The antioxidant system of the human body plays a crucial role in maintaining redox homeostasis and has an important protective function. Carotenoids have pronounced antioxidant properties in the neutralization of free radicals. In human skin, carotenoids have a high concentration in the stratum corneum (SC)—the horny outermost layer of the epidermis, where they accumulate within lipid lamellae. Resonance Raman spectroscopy and diffuse reflectance spectroscopy are optical methods that are used to non-invasively determine the carotenoid concentration in the human SC in vivo. It was shown by electron paramagnetic resonance spectroscopy that carotenoids support the entire antioxidant status of the human SC in vivo by neutralizing free radicals and thus, counteracting the development of oxidative stress. This review is devoted to assembling the kinetics of the carotenoids in the human SC in vivo using non-invasive optical and spectroscopic methods. Factors contributing to the changes of the carotenoid concentration in the human SC and their influence on the antioxidant status of the SC in vivo are summarized. The effect of chemotherapy on the carotenoid concentration of the SC in cancer patients is presented. A potential antioxidant-based pathomechanism of chemotherapy-induced hand-foot syndrome and a method to reduce its frequency and severity are discussed.

/pdf/carotenoids-in-human-skin-in-vivo-antioxidant-and-photo-gbp2w06t.pdf

Carotenoids in Human Skin In Vivo: Antioxidant and Photo-Protectant Role against External and Internal Stressors

Melasma is a frequent photoexacerbated hyperpigmentary disorder, which can significantly impact on the quality of life. We sought to review the pathogenesis of melasma, and the role of photoprotection in the prevention and treatment of this disorder.

Melasma: The need for tailored photoprotection to improve clinical outcomes

Our current understanding of the pathogenesis of skin aging includes the role of ultraviolet light, visible light, infrared, pollution, cigarette smoke and other environmental exposures. The mechanism of action common to these exposures is the disruption of the cellular redox balance by the directly or indirectly increased formation of reactive oxygen species that overwhelm the intrinsic antioxidant defense system, resulting in an oxidative stress condition. Altered redox homeostasis triggers downstream pathways that contribute to tissue oxinflammation (cross-talk between inflammation and altered redox status) and accelerate skin aging. In addition, both ultraviolet light and pollution increase intracellular free iron that catalyzes reactive oxygen species generation via the Fenton reaction. This disruption of iron homeostasis within the cell further promotes oxidative stress and contributes to extrinsic skin aging. More recent studies have demonstrated that iron chelators can be used topically and can enhance the benefits of topically applied antioxidants. Thus, an updated, more comprehensive approach to environmental or atmospheric aging protection should include sun protective measures, broad spectrum sunscreens, antioxidants, chelating agents, and DNA repair enzymes.

/pdf/ultraviolet-light-protection-is-it-really-enough-28bb2qos.pdf

Ultraviolet Light Protection: Is It Really Enough?

Nanosized antioxidants are highly advantageous in terms of versatility and pharmacokinetics, with respect to conventional molecular ones. Melanin-like materials, artificial species inspired by natural melanin, combine recognized antioxidant (AOX) activity with a unique versatility of preparation and modification. Due to this versatility and documented biocompatibility, artificial melanin has been incorporated into a variety of nanoparticles (NP) in order to give new platforms for nanomedicine with enhanced AOX activity. In this review article, we first discuss the chemical mechanisms behind the AOX activity of materials in the context of the inhibition of the radical chain reaction responsible for the peroxidation of biomolecules. We also focus briefly on the AOX properties of melanin-like NP, considering the effect of parameters such as size, preparation methods and surface functionalization on them. Then, we consider the most recent and relevant applications of AOX melanin-like NPs that are able to counteract ferroptosis and be involved in the treatment of important diseases that affect, e.g., the cardiovascular and nervous systems, as well as the kidneys, liver and articulations. A specific section will be dedicated to cancer treatment, since the role of melanin in this context is still very debated. Finally, we propose future strategies in AOX development for a better chemical understanding of melanin-like materials. In particular, the composition and structure of these materials are still debated, and they present a high level of variability. Thus, a better understanding of the mechanism behind the interaction of melanin-like nanostructures with different radicals and highly reactive species would be highly advantageous for the design of more effective and specific AOX nano-agents.

https://www.mdpi.com/2076-3921/12/4/863/pdf?version=1680437098

Recent Applications of Melanin-like Nanoparticles as Antioxidant Agents

Availability of new UV filters in the United States lags behind the European Union (EU), partly due to differing approval processes.To review available human safety data of all US- and EU-approved UV filters.Data from Food and Drug Administration and EU regulatory guidelines, federal governmental documentation, databases, reviews, and opinions for approval and ongoing safety evaluation were analyzed.Currently, there are 17 US UV filters and 29 EU UV filters (18 EU-approved only filters). Almost all US filters possessed sensitization data (94%, 16/17) with the majority (76%, 13/17) showing minimal skin sensitization. The minority of EU-approved only filters (33%, 6/18) possessed sensitization data, all showing no sensitization. Some filters possessed dermal absorption data (US: 76%, 13/17; EU: 44%, 8/18). Oxybenzone, octinoxate, octisalate, homosalate, and octocrylene, approved in the US and EU, were shown to have plasma levels exceeding the Food and Drug Administration exposure threshold.Proprietary manufacturer human data were unavailable.Many new UV filters are available in the EU, but not yet in the United States. Rigorous US and EU guidelines ensure that UV filters provide adequate photoprotection assuming consumers follow American Academy of Dermatology SPF (sun protection factor) and broad-spectrum recommendations. Human data are limited, but known human risks of sunscreen appear minimal. 

Ultraviolet filters in the United States and European Union: A review of safety and implications for the future of US sunscreens.

Until recently, the primary focus of photobiology has centered on the impact of UV radiation on skin health, including DNA damage and oncogenesis; however, the significant effects of visible light (VL) on skin remain grossly underreported. VL has been reported to cause erythema in individuals with light skin (Fitzpatrick skin types [FSTs] I-III) and pigmentary changes in individuals with dark skin types (FSTs IV-VI). These effects have importance in dermatologic diseases and potentially play a role in conditions aggravated by sun exposure, including phototoxicity in patients with FSTs I to III and post-inflammatory hyperpigmentation and melasma in patients with FSTs IV to VI. The induction of free radicals, leading to the generation of reactive species, is one driving mechanism of VL-induced skin pathologies, leading to the induction of melanogenesis and hyperpigmentation. Initial clinical studies have demonstrated the effectiveness of topical sunscreen with antioxidant combinations in inhibiting VL + UV-A1-induced erythema in FSTs I to III and reducing pigmentation in FSTs IV to VI. Antioxidants may help prevent the worsening of pigmentary disorders and can be incorporated into photoprotective strategies. It is essential that dermatologists and the public are aware of the impact of VL on skin, especially in patients with skin of color, and understand the available options for VL protection. 

http://www.jaad.org/article/S0190962221029893/pdf

Impact of visible light on skin health: The role of antioxidants and free radical quenchers in skin protection

To the Editor: On September 24, 2021, the US Food and Drug Administration (FDA) released a proposed final administrative order for sunscreen drug products.1United States Food and Drug Administration. OTC [email protected] Accessed September 25, 2021. https://www.accessdata.fda.gov/drugsatfda_docs/omuf/OTCMonograph_M020-SunscreenDrugProductsforOTCHumanUse09242021.pdfGoogle Scholar,2United States Food and Drug AdministrationQuestions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen.https://www.fda.gov/drugs/understanding-over-counter-medicines/questions-and-answers-fda-posts-deemed-final-order-and-proposed-order-over-counter-sunscreenDate accessed: September 25, 2021Google Scholar The release of this proposed order replaces the 2019 Proposed Rule in order to fulfill the statutory provisions of the Coronavirus Aid, Relief, and Economic Security Act, signed into law on March 27, 2020. The Coronavirus Aid, Relief, and Economic Security Act replaced the FDA monograph rulemaking process, which is laborious and time-consuming, with an administrative order process that should be more efficient.3Mohammad T.F. Lim H.W. The important role of dermatologists in public education on sunscreens.JAMA Dermatol. 2021; 157: 509-511https://doi.org/10.1001/jamadermatol.2020.5393Crossref PubMed Scopus (2) Google Scholar There is a 45-day comment period. After the FDA addresses all comments, a final administrative order will be issued, which would become effective no sooner than 1 year after its release. Once the final order is issued, companies will only be able to continue marketing sunscreens with a given active ingredient if the FDA has determined the active ingredient is generally recognized as safe and effective (GRASE), unless they first seek FDA approval. Until then, the FDA does not require companies to remove products from the market. Highlights of the proposed order, which is similar to the FDA Proposed Rule released in February 2019,4Wang S.Q. Lim H.W. Highlights and implications of the 2019 proposed rule on sunscreens by the US Food and Drug Administration.J Am Acad Dermatol. 2019; 81: 650-651https://doi.org/10.1016/j.jaad.2019.04.007Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar are shown below:1.GRASE status of approved UV filters:GRASE: zinc oxide and titanium dioxide;Not GRASE due to safety issues: paraaminobenzoic acid and trolamine salicylate;Not GRASE because additional data are needed (12 ingredients): cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone. Of note, paraaminobenzoic acid and trolamine salicylate are no longer used in sunscreens marketed in the US. For the other 12 ingredients with “not GRASE” status, if data are not available at the end of the 45-day comment period, the FDA would be prepared to defer the final decision on the ingredients provided the FDA is satisfied that timely progress is being made on the necessary studies. Such a deferral would be for a period of not more than 1 year, with a possible extension. At the time of this writing, industry is working with the FDA on testing requirements for 8 of the 12 ingredients. These 8 are avobenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, and oxybenzone.2.Maximum sun protection factor: 60+. However, marketing of products with a sun protection factor of up to 80 would be permissible.3.Broad spectrum requirements: These would be required for all products with a sun protection factor of ≥15; a proposed new requirement of a UV-A I/UV ratio of 0.7 or higher would need to be met.4.Dosage forms: Oils, lotions, creams, gels, butters, pastes, ointments, and sticks are proposed to be GRASE. Sprays, subject to testing and labeling requirements, are also proposed to be GRASE. Additional data are needed for powders before a determination of GRASE status can be made.5.Labeling: Active ingredients are to be listed alphabetically on the principal display panel (ie, the panel visible on the retail shelf).6.Sunscreen-insect repellent combinations: These products are proposed to be considered not GRASE. Dr Lim is an investigator for Incyte, L'Oréal, Pfizer, and PCORI. He has served as consultant for Pierre Fabre, ISDIN, Ferndale, La Roche-Posay, Cantabria, and Beiersdorf. He has also participated as a speaker in general educational sessions for La Roche-Posay and Cantabria Labs. Dr Mohammad is an investigator for Incyte, Pfizer, Arcutis, National Institute of Allergy and Infectious Diseases, and Unigen. Dr Wang has served as a speaker for La Roche-Posay and Neutrogena. 

http://www.jaad.org/article/S0190962221025639/pdf

Food and Drug Administration's proposed sunscreen final administrative order: How does it affect sunscreens in the United States?

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Isabel Giralt-Sampedro

Author Tools

Chat about Author

Papers

Impact of visible light on skin health: The role of antioxidants and free radical quenchers in skin protection

Food and Drug Administration's proposed sunscreen final administrative order: How does it affect sunscreens in the United States?

Food and Drug Administration's proposed sunscreen final administrative order: How does it affect sunscreens in the United States?