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Molecules (Basel, Switzerland) Mar 2020Direct sun exposure is one of the most aggressive factors for human skin. Sun radiation contains a range of the electromagnetic spectrum including UV light. In addition... (Review)
Review
Direct sun exposure is one of the most aggressive factors for human skin. Sun radiation contains a range of the electromagnetic spectrum including UV light. In addition to the stratospheric ozone layer filtering the most harmful UVC, human skin contains a photoprotective pigment called melanin to protect from UVB, UVA, and blue visible light. This pigment is a redox UV-absorbing agent and functions as a shield to prevent direct UV action on the DNA of epidermal cells. In addition, melanin indirectly scavenges reactive oxygenated species (ROS) formed during the UV-inducing oxidative stress on the skin. The amounts of melanin in the skin depend on the phototype. In most phenotypes, endogenous melanin is not enough for full protection, especially in the summertime. Thus, photoprotective molecules should be added to commercial sunscreens. These molecules should show UV-absorbing capacity to complement the intrinsic photoprotection of the cutaneous natural pigment. This review deals with (a) the use of exogenous melanin or melanin-related compounds to mimic endogenous melanin and (b) the use of a number of natural compounds from plants and marine organisms that can act as UV filters and ROS scavengers. These agents have antioxidant properties, but this feature usually is associated to skin-lightening action. In contrast, good photoprotectors would be able to enhance natural cutaneous pigmentation. This review examines flavonoids, one of the main groups of these agents, as well as new promising compounds with other chemical structures recently obtained from marine organisms.
Topics: Animals; Antioxidants; Aquatic Organisms; Flavonoids; Humans; Melanins; Oxidative Stress; Plants; Reactive Oxygen Species; Skin; Skin Pigmentation; Sunscreening Agents; Ultraviolet Rays
PubMed: 32230973
DOI: 10.3390/molecules25071537 -
Biomedicine & Pharmacotherapy =... Feb 2021Artificial sunscreens are already gaining traction in order to protect the skin from sunburns, photoaging and photocarcinogenesis. However, the efficacy and safety of... (Review)
Review
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.
Topics: Administration, Cutaneous; Animals; Antioxidants; Humans; Oxidative Stress; Plant Extracts; Plants, Medicinal; Skin; Skin Aging; Sunburn; Sunscreening Agents; Ultraviolet Rays
PubMed: 33360043
DOI: 10.1016/j.biopha.2020.111161 -
Journal of the American Academy of... May 2021Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic... (Review)
Review
Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.
Topics: Administration, Cutaneous; Administration, Oral; Erythema; Humans; Injections, Subcutaneous; Radiation-Protective Agents; Skin; Skin Pigmentation; Sunlight; Treatment Outcome; Ultraviolet Rays
PubMed: 33640513
DOI: 10.1016/j.jaad.2020.11.074 -
Photodermatology, Photoimmunology &... Nov 2022Melasma is a frequent photoexacerbated hyperpigmentary disorder, which can significantly impact on the quality of life. We sought to review the pathogenesis of melasma,... (Review)
Review
BACKGROUND/PURPOSE
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.
METHODS
We conducted a narrative review of the literature. We performed literature searches with PubMed from January 1990 to December 2021 using the keywords "melasma," "pathogenesis," "ultraviolet radiation," "visible light," "photoprotection," and "sunscreens."
RESULTS
The physiopathology of melasma includes a complex interaction between genetics, sex hormones, and sun exposure. Visible light, in particular high-energy visible light (HEVL), and long-wave UVA (UVA1) play a key role in melasma pathophysiology, and recent research suggests that melasma shares many features with photoaging disorders. Melasma disproportionately affects dark-skinned individuals. Some 30% to 50% of South Americans and Asians, among other ethnicities, can present with melasma. Dark-skinned patients take fewer photoprotective measures. Also, the majority of melasma patients do not adequately follow photoprotection recommendations, including the application of sunscreen. Intensive use of a broad-spectrum sunscreen can prevent melasma in high-risk individuals, can lessen melasma severity (associated or not with depigmenting agents), and can reduce relapses.
CONCLUSIONS
Due to the physiopathology of melasma, sunscreens should be broad-spectrum with high sun protection factor, and provide high protection against UVA1 and VL. Sunscreens should be cosmetically acceptable and leave no white residue. Tinted sunscreens are an excellent choice, as pigments can protect from HEVL and UVA1, and may provide camouflage, but they must offer colors that match the skin tone of each patient.
Topics: Humans; Sunscreening Agents; Ultraviolet Rays; Quality of Life; Sun Protection Factor; Melanosis; Skin
PubMed: 35229368
DOI: 10.1111/phpp.12783 -
International Journal of Molecular... Aug 2021The active metabolites of vitamin D (D) and lumisterol (L) exert a variety of antiaging and photoprotective effects on the skin. These are achieved through... (Review)
Review
The active metabolites of vitamin D (D) and lumisterol (L) exert a variety of antiaging and photoprotective effects on the skin. These are achieved through immunomodulation and include anti-inflammatory actions, regulation of keratinocytes proliferation, and differentiation programs to build the epidermal barrier necessary for maintaining skin homeostasis. In addition, they induce antioxidative responses, inhibit DNA damage and induce DNA repair mechanisms to attenuate premature skin aging and cancerogenesis. The mechanism of action would involve interaction with multiple nuclear receptors including VDR, AhR, LXR, reverse agonism on RORα and -γ, and nongenomic actions through 1,25D-MARRS receptor and interaction with the nongenomic binding site of the VDR. Therefore, active forms of vitamin D including its canonical (1,25(OH)D) and noncanonical (CYP11A1-intitated) D derivatives as well as L derivatives are promising agents for the prevention, attenuation, or treatment of premature skin aging. They could be administrated orally and/or topically. Other forms of parenteral application of vitamin D precursor should be considered to avoid its predominant metabolism to 25(OH)D that is not recognized by CYP11A1 enzyme. The efficacy of topically applied vitamin D and L derivatives needs further clinical evaluation in future trials.
Topics: Animals; Antioxidants; DNA Damage; Humans; Skin; Skin Aging; Vitamin D
PubMed: 34445803
DOI: 10.3390/ijms22169097 -
Dermatology Research and Practice 2014Zinc, both in elemental or in its salt forms, has been used as a therapeutic modality for centuries. Topical preparations like zinc oxide, calamine, or zinc pyrithione... (Review)
Review
Zinc, both in elemental or in its salt forms, has been used as a therapeutic modality for centuries. Topical preparations like zinc oxide, calamine, or zinc pyrithione have been in use as photoprotecting, soothing agents or as active ingredient of antidandruff shampoos. Its use has expanded manifold over the years for a number of dermatological conditions including infections (leishmaniasis, warts), inflammatory dermatoses (acne vulgaris, rosacea), pigmentary disorders (melasma), and neoplasias (basal cell carcinoma). Although the role of oral zinc is well-established in human zinc deficiency syndromes including acrodermatitis enteropathica, it is only in recent years that importance of zinc as a micronutrient essential for infant growth and development has been recognized. The paper reviews various dermatological uses of zinc.
PubMed: 25120566
DOI: 10.1155/2014/709152 -
The Journal of Clinical and Aesthetic... Jul 2017This review article details the main mechanisms of action and clinical applications of topical vitamin C on the skin, including its antioxidative, photoprotective,... (Review)
Review
This review article details the main mechanisms of action and clinical applications of topical vitamin C on the skin, including its antioxidative, photoprotective, antiaging, and antipigmentary effects. A PubMed search for the relevant articles on vitamin C and the skin was conducted using the following key words: "vitamin C," "ascorbic acid," "ascorbyl-6-palmitate,"and "magnesium ascorbyl phosphate." As one of the most powerful antioxidants in the skin, vitamin C has been shown to protect against photoaging, ultraviolet-induced immunosuppression, and photocarcinogenesis. It also has an antiaging effect by increasing collagen synthesis, stabilizing collagen fibers, and decreasing collagen degradation. It decreases melanin formation, thereby reducing pigmentation. Vitamin C is the primary replenisher of vitamin E and works synergistically with vitamin E in the protection against oxidative damage. Topical vitamin C has a wide range of clinical applications, from antiaging and antipigmentary to photoprotective. Currently, clinical studies on the efficacy of topical formulations of vitamin C remain limited, and the challenge lies in finding the most stable and permeable formulation in achieving the optimal results.
PubMed: 29104718
DOI: No ID Found -
Skin Therapy Letter May 2017A triad approach to the treatment of acne and rosacea has been recommended. This integrated management approach includes patient education, selection of therapeutic... (Review)
Review
A triad approach to the treatment of acne and rosacea has been recommended. This integrated management approach includes patient education, selection of therapeutic agents, and initiation of an appropriate skin care regime. Proper skin care in patients undergoing treatment of both acne and rosacea includes use of products formulated for sensitive skin that cleanse, moisturize and photoprotect the skin. Both acne and rosacea are associated with epidermal barrier dysfunction, which can be mitigated by suitable skin care practices. Appropriate skin care recommendations for patients with acne and rosacea will be discussed.
Topics: Acne Vulgaris; Humans; Rosacea; Skin Care
PubMed: 28492949
DOI: No ID Found -
Photochemistry and Photobiology 2008Human skin is repeatedly exposed to UVR that influences the function and survival of many cell types and is regarded as the main causative factor in the induction of... (Review)
Review
Human skin is repeatedly exposed to UVR that influences the function and survival of many cell types and is regarded as the main causative factor in the induction of skin cancer. It has been traditionally believed that skin pigmentation is the most important photoprotective factor, as melanin, besides functioning as a broadband UV absorbent, has antioxidant and radical scavenging properties. Besides, many epidemiological studies have shown a lower incidence for skin cancer in individuals with darker skin compared to those with fair skin. Skin pigmentation is of great cultural and cosmetic importance, yet the role of melanin in photoprotection is still controversial. This article outlines the major acute and chronic effects of UVR on human skin, the properties of melanin, the regulation of pigmentation and its effect on skin cancer prevention.
Topics: Humans; Melanins; Radiation-Protective Agents; Skin; Skin Neoplasms; Sunburn; Ultraviolet Rays
PubMed: 18435612
DOI: 10.1111/j.1751-1097.2007.00226.x