Non-sunscreen photoprotection: antioxidants add value to a sunscreen

Renewing the potential of rice crop residues as value-added products in the cosmetics industry

Purpose of this study is to explore the extraction of potentially valuable cosmetic ingredients from rice crop residues, aiming to mitigate their environmental impact.

Methods

We employed AOAC methods to analyze the fat, protein, ash, fiber, soluble, and insoluble carbohydrate content in these residues. To identify sugars rich in galactose and acidic sugars, a total soluble carbohydrate extraction was performed. Cellulose, as part of the insoluble carbohydrates, was isolated through alkaline and acid hydrolysis, while sodium silicate was derived from the ash. Characterization of insoluble cellulose and silicate involved techniques like FTIR, DSC, PXRD, microphotography, porosity assessments, and water absorption studies. For proteins, alkaline solubilization and precipitation at the isoelectric point were utilized, with quantification via BCA and amino acid profiling through gas chromatography. Evaluation of radical scavenging capacity using DPPH led to the calculation of apparent molecular weight via SDS-PAGE.

Results

The results revealed low levels of gum, mucilage, and pectin in both residues, contrasting with a high concentration of insoluble polysaccharides. Among these, Iβ cellulose displayed potential attributes for cosmetic applications due to its oil and water adsorption characteristics. However, silicates obtained from the ashes did not exhibit direct use potential. In terms of protein extraction, we observed antioxidant properties, with enhanced performance through enzymatic hydrolysis, achieving a hydrolysis degree of 30.41% and a DPPH radical absorption rate exceeding 70%.

Conclusion

Rice residues, particularly husk and straw, shown valuable substances suitable for potential cosmetic applications, encompassing cellulose, hydrolyzed proteins, and ash as a silicate precursor.

Kappaphycus alvarezii as a renewable source of kappa-carrageenan and other cosmetic ingredients

Kappa-carrageenan is one of the most traded marine-derived hydrocolloids used in the food-and-beverage, pharmaceuticals, and personal care/cosmetics industries. K. alvarezii (previously known as Kappaphycus alvarezii) is arguably the most important natural producer based on annual production size and near-homogeneity of the product (i.e., primarily being the kappa-type). The anticipated expansion of the kappa-carrageenan market in the coming years could easily generate >100,000 MT of residual K. alvarezii biomass per year, which, if left untreated, can severely affect the environment and economy of the surrounding area. Among several possible valorization routes, turning the biomass residue into anti-photoaging cosmetic ingredients could potentially be the most sustainable one. Not only optimizing the profit (thus better ensuring economic sustainability) relative to the biofuels- and animal feed-routes, the action could also promote environmental sustainability. It could reduce the dependency of the current cosmetic industry on both petrochemicals and terrestrial plant-derived bioactive compounds. Note how, in contrast to terrestrial agriculture, industrial cultivation of seaweeds does not require arable land, freshwater, fertilizers, and pesticides. The valorization mode could also facilitate the sequestration of more greenhouse gas CO2 as daily-used chemicals, since the aerial productivity of seaweeds is much higher than that of terrestrial plants. This review first summarizes any scientific evidence that K. alvarezii extracts possess anti-photoaging properties. Next, realizing that conventional extraction methods may prevent the use of such extracts in cosmetic formulations, this review discusses the feasibility of obtaining various K. alvarezii compounds using green methods. Lastly, a perspective on several potential challenges to the proposed valorization scheme, as well as the potential solutions, is offered.

Positive and ecobiological contribution in skin photoprotection of ectoine and mannitol combined in vivo with UV filters

BACKGROUND

Chronic exposure to ultraviolet (UV) irradiation causes immunosuppression, photoaging, and carcinogenesis by induction of a cascade of skin damages. Sunscreens currently on the market are not absorbing UV rays uniformly throughout the full UV range, high sun protection factor (SPF) sunscreens absorb most of UVB rays but are less effective in absorbing the UVA part of the spectrum. In the context, one approach could consist of preserving the skin natural resources and mechanisms, which is the foundation of the ecobiological approach, by combing UV filters and antioxidants to enhance their photoprotective effect.

METHODS

First, the photoprotection properties of ectoine and mannitol association were characterized by the quantification of glutathione, reactive oxygen species, and double-stranded DNA breaks and by the epidermal Langerhans cells functionality. Second, the protection of squalene oxidation, catalase activity, and trans-urocanic acid (UCA) by the ectoine and mannitol association combined or not with SPF30 UV filters was assessed in vivo via non-invasive skin samplings in 10 subjects on irradiated areas.

RESULTS

Using in vitro irradiated skin cell models, we demonstrated that this association significantly preserved intracellular glutathione levels, reduced DNA strand breaks induced by oxidative stress, and maintained Langerhans cell functionality. In vivo this association combined with UV filters presented significantly higher protection of three natural defense systems altered by UV compared to UV filters alone: squalene oxidation, catalase activity, and preservation of trans-UCA.

CONCLUSION

This study demonstrates the ecobiological potential of combining UV filters with biological protection to increase skin photoprotection provided by specific active ingredients with antioxidative and immunosuppressive properties.

Photoaging and Topical Rejuvenation

Photoaging is a complex process of skin changes associated with chronic ultraviolet exposure. Prevention with photoprotection and treatment with topical retinoids are the core components of a topical antiaging regimen. Other topicals such as hydroquinone, vitamin C, niacinamide, and alpha hydroxyl acid can be added based on specific concerns. However, caution must be used with some of these products as the stability and absorption are major considerations. A simple topical regimen will reduce irritability and enhance compliance.

Current Insights into the Formulation and Delivery of Therapeutic and Cosmeceutical Agents for Aging Skin

“Successful aging” counters the traditional idea of aging as a disease and is increasingly equated with minimizing age signs on the skin, face, and body. From this stems the interest in preventative aesthetic dermatology that might help with the healthy aging of skin, help treat or prevent certain cutaneous disorders, such as skin cancer, and help delay skin aging by combining local and systemic methods of therapy, instrumental devices, and invasive procedures. This review will discuss the main mechanisms of skin aging and the potential mechanisms of action for commercial products already on the market, highlighting the issues related to the permeation of the skin from different classes of compounds, the site of action, and the techniques employed to overcome aging. The purpose is to give an overall perspective on the main challenges in formulation development, especially nanoparticle formulations, which aims to defeat or slow down skin aging, and to highlight new market segments, such as matrikines and matrikine-like peptides. In conclusion, by applying enabling technologies such as those delivery systems outlined here, existing agents can be repurposed or fine-tuned, and traditional but unproven treatments can be optimized for efficacious dosing and safety.

Antioxidants in Sunscreens: Which and What For?

Ultraviolet (UV) radiation promotes the generation of reactive oxygen species (ROS) and nitrogen species (RNS), resulting in skin damage. Cosmetic industries have adopted a strategy to incorporate antioxidants in sunscreen formulations to prevent or minimize UV-induced oxidative damage, boost photoprotection effectiveness, and mitigate skin photoaging. Many antioxidants are naturally derived, mainly from terrestrial plants; however, marine organisms have been increasingly explored as a source of new potent antioxidant molecules. This work aims to characterize the frequency of the use of antioxidants in commercial sunscreens. Photoprotective formulations currently marketed in parapharmacies and pharmacies were analyzed with respect to the composition described on the label. As a result, pure compounds with antioxidant activity were found. The majority of sunscreen formulations contained antioxidants, with vitamin E and its derivatives the most frequent. A more thorough analysis of these antioxidants is also provided, unveiling the top antioxidant ingredients found in sunscreens. A critical appraisal of the scientific evidence regarding their effectiveness is also performed. In conclusion, this work provides an up-to-date overview of the use of antioxidants in commercial sunscreens for a better understanding of the advantages associated with their use in photoprotective formulations.

Valorization of agri-food waste through the extraction of bioactive molecules. Prediction of their sunscreen action

The aim of this work was to identify the phenolic composition of 18 different vegetable residues and to determine the relationship between their phenolic compounds, antioxidant capacity and sun protection factor. For this purpose, samples of agri-food residues were analyzed to quantify their antioxidant capacity, total polyphenol and flavonoid content, sun protection factor and individual phenolic compounds through HPLC-DAD-FLD. Among the different phenolic compounds found in the extracts, the phenolic acids, especially caffeic acid, chlorogenic acid, p-coumaric acid and protocatechuic acid were the ones that have been most frequently identified, and, therefore, are present in a wide range of extracts. Black chai tea, lemon ginger tea and peanut extracts were the most antioxidant and photoprotective extracts. Phenolic compounds in the extracts have been found to contribute to their antioxidant activity and are closely correlated to their photoprotective capacity. A regression model that allows predicting the photoprotective capacity of any extract based on its total phenol content has been developed as a tool to determine the most suitable industrial application for each vegetable extract.

Are TRPA1 and TRPV1 channel-mediated signalling cascades involved in UVB radiation-induced sunburn?

Burn injuries are underappreciated injuries associated with substantial morbidity and mortality. Overexposure to ultraviolet (UV) radiation has dramatic clinical effects in humans and is a significant public health concern. Although the mechanisms underlying UVB exposure are not fully understood, many studies have made substantial progress in the pathophysiology of sunburn in terms of its molecular aspects in the last few years. It is well established that the transient receptor potential ankyrin 1 (TRPA1), and vanilloid 1 (TRPV1) channels modulate the inflammatory, oxidative, and proliferative processes underlying UVB radiation exposure. However, it is still unknown which mechanisms underlying TRPV1/A1 channel activation are elicited in sunburn induced by UVB radiation. Therefore, in this review, we give an overview of the TRPV1/A1 channel-mediated signalling cascades that may be involved in the pathophysiology of sunburn induced by UVB radiation. These data will undoubtedly help to explain the various features of sunburn and contribute to the development of novel therapeutic approaches to better treat it.

Up-to-Date Overview of the Use of Natural Ingredients in Sunscreens

The photoprotective skincare segment is in high demand to meet consumer concerns on UV-induced skin damage, with a recent trend towards sunscreen alternatives with a natural origin. In this study, the use of natural ingredients, either from terrestrial or marine origin, in a panel of 444 sunscreen commercial formulations (2021) was analyzed. Ingredients from terrestrial organisms represent the large majority found in the analyzed sunscreen formulations (48%), whereas marine ingredients are present only in 13% of the analyzed products. A deeper analysis regarding the most prevalent families of ingredients from terrestrial and marine organisms used as top ingredients is also presented, as well as their mechanisms of action. This study provides an up-to-date overview of the sunscreen market regarding the use of natural ingredients, which is of relevance for scientists involved in the development of new sunscreens to identify opportunities for innovation.

Plant Secondary Metabolites against Skin Photodamage: Mexican Plants, a Potential Source of UV-Radiation Protectant Molecules

Human skin works as a barrier against the adverse effects of environmental agents, including ultraviolet radiation (UVR). Exposure to UVR is associated with a variety of harmful effects on the skin, and it is one of the most common health concerns. Solar UVR constitutes the major etiological factor in the development of cutaneous malignancy. However, more than 90% of skin cancer cases could be avoided with appropriate preventive measures such as regular sunscreen use. Plants, constantly irradiated by sunlight, are able to synthesize specialized molecules to fight against UVR damage. Phenolic compounds, alkaloids and carotenoids constitute the major plant secondary metabolism compounds with relevant UVR protection activities. Hence, plants are an important source of molecules used to avoid UVR damage, reduce photoaging and prevent skin cancers and related illnesses. Due to its significance, we reviewed the main plant secondary metabolites related to UVR protection and its reported mechanisms. In addition, we summarized the research in Mexican plants related to UV protection. We presented the most studied Mexican plants and the photoprotective molecules found in them. Additionally, we analyzed the studies conducted to elucidate the mechanism of photoprotection of those molecules and their potential use as ingredients in sunscreen formulas.

Photoprotection for skin of all color: Consensus and clinical guidance from an expert panel

The negative effects of sun exposure have become better accepted among health care professionals and the lay public over recent decades. Most attention has been focused on the effects of UV light, particularly UVB wavelengths (290-320 nm). Accordingly, products to protect skin from sunlight-associated harm (sunscreens) have been developed to minimize UVB exposure. The effects of longer wavelengths, including UVA (320-400 nm) and visible light (VL, 400-700 nm), are increasingly appreciated. VL accounts for approximately half of the solar radiation that reaches the earth's surface and understanding of its effects on the skin is improving. Studies have shown that VL can induce hyperpigmentation in individuals with dark skin types (Fitzpatrick skin types IV-VI). In addition, VL can contribute to the exacerbation of pigmentary disorders, including melasma. Because these findings are relatively new, there are gaps in understanding the needs for photoprotection and guidance for clinicians. A panel of dermatologists and photobiologists was convened to develop consensus recommendations and clinical guidance about sunscreen use relevant to the current understanding of risks associated with sun exposure using a modified Delphi method.

Sunscreens and Photoaging: A Review of Current Literature

Sunscreens have been on the market for many decades as a means of protection against ultraviolet-induced erythema. Over the years, evidence has also shown their efficacy in the prevention of photoaging, dyspigmentation, DNA damage, and photocarcinogenesis. In the USA, most broad-spectrum sunscreens provide protection against ultraviolet B (UVB) radiation and short-wavelength ultraviolet A (UVA) radiation. Evidence suggests that visible light and infrared light may play a role in photoaging and should be considered when choosing a sunscreen. Currently, there is a paucity of US FDA-approved filters that provide protection against long UVA (> 370 nm) and none against visible light. Additionally, various sunscreen additives such as antioxidants and photolyases have also been reported to protect against and possibly reverse signs of photoaging. This literature review evaluates the utility of sunscreen in protecting against photoaging and further explores the requirements for an ideal sunscreen.

Ascorbic acid 2-glucoside: An ascorbic acid pro-drug with longer-term antioxidant efficacy in skin

OBJECTIVE

Deleterious effects of pollutants and ultraviolet radiation on the skin can be attenuated using formulations containing antioxidants. However, these have disadvantages, including chemical instability, photodegradation, poor bioavailability or biological activity. Here, two commercial formulations were evaluated: one optimized to stabilize and deliver ascorbic acid (AA) at 15% and the other containing a glucoside form of AA, namely ascorbic acid 2-glucoside (AA2G), at 1.8% and at a physiological pH. We compared the skin delivery, antioxidative effects and chemical stability of AA2G with AA in their respective formulations.

METHODS

Skin delivery was measured using fresh viable human skin explants, and oxidative stress was measured using a human reconstructed epidermal (RHE) model according to levels of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase.

RESULTS

Ascorbic acid 2-glucoside was completely metabolized to AA by the skin before entering the receptor compartment. The skin contained parent and AA, indicating a reserve of AA2G was present for further metabolism. For AA2G and AA, maximum flux of AA-equivalents was at 12 h, with continued absorption over 24 h. The absolute amount in µg was higher in the skin after application of AA than after application of AA2G. This may suggest a greater antioxidative effect; however, according to all three measurements of oxidative stress, the protective effect of AA and AA2G was similar. Unlike AA, AA2G was chemically stable under storage conditions.

CONCLUSION

A lower concentration of AA2G is as effective as the active metabolite, AA, in terms of antioxidant effects. AA2G was chemically stable and can be applied at a lower concentration than AA, thus avoiding the need for an acidic formulation with a pH below 3.5.

Measurement of the Population of Electrosprayed Deprotomers of Coumaric Acids Using UV-Vis Laser Photodissociation Spectroscopy

The measurement of deprotonation sites in multifunctional molecules following electrospray ionization is important to better inform a wide range of spectroscopic and photophysical studies that use electrospray to prepare molecular species for study in the gas phase. We demonstrate that low-resolution UV-vis laser photodissociation spectroscopy can be applied in situ to identify the deprotomers of three coumaric acids, trans-para-coumaric acid (CMA), trans-caffeic acid (CA), and trans-ferulic acid (FA), formed via electrospray. Electronic absorption spectra of the deprotonated coumaric acids are recorded via photodepletion and photofragmentation following electrospray from solutions of ethanol and acetonitrile. By comparing the experimental spectra to wave function theory calculations, we are able to confirm the presence of phenoxide and carboxylate deprotomers upon electrospray for all three coumaric acids, when sprayed from both protic and aprotic solvents. Ratios of the phenoxide:carboxylate deprotomers are obtained by generating summed theoretical absorption spectra that reproduce the experimental spectra. We find that choice of electrospray solvent has little effect on the ratio of deprotomers obtained for deprotonated CMA and CA but has a greater impact for FA. Our results are in excellent agreement with previous work conducted on deprotonated CMA using IR spectroscopy and demonstrate that UV photodissociation spectroscopy of electrosprayed ions has potential as a diagnostic tool for identifying deprotomeric species.

Awareness of pharmacists and consumers towards protective effects of sunscreens against skin cancer

The objective of the present study was to assess the awareness level of individuals on the use of sunscreen products, and pharmacists' perception of sunscreen safety. A cross-sectional, descriptive study was conducted in the United Arab Emirates (UAE). Participants involved included 224 female undergraduates of Ajman University (aged 18-25 years old), 234 patients visiting numerous pharmacies, and 58 pharmacists from the private sector in Dubai. Questionnaires were designed and distributed to all participants. Data entry and analysis were performed using SPSS (Statistical Program for Social Sciences) version 20. Among female undergraduate students, 94.7% used sun protection, 81.1% understood what is meant by SPF (Sun Protection Factor) Value, and 70.2% used the optimal SPF (15-20). Additionally, 95.2% reported that sunscreens do not have any side effects. Out of the 234 patients who participated in the study, 86.8% used sun protection, 56.8% understood what is meant by SPF, and 43.2% used the optimal SPF. Furthermore, 93.2% stated that sunscreens do not have any side effects. Female patients were found to use sunscreens with higher SPF values (above 50) as compared to male patients (P ≤ 0.024). Patients above the age of 40 also used sunscreens with high SPF (P ≤ 0.001). As for pharmacists, they all agreed that sunscreens have a marked safety profile, with no side effects, and that the optimal SPF for use is 15-20. Most pharmacists (80%) reported that consumers are in fact aware and knowledgeable about the proper use and application of sunscreens. Optimal use of routine sunscreen is of paramount importance to prevent skin damage as well as cancer.

Potential of Olive Oil Mill Wastewater as a Source of Polyphenols for the Treatment of Skin Disorders: A Review

Current trends toward naturally occurring compounds of therapeutic interest have contributed to an increasing number of studies on olive oil phenolics in the treatment of diseases with oxidative and inflammatory origins. Recent focus has been on olive oil wastewater, which is richer in phenolic compounds than olive oil itself. In this review, we present findings demonstrating the potential use of olive mill wastewater in dermatology. Particular attention is given to compounds with proven benefits in topical pharmacology: caffeic and ferulic acids, tyrosol and hydroxytyrosol, verbascoside, and oleuropein. The review is divided into different sections: inflammatory skin diseases, microbial effects, wound healing in addition to the antimelanoma properties of olive mill waste phenolics, and their potential in sun protection agents. There is strong evidence to support further studies into the valorization of this abundant and sustainable source of phenolic compounds for use in dermatology and dermo-cosmetic preparations.

Sustained effect of two antioxidants (oxothiazolidine and δ-tocopheryl glucoside) for immediate and long-term sun protection in a sunscreen emulsion based on their different penetrating properties

OBJECTIVE

We investigated the dermal bioavailability and antioxidative properties of a sunscreen formulation containing two antioxidants, oxothiazolidine (OTZ) and δ-tocopheryl glucoside (DTG). OTZ reacts directly with reactive oxygen species to form taurine, while DTG is metabolized in δ-tocopherol to achieve antioxidative activities.

METHODS

After topical application to a hair follicle-derived reconstructed human epidermis (RHE) model, followed by solar-simulated radiation, kinetics of bioavailability and antioxidative responses were measured over 24 h. Markers for oxidative stress were malondialdehyde (MDA), superoxide dismutase (SOD) and catalase activities.

RESULTS

The two antioxidants had different bioavailability profiles: OTZ was rapidly and extensively absorbed, whereas DTG was slowly absorbed and converted to δ-tocopherol. Compared to OTZ alone, the protection against effects on MDA levels and SOD and catalase activities was higher when DTG was used alone or in combination with OTZ. When used in combination, the degree of protection increased over time and remained constant over 24 h with maximal protection 2 h post-irradiation. DTG slowly penetrated into the skin and was present in the skin at all post-irradiation timepoints, thus allowing a slow but constant supply of δ-tocopherol over at least 24 h. By contrast, the oxidative protection by OTZ was immediate but short-lived due to its rapid penetration through the RHE and into the receptor fluid.

CONCLUSION

These results indicate a complementary sunlight protective action of OTZ and DTG with an immediate delivery of OTZ just after topical application of the formulation, and a prolonged skin delivery of δ-tocopherol from the slower penetration and metabolism of DTG.

Natural components in sunscreens: Topical formulations with sun protection factor (SPF)

Artificial sunscreens are already gaining traction in order to protect the skin from sunburns, photoaging and photocarcinogenesis. However, the efficacy and safety of most artificial sunscreen constituents are hindered by their photostability, toxicity and damage to marine ecosystems. Natural selection and evolution have ensured that plants and animals have developed effective protective mechanisms against the deleterious side effects of oxidative stress and ultraviolet radiation (UV). Hence, natural antioxidants such as sun blockers are drawing considerable attention. The exact mechanism by which natural components act as sunscreen molecules has not been clearly established. However, conjugated π system is reported to play an important role in protecting the vital genetic material within the organism. Compared to artificial sunscreens, natural sunscreens with strong UV absorptive capacities are largely limited by low specific extinction value and by their inability to spread in large-scale sunscreen cosmetic applications. Previous studies have documented that natural components exert their photoprotective effects (such as improved skin elasticity and hydration, skin texture, and wrinkles) through their antioxidant effects, and through the regulation of UV-induced skin inflammation, barrier impairment and aging. This review focuses on natural antioxidant topical formulations with sun protection factor (SPF). Lignin, melanin, silymarin and other ingredients have been added to high sun protection nature sunscreens without any physical or chemical UV filters. This paper also provides a reference for adopting novel technical measures (extracting high content components, changing the type of solution, optimizing formulation, applying Nano technology, et al) to design and prepare nature sunscreen formulations equated with commercial sunscreen formulations. Another strategy is to add natural antioxidants from plants, animals, microorganisms and marine organisms as special enhancer or modifier ingredients to reinforce SPF values. Although the photoprotective effects of natural components have been established, their deleterious side effects have not been elucidated.

UVB photoprotective capacity of hydrogels containing dihydromyricetin nanocapsules to UV-induced DNA damage

We evaluate the effect of cationic nanocapsules containing dihydromyricetin (DMY) flavonoid for safe topical use in photoprotection against UV-induced DNA damage. The stability was investigated for feasibility to produce hydrogels containing cationic nanocapsules of the flavonoid DMY (NC-DMY) for 90 days under three different storage conditions (4 ± 2 °C, 25 ± 2 °C, and 40 ± 2 °C), as well as evaluation of skin permeation and its cytotoxicity in skin cell lines. The physicochemical and rheological characteristics were maintained during the analysis period under the different aforementioned conditions. However, at 25 °C and 40 °C, the formulations indicated yellowish coloration and DMY content reduction. Therefore, the ideal storage condition of 4 °C was adopted. DMY remained in the stratum corneum and the uppermost layers of the skin. Regarding safety, all formulations demonstrated to be safe for topical application. NC-DMY exhibited a 50% Solar Protection Factor (SPF-DNA) against DNA damage caused by UVB radiation and demonstrated 99.9% protection against DNA lesion induction. These findings establish a promising formulation containing nanoencapsulated DMY flavonoids with a photoprotective and antioxidant potential of eliminating reactive oxygen species formed by solar radiation.

Exploring the Photochemistry of an Ethyl Sinapate Dimer: An Attempt Toward a Better Ultraviolet Filter

The photochemistry and photostability of a potential ultraviolet (UV) radiation filter, dehydrodiethylsinapate, with a broad absorption in the UVA region, is explored utilizing a combination of femtosecond time-resolved spectroscopy and steady-state irradiation studies. The time-resolved measurements show that this UV filter candidate undergoes excited state relaxation after UV absorption on a timescale of ~10 picoseconds, suggesting efficient relaxation. However, steady-state irradiation measurements show degradation under prolonged UV exposure. From a photochemical standpoint, this highlights the importance of considering both the ultrafast and “ultraslow” timescales when designing new potential UV filters.

Streptomyces-Derived Metabolites with Potential Photoprotective Properties-A Systematic Literature Review and Meta-Analysis on the Reported Chemodiversity

Sun overexposure is associated with the development of diseases that primarily affect the skin, which can lead to skin cancer. Among the main measures of photoprotection is the use of sunscreens. However, there is currently concern about the reported harmful effects to both humans and the environment due to several of the sunscreen ingredients available on the market. For this reason, the search for and development of new agents with photoprotective properties is required. In searching for these metabolites, researchers have turned their attention to microbial sources, especially the microbiota in unusual hostile environments. Among the diverse microorganisms available in nature, Actinobacteria and specifically Streptomyces, have been shown to be a source of metabolites with various biological activities of interest, such as antimicrobial, antitumor and immunomodulator activities. Herein, we present the results of a systematic review of the literature in which Streptomyces isolates were studied as a source of compounds with photoprotective properties. A meta-analysis of the structure-property and structure-activity relationships of those metabolites identified in the qualitative analysis phase was also carried out. These findings indicate that Streptomyces are a source of metabolites with potential applications in the development of new, safe and more eco-friendly sunscreens.

Efficacy, Stability, and Safety Evaluation of New Polyphenolic Xanthones Towards Identification of Bioactive Compounds to Fight Skin Photoaging

Antioxidants have long been used in the cosmetic industry to prevent skin photoaging, which is mediated by oxidative stress, making the search for new antioxidant compounds highly desirable in this field. Naturally occurring xanthones are polyphenolic compounds that can be found in microorganisms, fungi, lichens, and some higher plants. This class of polyphenols has a privileged scaffold that grants them several biological activities. We have previously identified simple oxygenated xanthones as promising antioxidants and disclosed as hit, 1,2-dihydroxyxanthone (1). Herein, we synthesized and studied the potential of xanthones with different polyoxygenated patterns as skin antiphotoaging ingredients. In the DPPH antioxidant assay, two newly synthesized derivatives showed IC₅₀ values in the same range as ascorbic acid. The synthesized xanthones were discovered to be excellent tyrosinase inhibitors and weak to moderate collagenase and elastase inhibitors but no activity was revealed against hyaluronidase. Their metal-chelating effect (FeCl₃ and CuCl₂) as well as their stability at different pH values were characterized to understand their potential to be used as future cosmetic active agents. Among the synthesized polyoxygenated xanthones, 1,2-dihydroxyxanthone (1) was reinforced as the most promising, exhibiting a dual ability to protect the skin against UV damage by combining antioxidant/metal-chelating properties with UV-filter capacity and revealed to be more stable in the pH range that is close to the pH of the skin. Lastly, the phototoxicity of 1,2-dihydroxyxanthone (1) was evaluated in a human keratinocyte cell line and no phototoxicity was observed in the concentration range tested.

Exploring the Potential Use of Hylocereus polyrhizus Peels as a Source of Cosmeceutical Sunscreen Agent for Its Antioxidant and Photoprotective Properties

Currently, consumers' demand for sunscreens derived from natural sources that provide photoprotection from ultraviolet (UV) radiation is pushing the cosmetic industry to develop breakthrough formulations of sun protection products by incorporating plant antioxidants as their active ingredients. In this context, the present study was initiated to evaluate the antioxidant and photoprotective properties of the underutilized Hylocereus polyrhizus peel extract (HPPE) using in vitro spectrophotometric techniques. The phytochemical screenings of HPPE conducted via high-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) revealed the presence of phenolic acids and flavonoids as the major secondary metabolites in HPPE. The antioxidant potentials evaluated based on 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical and total antioxidant capacity assays were in the range of 22.16 ± 0.24%-84.67 ± 0.03% with 50% inhibitory concentration (IC50) of 36.39 ± 0.04 μg/mL and 23.76 ± 0.14%-31.87 ± 0.26% (IC50 = 21.93 ± 0.07 μg/mL), respectively. For the photoprotective evaluation, the results showed that HPPE had significantly high absorbance values (3.1-3.6) at 290-320 nm with an exceptional sun protection factor (SPF) value of 35.02 ± 0.39 at 1.00 mg/mL. HPPE also possessed a broad-spectrum shielding power against both UVA and UVB radiations. Hence, in terms of practical implications, our findings would offer an exciting avenue to develop a photoprotective formulation incorporating the ethanolic extract of Hylocereus polyrhizus peels as a synergistic active ingredient for its excellent UV absorption properties and the strong antioxidant activities.

Can natural products improve skin photoprotection?

Abstract Due to increased UV radiation on the Earth’s surface, caused by depletion of the stratospheric ozone, people have become more susceptible to different types of skin damage, such as erythema, sunburns, and cancer; this is especially of concern in tropical countries. Thus, efforts to improve awareness as well as the use of sunscreen are increasing worldwide. However, synthetic UV filters have been associated with deleterious effects such as photosensitization. Natural products have been used by ancient cultures for several purposes, including protecting the skin from the sun. However, there is still doubt today whether photoprotection is a real phenomenom or whether it is simply tanning of the skin. Plants have self-protective mechanisms and produce secondary metabolites that can protect themselves from UV radiation. Yet, can phytochemical compounds protect human skin? This review discusses the paradoxical effect of chemical UV filters and the influence of phytochemicals in in vitro and in vivo tests of photoprotection.

Open-label study assessing the efficacy and tolerability of topical skin care and sun protection alone and in combination with intense pulsed light therapy

BACKGROUND

Intense pulsed light therapy (IPL) decreases facial erythema and telangiectasias associated with rosacea. Topical skin care products decrease facial erythema by the action of active ingredients and masking effects.

OBJECTIVES

To assess the efficacy and tolerability of combining a topical skin care regimen (TSCR) comprised of a multifunctional three-in-one facial cream and a mineral-based brush-on SPF50 powder sunscreen with a single IPL treatment for treating mild-to-severe facial redness associated with rosacea.

METHODS

Twenty female subjects with Fitzpatrick skin types I-III received TSCR monotherapy for 12 weeks. At that time, subjects received a single IPL treatment and continued TSCR for 6 additional weeks. Subjects were evaluated at Baseline and at Weeks 4, 8, 12, and 18.

RESULTS

Using a 7-point redness scale, the overall mean (SD) redness score significantly improved from 3.05 (0.97) at baseline to 2.05 (0.76) at Week 18 (P < 0.01). There was a decrease in investigator-rated erythema from baseline (bare skin) to Week 12 (bare skin, before IPL) when TSCR was used as monotherapy which did not achieve significance (P = 0.12). Most subjects (80%) were satisfied or Very satisfied with the TSCR at Week 18. All subjects (100%) agreed that it improved their baseline skin redness and most (85%) would recommend TSCR to others. TSCR was well-tolerated with no significant changes in skin dryness, scaling, or itching. Mild burning occurred immediately following the IPL treatment at Week 12.

CONCLUSION

TSCR in combination with a single IPL treatment produced a significant improvement in overall facial redness in patients with rosacea. Longer-term treatment with TSCR may produce continued improvement.

KLF9-dependent ROS regulate melanoma progression in stage-specific manner

Although antioxidants promote melanoma metastasis, the role of reactive oxygen species (ROS) in other stages of melanoma progression is controversial. Moreover, genes regulating ROS have not been functionally characterized throughout the entire tumor progression in mouse models of cancer. To address this question, we crossed mice-bearing knock-out of Klf9, an ubiquitous transcriptional regulator of oxidative stress, with two conditional melanocytic mouse models: Braf^CA mice, where Braf^V600E causes premalignant melanocytic hyperplasia, and Braf^CA/Pten^-/- mice, where Braf^V600E and loss of Pten induce primary melanomas and metastases. Klf9 deficiency inhibited premalignant melanocytic hyperplasia in Braf^CA mice but did not affect formation and growth of Braf^CA/Pten^-/- primary melanomas. It also, as expected, promoted Braf^CA/Pten^-/- metastasis. Treatment with antioxidant N-acetyl cysteine phenocopied loss of Klf9 including suppression of melanocytic hyperplasia. We were interested in a different role of Klf9 in regulation of cell proliferation in Braf^CA and Braf^CA/Pten^-/- melanocytic cells. Mechanistically, we demonstrated that BRAF^V600E signaling transcriptionally upregulated KLF9 and that KLF9-dependent ROS were required for full-scale activation of ERK1/2 and induction of cell proliferation by BRAF^V600E. PTEN depletion in BRAF^V600E-melanocytes did not further activate ERK1/2 and cell proliferation, but rendered these phenotypes insensitive to KLF9 and ROS. Our data identified an essential role of KLF9-dependent ROS in BRAF^V600E signaling in premalignant melanocytes, offered an explanation to variable role of ROS in premalignant and transformed melanocytic cells and suggested a novel mechanism for suppression of premalignant growth by topical antioxidants.

Study of the synergic effect between mica and biosurfactant to stabilize Pickering emulsions containing Vitamin E using a triangular design

HYPOTHESIS

Vitamin E has interesting biological functions for the cosmetic and pharmaceutical industry because it can act as a fat-soluble antioxidant, as well as peroxyl radical scavenger. However, this vitamin is formed by a group of compounds that include tocopherols (γ-tocopherols, α-tocopherol) characterized by their poor solubility in water, what implies the need of using stabilizing agents such as biosurfactants or minerals, in order to make them soluble or stable in formulations composed by water and oil.

EXPERIMENTS

In this work, it has been evaluated the synergic effect between a mining silicate mineral (mica) and a biosurfactant extract, obtained from corn steep liquor, to stabilize emulsions containing water and a non-aqueous soluble antioxidant consisting of Vitamin E, through the use of a triangular design.

FINDINGS

The results show that the presence of biosurfactant extract improves the emulsion volume up to 70% after 22 days, for an emulsion composed of Vitamin E and biosurfactant, whereas the mica component was able to increase the emulsion stability until values of 80% after 30 days of experiment, for those emulsions containing 10% of mica. Hence, both novel ingredients produce a synergistic effect on the Pickering emulsions carried out in the study.

Antioxidants in dermatology

The skin cells continuously produce, through cellular respiration, metabolic processes or under external aggressions, highly reactive molecules oxidation products, generally called free radicals. These molecules are immediately neutralized by enzymatic and non-enzymatic systems in a physiological and dynamic balance. In situations where this balance is broken, various cellular structures, such as the cell membrane, nuclear or mitochondrial DNA may suffer structural modifications, triggering or worsening skin diseases. several substances with alleged antioxidant effects has been offered for topical or oral use, but little is known about their safety, possible associations and especially their mechanism of action. The management of topical and oral antioxidants can help dermatologist to intervene in the oxidative processes safely and effectively, since they know the mechanisms, limitations and potential risks of using these molecules as well as the potential benefits of available associations.

Vitamin E inhibits the UVAI induction of "light" and "dark" cyclobutane pyrimidine dimers, and oxidatively generated DNA damage, in keratinocytes

Solar ultraviolet radiation (UVR)-induced DNA damage has acute, and long-term adverse effects in the skin. This damage arises directly by absorption of UVR, and indirectly via photosensitization reactions. The aim of the present study was to assess the effects of vitamin E on UVAI-induced DNA damage in keratinocytes in vitro. Incubation with vitamin E before UVAI exposure decreased the formation of oxidized purines (with a decrease in intracellular oxidizing species), and cyclobutane pyrimidine dimers (CPD). A possible sunscreening effect was excluded when similar results were obtained following vitamin E addition after UVAI exposure. Our data showed that DNA damage by UVA-induced photosensitization reactions can be inhibited by the introduction of vitamin E either pre- or post-irradiation, for both oxidized purines and CPD (including so-called “dark” CPDs). These data validate the evidence that some CPD are induced by UVAI initially via photosensitization, and some via chemoexcitation, and support the evidence that vitamin E can intervene in this pathway to prevent CPD formation in keratinocytes. We propose the inclusion of similar agents into topical sunscreens and aftersun preparations which, for the latter in particular, represents a means to mitigate on-going DNA damage formation, even after sun exposure has ended.

The extended production of UV-induced reactive oxygen species in L929 fibroblasts is attenuated by posttreatment with Arrabidaea chica through scavenging mechanisms

Ultraviolet radiation (UVR) exposure causes various injurious effects to human skin by generating reactive oxygen species (ROS). Excessive ROS production can lead to oxidative stress which may damage cellular components like lipids and proteins and causing photoaging. The use of natural photochemopreventive agents with antioxidant properties is an important alternative to improve the effectiveness of sunscreens and reduce skin photodamage. A crude extract (CE) from the leaves of Arrabidaea chica underwent partition by a liquid-liquid method. The hexane fraction (FH), chloroform fraction (FC), and ethyl acetate fraction (FEA) were obtained. The antioxidant capacity of the CE, FH, FC, and FEA was studied in a cell-free system using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and the xanthine/luminol/xanthine oxidase system. The FC had the best antioxidant activity. We also evaluated the photochemoprotective effect of A. chica in protecting L929 fibroblasts against UV-A- and UV-B-induced cell damage. A. chica inhibited the extended production of ROS up to 3h. Posttreatment with the CE and FC attenuated UV-induced cell damage through scavenging mechanisms, including the quenching of intracellular ROS and mitochondrial O₂^- and preventing lipid peroxidation. These results suggest that A. chica may be a promising non-sunscreen photoprotector that can improve the effectiveness of commercial sunscreens.

The activation of PPARγ by 2,4,6-Octatrienoic acid protects human keratinocytes from UVR-induced damages

Increasing attention is addressed to identify products able to enhance skin photoprotection and to prevent skin carcinogenesis. Several studies have demonstrated that the α-melanocyte stimulating hormone (αMSH), acting on a functional MC1R, provides a photoprotective effect by inducing pigmentation, antioxidants and DNA repair. We discovered a link between αMSH and the nuclear receptor Peroxisome Proliferator-Activated Receptor-γ (PPARγ), suggesting that some of the αMSH protective effects may be dependent on PPARγ transcriptional activity. Moreover, we demonstrated that the activation of PPARγ by the parrodiene 2,4,6-octatrienoic acid (Octa) induces melanogenesis and antioxidant defence in human melanocytes and counteracts senescence-like phenotype in human fibroblasts. In this study, we demonstrate that the activation of PPARγ by Octa exerts a protective effect against UVA- and UVB-induced damage on normal human keratinocytes (NHKs), the major target cells of UV radiation. Octa promotes the antioxidant defence, augments DNA repair and reduces the induction of proteins involved in UV-induced DNA damage response. Our results contribute to deepen the analysis of the αMSH/PPARγ connection and suggest perspectives for the development of new molecules and formulations able to prevent cutaneous UV damage by acting on the different skin cell populations through PPARγ activation.

Skin Delivery of EGCG and Silibinin: Potential of Peptide Dendrimers for Enhanced Skin Permeation and Deposition

The aim of the present study was to evaluate the ability of the peptide dendrimers to facilitate transdermal delivery of antioxidants, silibinin, and epigallocatechin-3-gallate (EGCG). Drug-peptide dendrimer complexes were prepared and evaluated for their ability to permeate across the skin. The data revealed the ready formation of complexes between drug and peptide dendrimer in a molar ratio of 1:1. In vitro permeation studies using excised rat skin and drug-peptide dendrimer complexes showed highest values for cumulative drug permeation at the end of 12 h (Q₁₂), with corresponding permeability coefficient (Kp) and enhancement ratio values also determined at this time point. With silibinin, 3.96-, 1.81-, and 1.06-fold increase in skin permeation was observed from silibinin-peptide dendrimer complex, simultaneous application of silibinin + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. With EGCG, 9.82-, 2.04-, and 1.72-fold increase in skin permeation was observed from EGCG-peptide dendrimer complex, simultaneous application of EGCG + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. The present study demonstrates the application of peptide dendrimers in effectively delivering antioxidants such as EGCG and silibinin into the skin, thus offering the potential to provide antioxidant effects when delivered via appropriately formulated topical preparations.

Melanoma Chemoprevention: Current Status and Future Prospects

The incidence of skin cancers, both nonmelanoma and melanoma, is increasing in the United States. The ultraviolet radiation, mainly from sun, is considered the major cause for these neoplasms. While nonmelanoma skin cancers are far more numerous, melanoma remains the most challenging. This is because melanoma can become extremely aggressive and its incidence is increasing worldwide due to lack of effective early detection, as well as disease recurrence, following both surgery and chemotherapy. Therefore, in addition to better treatment options, newer means are required to prevent melanomas from developing. Chemoprevention is a reasonable cost-effective approach to prevent carcinogenesis by inhibiting the processes of tumor initiation, promotion and progression. Melanoma is a progressive disease, which makes it very suitable for chemopreventive interventions, by targeting the processes and molecular pathways involved in the progression of melanoma. This review discusses the roles of various chemopreventive agents such as NSAIDs, statins, vitamins and dietary agents in melanoma and highlights current advancements and our perspective on future of melanoma chemoprevention. Although considerable preclinical data suggest that melanoma may be prevented or delayed by a numerous chemopreventive agents, we realize there are insufficient clinical studies evaluating their efficacy and long-term safety for human use.

Hydroxycinnamic Acids and Their Derivatives: Cosmeceutical Significance, Challenges and Future Perspectives, a Review

Bioactive compounds from natural sources, due to their widely-recognized benefits, have been exploited as cosmeceutical ingredients. Among them, phenolic acids emerge with a very interesting potential. In this context, this review analyzes hydroxycinnamic acids and their derivatives as multifunctional ingredients for topical application, as well as the limitations associated with their use in cosmetic formulations. Hydroxycinnamic acids and their derivatives display antioxidant, anti-collagenase, anti-inflammatory, antimicrobial and anti-tyrosinase activities, as well as ultraviolet (UV) protective effects, suggesting that they can be exploited as anti-aging and anti-inflammatory agents, preservatives and hyperpigmentation-correcting ingredients. Due to their poor stability, easy degradation and oxidation, microencapsulation techniques have been employed for topical application, preventing them from degradation and enabling a sustained release. Based on the above findings, hydroxycinnamic acids present high cosmetic potential, but studies addressing the validation of their benefits in cosmetic formulations are still scarce. Furthermore, studies dealing with skin permeation are scarcely available and need to be conducted in order to predict the topical bioavailability of these compounds after application.

Naringenin improves the sunscreen performance of vegetable nanocarriers

Naringenin enhances the UV protection, photostability and cell viability of lipid based vegetable nanocarriers.

Ganoderma lucidum polysaccharides protect fibroblasts against UVB-induced photoaging

Ganoderma lucidum has featured in traditional Chinese medicine for >1,000 years. Ganoderma polysaccharides (GL-PS), a major active ingredient in Ganoderma, confer immune regulation, antitumor effects and significant antioxidant effects. The aim of the present study was to investigate the efficacy and mechanism of GL‑PS‑associated inhibition of ultraviolet B (UVB)‑induced photoaging in human fibroblasts in vitro. Primary human skin fibroblasts were cultured, and a fibroblast photoaging model was built through exposure to UVB. Cell viability was measured by MTT assay. Aged cells were stained using a senescence‑associated β-galactosidase staining (SA‑β‑gal) kit. ELISA kits were used to analyze matrix metalloproteinase (MMP) ‑1 and C‑telopeptides of Type I collagen (CICP) protein levels in cellular supernatant. ROS levels were quantified by flow cytometry. Cells exposed to UVB had decreased cell viability, increased aged cells, decreased CICP protein expression, increased MMP‑1 protein expression, and increased cellular ROS levels compared with non‑exposed cells. However, cells exposed to UVB and treated with 10, 20 and 40 µg/ml GL‑PS demonstrated increased cell viability, decreased aged cells, increased CICP protein expression, decreased MMP‑1 protein expression, and decreased cellular ROS levels compared with UVB exposed/GL‑PS untreated cells. These results demonstrate that GL‑PS protects fibroblasts against photoaging by eliminating UVB‑induced ROS. This finding indicates GL‑PS treatment may serve as a novel strategy for antiphotoaging.

Current challenges in photoprotection

Electromagnetic radiation in the ultraviolet, visible, and infrared ranges all produce biologic effects. Ultraviolet filters are the most well-studied photoprotective measure for the adverse effects of ultraviolet radiation. Because of the reported endocrinologic effects of oxybenzone in animal studies, its effects on coral reefs, and its photocontact allergy potential, its use has been minimized in many countries worldwide. New developments in topical antioxidants and oral and subcutaneous agents (eg, Polypodium leucotomos extract, afamelanotide, nicotinamide) with photoprotective and antiphotocarcinogenic properties could potentially provide addition modalities for protection against the effects of visible light and infrared radiation.

Photodynamics of potent antioxidants: ferulic and caffeic acids

The dynamics of ferulic acid (3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid) and caffeic acid (3-(3,4-dihydroxyphenyl)-2-propenoic acid) in acetonitrile, dioxane and water at pH 2.2 following photoexcitation to the first excited singlet state are reported. These hydroxycinnamic acids display both strong ultraviolet absorption and potent antioxidant activity, making them promising sunscreen components. Ferulic and caffeic acids have previously been shown to undergo trans-cis photoisomerization via irradiation studies, yet time-resolved measurements were unable to observe formation of the cis-isomer. In the present study, we are able to observe the formation of the cis-isomer as well as provide timescales of relaxation following initial photoexcitation.

Topical Products for the Aging Face

This article focuses on nonprescription home-use topical treatment technologies for the aging face and is intended to serve as a guide for the core cosmeceutical technologies currently used and to help educate and assist the selection of topical antiaging products by the professional staff and their patients. Antiaging topical treatments for patient home use should be nonirritating, compatible with the patient skin type, effective, and complementary to surgical and minimally invasive office procedures, and aesthetically elegant. New topical antiaging technologies, formulated as monotherapy or as combinations with well-known cosmeceuticals, should present adequate clinical studies to support their selection for use.