconds, and the major non-radiative decay route to follow the [¹ππ*→¹nπ*→³ππ*→S₀] pathway. These results also concur with previous photodynamical studies on structurally similar molecules, such as para-coumaric acid and methylcinnamate.

Sunscreens effectiveness are not altered by concomitant use of moisturizing creams: An ultraviolet reflectance photography study

BACKGROUND

Sunscreens are widely used to protect the skin against the harmful effects of solar radiation. It is not known whether solar protection factor of a sunscreen is altered by the concomitant use of other cosmetic products.

OBJECTIVES

The aim of this study was to analyze changes in the protective effect of different commercial and ISO standards sunscreens with high SPF applied shortly before and after application of non-sunscreens galenic formulas type moisturizing creams.

METHODS

ISO 24444:2019 standard sunscreens, which claimed SPF 16 and 63, as well as 4 different claimed SPF 50 and 50+ commercial sunscreens were prepared and applied in different sequential order to the back of 25 volunteers and compared with different commercial moisturizing formulas. Ultraviolet (UV) reflectance photography followed by image analysis was used to compare untreated skin and skin treated with moisturizing creams alone and combined with sunscreens.

RESULTS

The UV reflectance analysis showed no significant changes of the skin color reflectance treated with moisturizing cream compared with untreated skin. Application of the sunscreen formulations were associated with a 35% - 70% decrease in color related to the in vivo expected SPF, indicating significant UV absorption for all sunscreen formulas. All standard and commercial sunscreens showed no significant differences in UV reflection color level when combined with the different moisturizing creams applied before or after the sunscreen.

CONCLUSIONS

Effectiveness of low- and high-protection sunscreens were not altered by the concomitant use of a moisturizing creams applied shortly before and after the sunscreens.

Comparative sensory and instrumental analyses and principal components of commercial sunscreens

BACKGROUND

The initial contact of consumers when choosing sunscreens is through the trademark, packaging, perfume, and tactile feeling of the product, outlining the popular practice of sensory science.

AIMS

To describe the sensory and physical-mechanical profile of commercial sunscreens through sensory and instrumental analyses related to principal component analysis (PCA).

METHODS

Seven commercial sunscreens available on the Brazilian market and with a solar protection factor (SPF) of 30 were evaluated. Physical-mechanical profiling (rheological and textural analyses) was conducted by a trained panel, followed by sensory profile characterization and descriptive analysis. The results were assessed using the Spearman correlation coefficient and PCA.

RESULTS

The correlation or lack thereof of the instrumental parameters with most of the sensory aspects was demonstrated using the Spearman coefficient. PCA enabled us to identify the nature of the dissimilarities among the samples.

CONCLUSIONS

The obtained results highlight the importance of descriptive sensory analysis in the research and development of sunscreens, evidencing the significance of precisely informing the products' formulation in order to be chosen by the consumer.

Visible light. Part II: Photoprotection against visible and ultraviolet light

Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.

Silver Nanoparticles Protect Skin from Ultraviolet B-Induced Damage in Mice

Ultraviolet (UV) radiation from sunlight has various adverse effects; thus, UV blockage is recommended for preventing sunburn. Common sunscreen ingredients, such as nanosized titanium dioxide and zinc oxide, offer effective protection and enhance cosmetic appearance; however, health concerns have been raised regarding their photocatalytic activity, which generates reactive oxygen species under UV illumination. Silver nanoparticles (AgNPs) are known as safe materials for use in a wide spectrum of biomedical applications. In vitro studies have revealed that AgNPs may have a protective effect against UV irradiation, but the effects in animal studies remain unclear. The present study demonstrated that AgNPs effectively protect against UVB-induced skin damage both in cell cultures and mouse models. These results suggested that AgNPs are feasible and safe as sunscreen ingredients for protection against UVB-induced skin damage.

A decade of sun protection in Australian early-childhood services: analysis of cross-sectional and repeated-measures data

Limiting ultraviolet radiation exposure during early childhood can significantly reduce the risk of developing skin cancer, making early childhood a critical time for sun protection strategies. This study aimed to measure sun protection practices utilized in Australian early-childhood services over the past decade and evaluate the impact of Cancer Council Australia's SunSmart Early-Childhood Program. Results are presented from cross-sectional and repeated-measures survey data, completed by directors or other staff at randomly sampled early-childhood services in 2008, 2013 and 2018 (N�=�3243). Most sun protection practices were used by a significantly greater proportion of services in 2018 relative to earlier years, such as requiring the use of sunscreen (98.4%), and sun-protective hats (99.7%) and clothing (88.8%). However, only a small and declining proportion of services (16.3%-22.4%) required the use of specific items of sun-protective clothing. SunSmart program members reported enacting significantly more sun protection practices compared to non-members, while new members showed an increase in the use of those practices relative to services whose status did not change (d�=�0.48). The results demonstrate improvements in sun protection in Australian early-childhood settings, and highlight the benefits and limitations of the SunSmart program.

Application of Factorial Design and Rheology to the Development of Photoprotective Formulations

A sunscreen should form a stable and homogeneous film over the skin surface, which can improve its photoprotective activity and avoid adverse effects. For this purpose, the definition of the appropriate vehicle is of fundamental importance since emulsifying agents are known to directly influence the stability, sensorial properties and surface tension of sunscreens, modulating their film-forming performance. In this context, the objective of the present study was to systematically develop formulations with UVB/UVA protection and evaluate the effect of wax concentration on the rheological behaviour. A 2-level full factorial design was applied for the development of four formulations. Two categorical factors were evaluated, glyceryl stearate plus PEG-75 stearate (Wax 1) and methyl glucose sesquistearate (Wax 2). Rheological behaviour was determined in triplicate and rheograms were analysed using the Ostwald model. Rheological parameters were correlated by the Spearman rank correlation test and effects were evaluated by Pareto chart and surface response methodology (SRM). It was possible to identify the pseudoplastic and thixotropic behaviour of all formulations exhibiting a thinning effect on higher shear stress. Factorial analysis showed that both waxes significantly influenced consistency and thixotropic behaviour. The effect of Wax 2 concentration in thixotropy was positive and of higher magnitude and a synergistic effect was also observed. Spearman correlation coefficient of consistency index and apparent viscosity was significantly strong and positive. Finally, factorial analysis allowed the determination of the effects of waxes on the rheological parameters of the formulations. A quantitative relationship between wax concentration and significant responses was established, permitting the prediction of desirable rheological properties for improved sunscreen efficacy.

Antioxidants as stabilizers of UV filters: an example for the UV-B filter octylmethoxycinnamate

Background

Sunlight is one of the main harmful exogenous factors that induce the reactive oxygen species formation. The human skin is the first line of photoprotection against harmful exogenous factors, such as UV radiations. The topical application of sunscreens, containing UV-B filters, is widely used to protect against UV-induced damage. Octylmethoxycinnamate is the world’s most widely used UV-B filter in sunscreens. However, recent studies have demonstrated that this substance is an endocrine disruptor compound and with potential to damage DNA. Thus, the safety of this organic filter is a current concern for human health, and it was urgent to develop new photoprotective strategies. In this sense, due to the potential to neutralize the UV-induced free radicals, the use of antioxidants as UV filter stabilizers presented as a novel promising strategy.

Research

The purpose of this review was to assess the use of antioxidants as stabilizers for UV-B filter octylmethoxycinnamate. For this, we discuss the chemical and physical characteristics of UV-B filter octylmethoxycinnamate, emphasizing the stability, photostability, and reactivity of this UV filter. The use of antioxidants in sunscreens will also be addressed, from a perspective of the main characteristics that allowed their use in sunscreen formulations. Then, the concomitant use of both was described from a historical and physical chemical perspective, always emphasizing the advantages and disadvantages of this association.

Conclusions

The combination of antioxidants with UV-B filter octylmethoxycinnamate in appropriated formulations represents a viable strategy to protect the human skin against UV-induced damage.

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.

Photoprotection of ultraviolet-B filters: Updated review of endocrine disrupting properties

The Ultraviolet (UV) radiation is emitted by the sun and is part of the electromagnetic spectrum. There are three types of UV rays (UV-A, UV-B and UV-C), however only UV-A and UV-B have biologic effects in humans, with UV-B radiation being primarily responsible for these effects. Among the measures of photoprotection advised by the health authorities, the topical application of sunscreens (containing UV-B filters) is the preferred worldwide. Currently, octylmethoxycinnamate (OMC) is the most commonly used UV-B filter in sunscreens. Their application has proven to be effective in preventing burns, but its efficiency against melanoma continues under intense controversy. Studies have shown that OMC behaves like an endocrine disruptor, altering the normal functioning of organisms. However, few studies have evaluated their multiple hormonal activities. Some studies suggest that the OMC exerts an estrogenic, anti-androgenic, anti-progestenic and anti-thyroid activity. But, through what mechanisms? In humans, few studies were performed, and some questions remain unclear. Thus, the purpose of this review is to present the multiple hormonal activities established for the OMC, making a critical analysis and relationship between the effects in cells, animals and humans.

Sun protection for preventing basal cell and squamous cell skin cancers

BACKGROUND

'Keratinocyte cancer' is now the preferred term for the most commonly identified skin cancers basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), which were previously commonly categorised as non-melanoma skin cancers (NMSC). Keratinocyte cancer (KC) represents about 95% of malignant skin tumours. Lifestyle changes have led to increased exposure to the sun, which has, in turn, led to a significant increase of new cases of KC, with a worldwide annual incidence of between 3% and 8%. The successful use of preventive measures could mean a significant reduction in the resources used by health systems, compared with the high cost of the treatment of these conditions. At present, there is no information about the quality of the evidence for the use of these sun protection strategies with an assessment of their benefits and risks.

OBJECTIVES

To assess the effects of sun protection strategies (i.e. sunscreen and barrier methods) for preventing keratinocyte cancer (that is, basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) of the skin) in the general population.

SEARCH METHODS

We searched the following databases up to May 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trial registries and the bibliographies of included studies for further references to relevant trials.

SELECTION CRITERIA

We included randomised controlled clinical trials (RCTs) of preventive strategies for keratinocyte cancer, such as physical barriers and sunscreens, in the general population (children and adults), which may provide information about benefits and adverse events related to the use of solar protection measures. We did not include trials focused on educational strategies to prevent KC or preventive strategies in high-risk groups. Our prespecified primary outcomes were BCC or cSCC confirmed clinically or by histopathology at any follow-up and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for eligibility using Early Review Organizing Software (EROS). Similarly, two review authors independently used predesigned data collection forms to extract information from the original study reports about the participants, methods of randomisation, blinding, comparisons of interest, number of participants originally randomised by arm, follow-up losses, and outcomes, and they assessed the risk of bias. We resolved any disagreement by consulting a third author and contacted trial investigators of identified trials to obtain additional information. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included one RCT (factorial design) that randomised 1621 participants.This study compared the daily application of sunscreen compared with discretionary use of sunscreen, with or without beta-carotene administration, in the general population. The study was undertaken in Australia; 55.2% of participants had fair skin, and they were monitored for 4.5 years for new cases of BCC or cSCC assessed by histopathology. We found this study to be at low risk of bias for domains such as allocation, blinding, and incomplete outcome data. However, we found multiple unclear risks related to other biases, including an unclear assessment of possible interactions between the effects of the different interventions evaluated (that is, sunscreen and beta-carotene). We found no difference in terms of the number of participants developing BCC (n = 1621; risk ratio (RR) 1.03, 95% confidence interval (CI) 0.74 to 1.43) or cSCC (n = 1621; RR 0.88, 95% CI 0.50 to 1.54) when comparing daily application of sunscreen with discretionary use, even when analyses were restricted to groups without beta-carotene supplementation. This evidence was of low quality, which means that there is some certainty that future studies may alter our confidence in this evidence.We reported adverse events in a narrative way and included skin irritation or contact allergy.We identified no studies that evaluated other sun protection measures, such as the use of sun-protective clothing, sunglasses, or hats, or seeking the shade when outdoors.

AUTHORS' CONCLUSIONS

In this review, we assessed the effect of solar protection in preventing the occurrence of new cases of keratinocyte cancer. We only found one study that was suitable for inclusion. This was a study of sunscreens, so we were unable to assess any other forms of sun protection. The study addressed our prespecified primary outcomes, but not most of our secondary outcomes. We were unable to demonstrate from the available evidence whether sunscreen was effective for the prevention of basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC).Our certainty in the evidence was low because there was a lack of histopathological confirmation of BCC or cSCC in a significant percentage of cases. Amongst other sources of bias, it was not clear whether the study authors had assessed any interaction effects between the sunscreen and beta-carotene interventions. We think that further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

Nanodiamonds protect skin from ultraviolet B-induced damage in mice

BACKGROUND

Solar ultraviolet (UV) radiation causes various deleterious effects, and UV blockage is recommended for avoiding sunburn. Nanosized titanium dioxide and zinc oxide offer effective protection and enhance cosmetic appearance but entail health concerns regarding their photocatalytic activity, which generates reactive oxygen species. These concerns are absent in nanodiamonds (NDs). Among the UV wavelengths in sunlight, UVB irradiation primarily threatens human health.

RESULTS

The efficacy and safety of NDs in UVB protection were evaluated using cell cultures and mouse models. We determined that 2 mg/cm(2) of NDs efficiently reduced over 95% of UVB radiation. Direct UVB exposure caused cell death of cultured keratinocyte, fibroblasts and skin damage in mice. By contrast, ND-shielding significantly protected the aforementioned pathogenic alterations in both cell cultures and mouse models.

CONCLUSIONS

NDs are feasible and safe materials for preventing UVB-induced skin damage.

Research on the immunosuppressive activity of ingredients contained in sunscreens

The immunosuppressive properties of Benzophenone-4, an UV-filter and three ingredients, Allantoin, Bisabolol and Enoxolon used in sunscreen formulation, previously characterized as anti-inflammatory compounds, are studied. The results of this study demonstrate that four tested molecules have effects on DCs and T cells which are the most important cells of the immune system. The impact is also visible on keratinocyte cells which are in the direct contact with skin sunscreens. Each ingredient should be used with caution at reduced doses or even removed from some cosmetic preparations, such as sunscreens.