Photoprotective Efficacy Research Articles

The effect of on-site application density on the UV protection efficacy of sunscreens.

Sun protection factor (SPF) and UVA protection factor (UVAPF) are performance indicators consumers recognize for UV protective cosmetics such as sunscreens. However, on-site application density affects actual UV protection, despite these indicators. To understand actual UV protection better, a more reliable manner is needed to verify application density for further discussion of photoprotection efficacy regarding public health. To estimate the UV protective efficacy of sunscreen in actual use based on the application density of UV protective cosmetics and the analysis of UV protective effect modulated by application density. The subjects applied the SPF-labeled sunscreens as usual. We measured the application amount and area including any amount on their hands to calculate the average application density on the face. Also, sunscreens were applied at densities of 0.5, 1.0, and 2.0mg/cm2 . The SPF values were measured at each application site to evaluate the effect of application density on photoprotection efficacy. We established a method of measuring application density utilizing three-dimensional photograph analysis. The median application density of the sunscreen applied in actual use was 1.33mg/cm2 . The measured SPF values decreased in association with the decreased application density of sunscreens. Based on the estimate assuming the first-order correlation, the SPF value required to get the protective effect equivalent to a sunscreen with SPF 15, 30, or 50 at 2mg/cm2 was calculated to be 23.8, 47.5, and 79.2, respectively, with the application density of 1.33mg/cm2 . We demonstrated a reasonable procedure for estimating the photoprotection efficacy of sunscreens on the face. A suggestion was made to consider the application density for further discussion of photoprotection among consumers, especially for the long term with respect to public health.

Phenylene Bis-Diphenyltriazine (TriAsorB), a new sunfilter protecting the skin against both UVB + UVA and blue light radiations.

Sunlight induces actinic keratosis, skin cancers and photoaging. Photoprotection is thus a major issue in public health to prevent the harmful effects of solar ultraviolet (UV) radiations. Recent data have shown that the visible (VIS) and infrared (IR) radiations can lead to skin damage by oxidative stress, suggesting that a balanced protection across the entire spectrum of sunlight is necessary to prevent cutaneous alterations. In this context, we developed a new generation of sunfilter called Phenylene Bis-Diphenyltriazine or TriAsorB (CAS N°55514-22-2). The aim of the present study was to assess the photoprotective efficacy of TriAsorB from UV to IR light. Spectrophotometric assays were performed to measure absorption and reflectance of TriAsorB in the different spectral ranges of sunlight: UV, VIS including blue light or high energy visible (HEV) and IR. DNA damage was evaluated using reconstructed human epidermis (RHE): 8-hydroxy-2'-deoxyguanosine (8OHdG) in response to HEV exposure, pyrimidine dimers (CPDs) and (6-4) photoproducts following solar-simulated radiation (SSR). TriAsorB is a broad spectrum UVB + UVA filter including long UVA. Interestingly, it also absorbs VIS radiations, especially in the HEV region. These radiations are also reflected. Protection in the IR spectral range is weak. Furthermore, the sunfilter specifically protects the skin against the oxidative lesions 8OHdG induced by HEV and prevents SSR-induced DNA damage. Thus, TriAsorB is an innovative sunfilter that might be used in sun care products for skin photoprotection from UV to VIS radiations. Finally, it prevents sunlight genotoxicity and protected the skin against solar radiations, especially blue light.

Study of the influence of alcohol on the photostability of four UV filters.

Spray formulations are currently under development in the field of topical photoprotection. Such forms are characterized by their high fluidity, a property that is obtained by the presence of alcohol in the formula. The purpose of this work was to study the influence of ethanol in sunscreens on the photoprotective efficacy as well as the photostability of UV filters. The filters tested were octyl methoxycinnamate (OMC), PEG-25 PABA, octyl salicylate and butyl methoxydibenzoylmethane (BMDBM) at their maximum concentration authorized by European regulations and in the presence of increasing amounts of alcohol, up to 15% (w/w). The effect of the presence of alcohol on the efficacy of the filters and their photostability varies depending on the molecule considered. Alcohol has no effect on octyl salicylate, either on its efficacy or its photostability. However, filter stabilization is seen for BMDBM and PEG-25 PABA. Although these differences are significant, they are not great enough to justify large-scale use of ethanol in sunscreen products due to some of its properties, such as flammability.

Plants growing in Colombia as sources of active ingredients for sunscreens

Introduction Plants can be sources of photoprotective/antigenotoxic compounds that prevent cellular mutations involved in skin cancer and aging by regulating UV-induced mutability. Purpose The study was aimed at investigating the sunscreen properties of plants growing in Colombia. Materials and Methods Ultraviolet (UV) radiation-absorption capability of different plant extracts was examined. In vitro photoprotection efficacies were evaluated using in vitro indices such as sun protection factor (SPFin vitro) and critical wavelength (λc). Pearson correlation analysis was used to examine the relationship between SPFin vitro and complementary UVB- antigenotoxicity estimates (%GI) based on SOS Chromotest database. The cytotoxicity in human fibroblasts was studied using the trypan blue exclusion assay. Major compounds of promising plant extracts were determined by gas chromatography coupled to mass spectrometry (GC/MS). Results We showed that plant extracts have sunscreen properties against UVB, whereas broad-spectrum radiation protection efficacy was poor. SPFin vitro and %GI were correlated (R = 0.71, p < 0.0001) for the plant extracts under study. Three extracts obtained from Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides species resulted to possess high protection efficacy and relatively low cytotoxicity in human fibroblasts. These plant extracts contained major compounds such as α-pinene, trans-β-caryophyllene, γ-muurolene, γ-cadinene and caryophyllene oxide in A. Satureioides extract, trans-β-caryophyllene, caryophyllene oxide, squalene and α-amyrin in C. pellia extract, and p-cymene, carvacrol, trans-β-caryophyllene and pinocembrin in L. origanoides extract. Conclusions Plants growing in Colombia contain compounds which ca be useful for potential sunscreens. SPFin vitro and %GI estimates were correlated, but %GI estimates were more sensitive detecting activity at lower plant extract concentrations. Our results supported the need to use DNA damage detection assays as a complement to photoprotection efficacy measurement.

Rutina como fotoestabilizadora de protetores solares de amplo espectro / Routine as photostabilizer for broad spectrum sunscreens

The combination of butyl methoxydibenzoylmethane (BMBM) and octyl methoxycinnamate (EHMC) is widely used in pharmaceutical formulations but may exhibit alteration in spectral absorption following exposure to UV radiation. The addition of natural substances in sunscreen formulations has been explored regarding photoprotective efficacy. The main objective of this research was to evaluate the potential of rutin as a photostabilizer substance of EHMC and BMBM. The samples were evaluated before and after exposure to UV radiation to in vitro photoprotection and molecular interactions by 1H NMR, DSC, TG and qualitative analysis of the suppression of singlet energy state. The addition of rutin in the formulations containing BMBM and EHMC promoted an increase in the preservation of in vitro SPF of 53.9% to 65.8 (0.1% rutin ) and 70.8 % (1.0% rutin ). The DSC and TG curves of rutin showed interaction between the flavonoid and filters. The trans/cis ratio for EHMC improved from 5.5 ± 0.1 to 12.6 ± 0.4 with rutin addition. The suppression of the singlet state indicated that one of the mechanisms involved in the photostabilization is suppression of singlet excited state. These results can contribute to the development of broad-spectrum sunscreens formulations with increased safety and efficacy.

Prodigiosin Production and Photoprotective/Antigenotoxic Properties in Serratia marcescens Indigenous Strains from Eastern Cordillera of Colombia.

Serratia marcescens is a bacterial species that produces an antibacterial pigment (Prodigiosin) showing a wide adaptive response to environmental stresses. The study aimed to investigate Prodigiosin production in S. marcescens wild-type strains, as well as its relation to photoprotection and antigenotoxicity against UVB. Prodigiosin yield was spectrophotometrically assayed in extracts of bacterial strains grown in different culture media. In vitro photoprotection efficacy was evaluated using the invitro indices sun protection factor (SPFinvitro ) and critical wavelength (λc). The percentage of UVB antigenotoxicity estimates (%GI) in the SOS Chromotest was also evaluated. Correlation analysis was used to examine the relationship between Prodigiosin yield, SPFinvitro , %GI estimates and environmental traits (altitude, temperature, rainfall and solar irradiance). Prodigiosin yield in S. marcescens strains varied depending on culture media used for its growth, and it was correlated with environmental variables such as temperature and solar irradiance. SPFinvitro estimates were well correlated with Prodigiosin concentration and %GI values in the bacterial strains being studied. UVB photoprotective efficacy of the extracts obtained from S. marcescens strains depends on the strain's Prodigiosin yield and its antigenotoxic potential. The extracts with Prodigiosin yield higher than ~17 μg mL-1 could be used as sources of sunscreen ingredients.

Photoprotective activity of geopropolis produced by Melipona subnitida (Apidae, Meliponinae) in the semiarid of the Brazilian Northeast

Although geopropolis has been the subject of many chemical and pharmacological studies, there are few studies investigating the photoprotective activity of formulations containing propolis. Thus, we investigated in vivo the photoprotective efficacy of the cream containing geopropolis extract by macroscopic and histological evaluation of the skin of Wistar rats subjected to ultraviolet radiation (UVB). We also evaluated the chemical composition of hydroethanolic extract using the HPLC-DADESI-MS/MS technique, as well as antioxidant activity by the photocolorimetric method of free radical DPPH (2.2-diphenyl-1-picrylhydrazine) and cytotoxic activity by the in vitro MTT quantitative method [brometo de 3- (4.5dimetiltiazol-2-il)-2.5-difeniltetrazolio]. The extract had a varied chemical composition, 29 different phenolic compounds being detected, distributed between phenols and flavonoids, the latter being represented by chalcones, flavones and flavonols. The highest percentages of DPPH inhibition e o baixo valor de IC50 indicaram que o extrato apresentou alta atividade antioxidante. The hydroethanolic extract did not exert cytotoxic effects since high percentages of viability of L929 fibroblasts were observed after incubation for 72 hours at different concentrations of the extract. On skin submitted to cream application containing of geopropolis extract and the irradiation with UVB did not occur macroscopic and histological lesions. Thus, we concluded that the cream containing of geopropolis extract produced by Melipona subnitida was able to protect the skin from lesions induced by UVB irradiation, thus demonstrating photoprotective effect.

The real UVB photoprotective efficacy of vegetable oils: in vitro and in vivo studies.

Some vegetable oils are currently being promoted as a safe alternative to commercial sunscreens. The true UVB photoprotective efficacy of 14 virgin vegetable oils and the suitability of the dilution method for determining their SPF value were evaluated. Oils and standard sunscreens were investigated in vitro by the Mansur's method in Slovakia and in vivo by the ISO method in the Czech Republic. SPF values in vitro (0.1; 0.0; 0.4; 0.2 and 0.2) and in vivo (2.5; 1.2; 2.6; 2.6; and 2.8) of the five most promoted oils (from carrot seed, coconut, raspberry seed, rosehip seed, and wheat germ) were significantly lower than the values reported in the controversial studies. We have shown that the overestimated SPF values of these oils were determined by authors who did not strictly follow Mansur's original methodology. The other eight vegetable oils also provide no or negligible SPF values. Only the in vitro SPF value of 11.2 tamanu oil is worth mentioning, probably due to high proportion of calophyllolides. In vitro and in vivo SPF ratios from 1.14 to 0.94 obtained by two methods in two laboratories for six commercial sunscreen oils used as controls confirm the correctness of performing the Mansur's method in this study. However, this dilution method has proven to be fundamentally flawed in determining the SPF value of substances with such negligible photoprotection as most vegetable oils can provide. An SPF value of less than 1, which can be determined by this Mansur's method, is physiologically impossible and meaningless.

Determining the photostability of avobenzone in sunscreen formulation models using ultrafast spectroscopy.

Avobenzone is an ultraviolet (UV) filter that is often included in sunscreen formulations despite its lack of photostability. Its inclusion is necessary due to few existing alternatives for photoprotection in the UVA region (320-400 nm). To better understand and predict the photostability of avobenzone, ultrafast transient electronic absorption spectroscopy (TEAS) has been used to study the effects of solvent (including emollients), concentration and skin surface temperature on its excited-state relaxation mechanism, following photoexcitation with UVA radiation (∼350 nm). Subtle differences between the excited-state lifetimes were found between the systems, but the TEAS spectral features were qualitatively the same for all solution and temperature combinations. Alongside TEAS measurements, UV filter/emollient blends containing avobenzone were irradiated using simulated solar light and their degradation tracked using steady-state UV-visible spectroscopy. Sun protection factor (SPF) and UVA protection factor (UVA-PF) assessments were also carried out on representative oil phases (higher concentration blends), which could be used to formulate oil-in-water sunscreens. It was found that there was an apparent concentration dependence on the long-term photoprotective efficacy of these mixtures, which could be linked to the ultrafast photodynamics by the presence of a ground-state bleach offset. This combination of techniques shows potential for correlating long-term behaviours (minutes to hours) of avobenzone with its ultrafast photophysics (femtoseconds to nanoseconds), bridging the gap between fundamental photophysics/photochemistry and commercial sunscreen design.

Safety and Photoprotective Efficacy of a Sunscreen System Based on Grape Pomace (Vitis vinifera L.) Phenolics from Winemaking.

In winemaking, a large amount of grape pomace is produced that is rich in polyphenolics and highly beneficial for human health, as phenols are useful for skin ultraviolet (UV) protection. In this investigation, we evaluated the safety and clinical efficacy of a sunscreen system containing a grape pomace extract from Vitis vinifera L. as a bioactive ingredient. The recovery of phenolics in the waste was performed by percolation. Nine emulsions were developed using a factorial design and two were evaluated clinically: Formulation E, containing only UV filters (butylmethoxydibenzoyl methane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA), and F, with the extract at 10.0% w/w + UV filters. The antioxidant activity was determined by the DPPH assay and the in vitro efficacy was established by sun protection factor (SPF) measurements (Labsphere UV-2000S). Clinical tests were performed to determine safety (human repeated insult patch test) and to confirm efficacy (photoprotective effectiveness in participants). The results showed a synergistic effect between the sunscreen system and the extract on UVB protection and antioxidant activity. Both samples were considered safe. Formulation F was 20.59% more efficient in protecting skin against UVB radiation, taking approximately 21% more time to induce erythema compared to the extract-free sample.

Demonstration of the dangerous nature of 'homemade' sunscreen recipes.

Following a growing mistrust in a certain number of ingredients used by the cosmetic industry, it has become popular in recent years for consumers to make their own products at home. This trend now touches on all areas of the industry, but is especially found in the hygiene sector, with shampoos and toothpaste, and the care sector, with moisturizers and sunscreen, products. The objective of this study is to analyze sunscreen recipes found on the Internet and to assess their level of photoprotective efficacy. Fifteen Internet recipes were chosen, and then, the products were made in the laboratory following the protocols described. Using an in vitro method, the following efficacy indicators were determined for the preparations made: the Sun Protection Factor (SPF), the Production Factor in the UVA domain (PF-UVA), and the critical wavelength (λc ). Three of the 15 recipes studied do not contain any sunscreen and therefore constitute a major risk for users in case of exposure to the sun. The other 12 cannot be considered as sun protection products since all of them have an SPF under 6, the threshold value required in Europe. The recipes that we collected on the Internet are very dangerous since some of them have no photoprotective effect whatsoever and most of them do not ensure a sufficient level of photoprotection for the persons using them.

Conservation of ultrafast photoprotective mechanisms with increasing molecular complexity in sinapoyl malate derivatives.

Sinapoyl malate is a natural plant sunscreen molecule which protects leaves from harmful ultraviolet radiation. Here, the ultrafast dynamics of three sinapoyl malate derivatives, sinapoyl L‐dimethyl malate, sinapoyl L‐diethyl malate and sinapoyl L‐di‐t‐butyl malate, have been studied using transient electronic absorption spectroscopy, in a dioxane and methanol solvent environment to investigate how well preserved these dynamics remain with increasing molecular complexity. In all cases it was found that, upon photoexcitation, deactivation occurs via a trans‐cis isomerisation pathway within ∼20–30 ps. This cis‐photoproduct, formed during photodeactivation, is stable and longed‐lived for all molecules in both solvents. The incredible levels of conservation of the isomerisation pathway with increased molecular complexity demonstrate the efficacy of these molecules as ultraviolet photoprotectors, even in strongly perturbing solvents. As such, we suggest these molecules might be well‐suited for augmentations to further improve their photoprotective efficacy or chemical compatibility with other components of sunscreen mixtures, whilst conserving their underlying photodynamic properties.

634 Photoprotective efficacy of a new sunscreen formulation SPF50+ against chronic UV-induced skin damage in an ex vivo human skin model

Introduction: The prevalence of skin cancer has increased in last decade and is mostly due to chronic sunlight exposure. Therefore, it is important to prevent sun-induced skin damage by using photoprotection strategies. Objective: To assess the photoprotective efficacy of an innovative emulsion containing specific sunfilters combination to protect the skin against UV-induced lesions. Materials and Methods: An ex vivo human skin model was developed to mimic chronic exposure of solar-simulated radiation (CSSR).

Is the Botryococcus braunii Dry Biomass an Adjuvant for Anti-UVB Topical Formulations?

Several topical products have been developed to avoid the harmful effects from ultraviolet (UV) radiation, such as sunscreens. Research for actives from natural sources is increasing due to the fact that chemical filters could induce adverse events. The microalgae Botryococcus braunii has potential interest in cosmetic applications. Specialized literature reported that B. braunii aqueous extract induced a reduction in skin dehydration and collagen production and promoted antioxidant activity. This research aimed to produce B. braunii biomass and to investigate its contribution regarding photoprotection. Formulations containing B. braunii dry biomass, with or without UV filters into vehicles composed of an emulsifying polymer or a self-emulsifying base, were evaluated in vitro by means of photoprotective activity and photostability. B. braunii dry biomass did not provide adequate photoprotection efficacy; however, it was observed that the self-emulsifying base promoted better sun protection factor (SPF) in comparison with the emulsifying polymer.

Dyed hair photoprotection efficacy of a quercetin-loaded cationic nanoemulsion

Dyed hair photoprotection efficacy of a quercetin-loaded cationic nanoemulsion

Influence of Shea (Butyrospermum parkii) butter, TiO2 and ethylhexyl methoxycinnamate on physical parameters and in vitro photoprotective efficacy.

The development of photoprotective lipsticks containing natural bioactive compounds is a relevant current strategy to increase sun protection factor (SPF) value and lower the concentration of chemical UV filters, known for promoting sensitivity reactions. Twelve photoprotective lipsticks were developed by Design of Experiment (DOE) and characterized to verify the influence of Shea butter (Butyrospermum parkii), titanium dioxide (TiO2 ), and ethylhexyl methoxycinnamate (EHM) on physical parameters and in vitro photoprotective efficacy. The influence of Shea butter, TiO2, and EHM was evaluated by several parameters, such as melting point, colorimetry, thermal analysis by DSC, texture analysis, and sunscreen activity estimated in vitro. The construction of prediction models was possible for the following responses: maximum force by the cantilever test at 25 and 45°C; maximum distance by hardness test at 25°C; slope value at 25 and 45°C by the cantilever test; and UVA/UVB ratio and in vitro SPF. TiO2 and EHM contributed to changes on the in vitro SPF value; however, unexpectedly, Shea butter had no influence on this efficacy parameter. The assay allowed us to observe the influence of the variables in the analysis and to develop a response prediction model for some of the parameters assessed.

Prospective Evaluation of the Efficacy of a Food Supplement in Increasing Photoprotection and Improving Selective Markers Related to Skin Photo-Ageing.

IntroductionSkin exposure to ultraviolet radiation (UVR) can cause oxidative stress, particularly in the absence of adequate protective measures or in individuals with a sensitive skin type. Most commonly, protection from UVR entails the use of topical sunscreens. Sunscreens, however, have various limitations. The objective of this study was to evaluate the efficacy and tolerability of an oral food supplement containing a combination of actives with mainly antioxidative properties (vitamins A, C, D3, E, selenium, lycopene, lutein, as well as green tea, polypodium and grape extracts) in the context of photoprotection.MethodsPhotoprotective efficacy was assessed in a 12-week-long, open, prospective and monocentric clinical study with 30 subjects (27 women and 3 men) having a Fitzpatrick skin type I-III and manifesting clinical ageing signs. The study included several visits (14, 28, 56, and 84 days after starting supplement intake), in which photoprotection was evaluated by the measurement of the minimal erythema dose (MED), while the antioxidant capacity of the skin was assessed through ferric reducing antioxidant power (FRAP) and malondialdehyde (MDA) assays. Additionally, several skin parameters (including radiance, elasticity, and moisture) were evaluated. Product evaluation was performed throughout the length of the study by means of a self-assessment questionnaire, and safety was monitored through a self-recording of all observed adverse reactions.ResultsThe MED levels increased significantly compared to baseline throughout the study visits, reaching an increase of + 8.1% at T84, p < 0.001. FRAP results also indicated a significant increase in the antioxidant capacity of the skin compared to baseline (+ 22.7% at T84, p < 0.001), while the MDA assay showed a significant decrease in MDA concentration compared to baseline (− 6.4% at T84, p < 0.001) which, in line with the FRAP results, indicated enhanced antioxidative protection of the skin. All assessed skin parameters, including radiance (+ 36.1% at T84, p < 0.001), gross elasticity (+ 13.2% at T84, p < 0.001), net elasticity (+ 28.0% at T84, p < 0.001), and moisture (+ 13.8% at T84, p < 0.001) were also significantly improved. The product was well tolerated as no adverse events were attributed by the investigators to the use of the product. Additionally, the global score obtained from the self-assessment questionnaires provided overwhelmingly positive feedback from the study subjects.ConclusionsThe food supplement evaluated in this study was effective and well-tolerated by the subjects, demonstrating a beneficial effect in terms of photoprotection, enhancing the antioxidative status of the skin and improving general skin condition.Trial RegistrationRetrospectively registered 3rd October 2019, ISRCTN18121679.Electronic supplementary materialThe online version of this article (10.1007/s13555-019-00345-y) contains supplementary material, which is available to authorized users.

The Synergistic Behavior of Antioxidant Phenolic Compounds Obtained from Winemaking Waste's Valorization, Increased the Efficacy of a Sunscreen System.

Grape pomace retains polyphenols in the peels and in the seeds after winemaking, which is indicative of the high valorization potential of this industrial waste. There is strong evidence that phenolics are robust antioxidants and confer photoprotection; thus, it is rational to apply these active compounds from winemaking waste to sunscreens, in order to increase UV protection. Despite the importance of this class of cosmetics to public health, more efficacious strategies are still needed to overcome the problems caused by the photoinstability of some UV filters. The hydroethanolic extract of Vitis vinifera L. grapes was obtained by percolation and then lyophilized. Six formulations were developed: Type I—cosmetic base and UV filters; Type II—cosmetic base and extract; and Type III—cosmetic base, extract and UV filters. Each formulation was prepared in the pHs 5 and 7. The antioxidant activities of the samples were measured by DPPH• and expressed in Trolox® equivalents (TE), and their photostability and in vitro sun protection factor (SPF) were analyzed by diffuse reflectance spectrophotometry. The anti-radical efficiencies observed in the formulations with grape extract were: (II) 590.12 ± 0.01 μmol TE g−1 at pH 5 and 424.51 ± 0.32 μmol TE g−1 at pH 7; (III) 550.88 ± 0.00 μmol TE g−1 at pH 5 and 429.66 ± 0.10 μmol TE g−1, at pH 7, demonstrating that the UV filters, butylmethoxydibenzoyl methane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl 4-aminobenzoic acid had no influence on this effect. The photoprotective efficacy and the photostability of formulation III containing the extract and UV filters at pH 5 suggested that a synergism between the active molecules provided an 81% increase in SPF. Additionally, this was the only sample that maintained a broad spectrum of protection after irradiation. These results confirmed that the grape pomace extract has multifunctional potential for cosmetic use, mainly in sunscreens, granting them superior performance.

Using ordered mesoporous silica SBA-15 to limit cutaneous penetration and transdermal permeation of organic UV filters.

Avobenzone (AVO), oxybenzone (OXY), and octyl methoxycinnamate (OMC), are widely used UV filters. The aim of this study was to investigate the effect of incorporation in mesoporous silica (SBA-15) on their cutaneous deposition and permeation. Stick formulations containing "free" and "incorporated" UV filters (SF1 and SF2, respectively) were prepared and characterized with respect to their physicochemical, thermal, and functional properties. Cutaneous delivery experiments using porcine skin with quantification by UHPLC-MS/MS, demonstrated that skin deposition of AVO and OXY after application of SF2 for 6 and 12 h was significantly lower than that from SF1 at each time-point (Student t-test, p < 0.05): e.g. OXY permeation across the skin was 30-, 12- and 1.5-fold lower after 6, 12 and 24 h, respectively, following application of SF2. Cutaneous biodistribution profiles of AVO and OXY to 800 µm evidenced a significant decrease in the amounts in the viable epidermis and dermis. In contrast, deposition of the more lipophilic OMC was not significantly different (p ˃ 0.05). In vitro photoprotective efficacy results demonstrated that adsorption/entrapment of UV filters enhanced the sun protection factor by 94%. In conclusion, SBA-15, an innovative mesoporous material, increased photoprotection by UV filters while reducing their cutaneous penetration and transdermal permeation.

Photoprotective and Antigenotoxic Effects of the Flavonoids Apigenin, Naringenin and Pinocembrin.

This work evaluated the photoprotective and antigenotoxic effects against ultraviolet B (UVB) radiation of flavonoid compounds apigenin, naringenin and pinocembrin. The photoprotective efficacy of these compounds was estimated using in vitro photoprotection indices, and the antigenotoxicity against UVB radiation was evaluated using the SOS chromotest and an enzymatic (proteinase K/T4 endonuclease V enzyme) comet assay in UV-treated Escherichia coli and human (HEK-293) cells, respectively. Naringenin and pinocembrin showed maximum UV-absorption peak in UVC and UVB zones, while apigenin showed UV-absorption capability from UVC to UVA range. These compounds acted as UV filters reducing UV-induced genotoxicity, both in bacteria and in human cells. The enzymatic comet assay resulted highly sensitive for detection of UVB-induced DNA damage in HEK-293 cells. In this work, the photoprotective potential of these flavonoids was widely discussed.