The chronic exposure of skin to ultraviolet (UV) radiation causes adverse dermal reactions, such as erythema, sunburn, photoaging, and cancer, by altering several signalling pathways associated with oxidative stress, inflammation, and DNA damage. One of the possible UV light protection strategies is the use of dermal photoprotective preparations. The plant hormone kinetin (N6-furfuryladenine; KIN) exhibits antioxidant and anti-senescent effects in human cells. Topically applied KIN also reduced some of the clinical signs of photodamaged skin. To improve the biological activities of KIN, several derivatives have been recently prepared and their beneficial effects on cell viability of skin cells exposed to UVA and UVB light were screened. Two potent candidates, 6-(tetrahydrofuran-2-yl)methylamino-9-(tetrahydrofuran-2-yl)purine (HEO) and 6-(thiophen-2-yl)methylamino-9-(tetrahydrofuran-2-yl)purine (HEO6), were identified. Here the effects of KIN, its N9-substituted derivatives the tetrahydropyran-2-yl derivative of KIN (THP), tetrahydrofuran-2-yl KIN (THF), HEO and HEO6 (both THF derivatives) on oxidative stress, apoptosis and inflammation in UVA- or UVB-exposed skin cell was investigated. Human primary dermal fibroblasts and human keratinocytes HaCaT pre-treated with the tested compounds were then exposed to UVA/UVB light using a solar simulator. All compounds effectively prevented UVA-induced ROS generation and glutathione depletion in both cells. HEO6 was found to be the most potent. All compounds also reduced UVB-induced caspase-3 activity and interleukin-6 release. THP and THF exhibited the best UVB protection. In conclusion, our results demonstrated the UVA- and UVB-photoprotective potential of KIN and its derivatives. From this point of view, they seem to be useful agents for full UV spectrum protective dermatological preparations.
- MeSH
- antioxidancia farmakologie MeSH
- keratinocyty * metabolismus MeSH
- kinetin metabolismus farmakologie MeSH
- kůže * účinky záření MeSH
- lidé MeSH
- ultrafialové záření škodlivé účinky MeSH
- zánět metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The ultraviolet (UV) part of solar radiation can permanently affect skin tissue. UVA photons represent the most abundant UV component and stimulate the formation of intracellular reactive oxygen species (ROS), leading to oxidative damage to various biomolecules. Several plant-derived polyphenols are known as effective photoprotective agents. This study evaluated the potential of quercetin (QE) and its structurally related flavonoid taxifolin (TA) to reduce UVA-caused damage to human primary dermal fibroblasts (NHDF) and epidermal keratinocytes (NHEK) obtained from identical donors. Cells pre-treated with QE or TA (1 h) were then exposed to UVA light using a solar simulator. Both flavonoids effectively prevented oxidative damage, such as ROS generation, glutathione depletion, single-strand breaks formation and caspase-3 activation in NHDF. These protective effects were accompanied by stimulation of Nrf2 nuclear translocation, found in non-irradiated and irradiated NHDF and NHEK, and expression of antioxidant proteins, such as heme oxygenase-1, NAD(P)H:quinone oxidoreductase 1 and catalase. For most parameters, QE was more potent than TA. On the other hand, TA demonstrated protection within the whole concentration range, while QE lost its protective ability at the highest concentration tested (75 μM), suggesting its pro-oxidative potential. In summary, QE and TA demonstrated UVA-protective properties in NHEK and NHDF obtained from identical donors. However, due to the in vitro phototoxic potential of QE, published elsewhere and discussed herein, further studies are needed to evaluate QE safety in dermatological application for humans as well as to confirm our results on human skin ex vivo and in clinical trials.
- MeSH
- fibroblasty MeSH
- flavonoidy * metabolismus MeSH
- keratinocyty MeSH
- kůže metabolismus MeSH
- lidé MeSH
- oxidační stres MeSH
- quercetin * analogy a deriváty farmakologie MeSH
- ultrafialové záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: Excessive exposure of skin to solar radiation is associated with greatly increased production of reactive oxygen and nitrogen species (ROS, RNS) resulting in oxidative stress (OS), inflammation, immunosuppression, the production of matrix metalloproteinase, DNA damage and mutations. These events lead to increased incidence of various skin disorders including photoaing and both non-melanoma and melanoma skin cancers. The ultraviolet (UV) part of sunlight, in particular, is responsible for structural and cellular changes across the different layers of the skin. Among other effects, UV photons stimulate oxidative damage to biomolecules via the generation of unstable and highly reactive compounds. In response to oxidative damage, cytoprotective pathways are triggered. One of these is the pathway driven by the nuclear factor erythroid-2 related factor 2 (Nrf2). This transcription factor translocates to the nucleus and drives the expression of numerous genes, among them various detoxifying and antioxidant enzymes. Several studies concerning the effects of UV radiation on Nrf2 activation have been published, but different UV wavelengths, skin cells or tissues and incubation periods were used in the experiments that complicate the evaluation of UV radiation effects. CONCLUSIONS: This review summarizes the effects of UVB (280-315 nm) and UVA (315-400 nm) radiation on the Nrf2 signaling pathway in dermal fibroblasts and epidermal keratinocytes and melanocytes. The effects of natural compounds (pure compounds or mixtures) on Nrf2 activation and level as well as on Nrf2-driven genes in UV irradiated human skin fibroblasts, keratinocytes and melanocytes are briefly mentioned as well.HighlightsUVB radiation is a rather poor activator of the Nrf2-driven pathway in fibroblastsUVA radiation stimulates Nrf2 activation in dermal fibroblastsEffects of UVA on the Nrf2 pathway in keratinocytes and melanocytes remain unclearLong-term Nrf2 activation in keratinocytes disturbs their normal differentiationPharmacological activation of Nrf2 in the skin needs to be performed carefully.
- MeSH
- faktor 2 související s NF-E2 metabolismus MeSH
- keratinocyty MeSH
- kůže metabolismus MeSH
- lidé MeSH
- reaktivní formy kyslíku MeSH
- signální transdukce * MeSH
- transkripční faktor GABP MeSH
- ultrafialové záření * škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The harmful effects of low energy UVA photons (315-400 nm) are associated with the massive production of reactive oxygen species resulting in oxidative stress. In response to oxidative damage, NF-E2-related factor 2 (Nrf2) is translocated to the nucleus and drives the expression of detoxication and antioxidant enzymes. UVA's effect on Nrf2 has been quite well characterised in dermal fibroblasts. However, there is a dearth of such information for keratinocytes. This study aimed to evaluate and compare the effect of UVA radiation on the Nrf2 pathway and oxidative stress related proteins in primary human dermal fibroblasts (NHDF), epidermal keratinocytes (NHEK) and human keratinocyte cell line HaCaT. NHDF were exposed to doses of 2.5-7.5 J/cm2, NHEK and HaCaT to 10-20 J/cm2 using a solar simulator. Effects on Nrf2 translocation were evaluated after 1, 3 and 6 h and Nrf2-controlled proteins (heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione reductase (GSR), glutathione-S-transferase (GST), interleukine-6 (IL-6), and matrix metalloproteinases (MMP-1, MMP-2)) after 3, 6 and 24 h. The results showed the fastest Nrf2 translocation was in UVA-irradiated HaCaT (1 h), persisting until the subsequent time interval (3 h), while in primary keratinocytes the effect of radiation was minimal. In NHDF, UVA-stimulated Nrf2 translocation was conspicuous 3 h after UVA treatment. In NHDF, most of the studied proteins (NQO1, HO-1, GSR, GSTM1 and MMP-1) showed the highest level 24 h after UVA exposure, except for MMP-2 and IL-6 which had their highest level at a shorter time incubation interval (3 h). In NHEK, NQO1, HO-1 and GST were increased 6 h after UVA exposure, GSR and MMP-2 level was slightly below or above the control level, and MMP-1 and IL-6 increased at shorter time intervals. When comparing NHEK and HaCaT, these cells displayed contrary responses in most of the Nrf2-controlled proteins. Thus, primary keratinocytes cannot be replaced with HaCaT when studying cell signalling such as the Nrf2 driven pathway and Nrf2-controlled proteins.
- MeSH
- faktor 2 související s NF-E2 metabolismus MeSH
- keratinocyty metabolismus účinky záření MeSH
- kultivované buňky MeSH
- kůže cytologie metabolismus účinky záření MeSH
- lidé MeSH
- signální transdukce účinky záření MeSH
- transport proteinů MeSH
- ultrafialové záření * MeSH
- viabilita buněk účinky záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Chronic exposure to solar radiation is related to an increased incidence of various skin disorders, including premature skin aging and melanoma and non-melanoma skin cancers. Ultraviolet (UV) photons in particular are responsible for skin damage. Solar UV photons mainly belong to UVA wavebands, however UVA radiation has been mostly ignored for a long time. At the cellular level, UVA photons mainly provoke indirect oxidative damage to biomolecules via the massive generation of unstable and highly reactive compounds. Human skin has several effective mechanisms that forestall, repair and eliminate damage caused by solar radiation. Regardless, some damage persists and can accumulate with chronic exposure. Therefore, conscious protection against solar radiation (UVB+UVA) is necessary. Besides traditional types of photoprotection such as sunscreen use, new strategies are being searched for and developed. One very popular protective strategy is the application of phytochemicals as active ingredients of photoprotection preparations instead of synthetic chemicals. Phytochemicals usually possess additional biological activities besides absorbing the energy of photons, and those properties (e.g. antioxidant, anti-inflammatory) magnify the protective potential of phytochemicals and extracts. Therefore, compounds of natural origin are in the interest of researchers as well as developers. In this review, only studies on UVA protection with well-documented experimental conditions are summarized. This article includes 17 well standardized plant extracts (Camellia sinensis (L.) Kuntze, Silybum marianum L. Gaertn., Punica granatum L., Polypodium aureum L., Vaccinium myrtillus L., Lonicera caerulea L., Thymus vulgaris L., Opuntia ficus-indica (L.) Mill., Morinda citrifolia L., Aloe vera (L.) Burm.f., Oenothera paradoxa Hudziok, Galinsoga parviflora Cav., Galinsoga quadriradiata Ruiz et Pavón, Hippophae rhamnoides L., Cola acuminata Schott & Endl., Theobroma cacao L. and Amaranthus cruentus L.) and 26 phytochemicals.
The exposure of naked unprotected skin to solar radiation may result in numerous acute and chronic undesirable effects. Evidence suggests that silymarin, a standardized extract from Silybum marianum (L.) Gaertn. seeds, and its major component silybin suppress UVB-induced skin damage. Here, we aimed to investigate the UVA-protective effects of silymarin's less abundant flavonolignans, specifically isosilybin (ISB), silychristin (SC), silydianin (SD), and 2,3-dehydrosilybin (DHSB). Normal human dermal fibroblasts (NHDF) pre-treated for 1 h with flavonolignans were then exposed to UVA light using a solar simulator. Their effects on reactive oxygen species (ROS), carbonylated proteins and glutathione (GSH) level, caspase-3 activity, single-strand breaks' (SSBs) formation and protein level of matrix metalloproteinase-1 (MMP-1), heme oxygenase-1 (HO-1), and heat shock protein (HSP70) were evaluated. The most pronounced preventative potential was found for DHSB, a minor component of silymarin, and SC, the second most abundant flavonolignan in silymarin. They had significant effects on most of the studied parameters. Meanwhile, a photoprotective effect of SC was mostly found at double the concentration of DHSB. ISB and SD protected against GSH depletion, the generation of ROS, carbonylated proteins and SSBs, and caspase-3 activation, but had no significant effect on MMP-1, HO-1, or HSP70. In summary, DHSB and to a lesser extent other silymarin flavonolignans are potent UVA-protective compounds. However, due to the in vitro phototoxic potential of DHSB published elsewhere, further studies are needed to exclude phototoxicity for humans as well as to confirm our results on human skin ex vivo and in vivo.
- MeSH
- cytoprotekce účinky léků MeSH
- fibroblasty účinky léků účinky záření MeSH
- glutathion metabolismus MeSH
- hemoxygenasa-1 metabolismus MeSH
- jednořetězcové zlomy DNA účinky záření MeSH
- karbonylace proteinů účinky záření MeSH
- kaspasa 3 metabolismus MeSH
- kultivované buňky MeSH
- kůže účinky záření MeSH
- lidé MeSH
- matrixová metaloproteinasa 1 metabolismus MeSH
- přípravky chránící proti slunci farmakologie MeSH
- proteiny tepelného šoku HSP70 metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- silymarin analogy a deriváty farmakologie MeSH
- ultrafialové záření škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Silybum marianum (L.) is a medicinal plant traditionally used in treatment of liver disorders. In last decades, silymarin (SM), a standardized extract from S. marianum seeds has been studied for its dermatological application, namely for UVB-protective properties. However, information on SM and its polyphenols effect on activity of enzymes participating in the (photo)aging process is limited. Therefore, evaluation of SM and its flavonolignans potential to inhibit collagenase, elastase, and hyaluronidase in tube tests was the goal of this study. The antioxidant and UV screening properties of SM and its flavonolignans silybin, isosilybin, silydianin, silychristin and 2,3-dehydrosilybin (DHSB) were also evaluated by a DPPH assay and spectrophotometrical measurement. DHSB showed the highest ability to scavenge DPPH radical and also revealed the highest UVA protection factor (PF-UVA) that corresponds with its absorption spectrum. SM and studied flavonolignans were found to exhibit anti-collagenase and anti-elastase activity. The most potent flavonolignan was DHSB. None of studied flavonolignans or SM showed anti-hyaluronidase activity. Our results suggest that SM and its flavonolignans may be useful agents for skin protection against the harmful effects of full-spectrum solar radiation including slowing down skin (photo)aging.
- MeSH
- antioxidancia chemie izolace a purifikace MeSH
- flavonolignany chemie izolace a purifikace MeSH
- kůže účinky léků patologie účinky záření MeSH
- lidé MeSH
- ostropestřec mariánský chemie MeSH
- rostlinné extrakty chemie MeSH
- semena rostlinná chemie MeSH
- silymarin chemie izolace a purifikace MeSH
- ultrafialové záření škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Human skin explant (HSE) seems to be a useful model for dermatological/cosmetic testing. HSE prepared from donor superfluous skin from plastic surgery operations is cheap and easily obtainable compared to reconstructed models. The HSE use, however, may be limited by the degeneration processes during cultivation. The aim was to monitor changes in metabolic activity and selected apoptotic, inflammatory and antioxidant parameters during 7 day cultivation. The significant changes were found in the superoxide dismutase-2 level from day 5, glutathione S-reductase level from day 6, metabolic activity and fibulin-5 level from day 4, cyclooxygenase-2, interleukin-6 and interleukin-10 from day 1 to 2. Other selected markers (lipid peroxidation products and glutathione level, glutathione S-transferase, catalase, superoxide dismutase and glutathione S-reductase activity, glutathione peroxidase and glutathione S-reductase levels) were not modified significantly due to high inter-individual variability of skin donors. The HSE microstructure as well as cytokeratin-10 and proliferation marker Ki67 expression was also only minimally affected during cultivation. Collectively, the results demonstrate that HSE represents a good model for short-term studies focused on the physical and chemical agent toxicity, protective potential of compounds or metabolic biotransformation. However, reduced metabolic activity, increased inflammation and the high inter-individual variability and sensitivity of donors have to be taken into consideration.
- MeSH
- antioxidancia metabolismus MeSH
- biologické markery metabolismus MeSH
- biologické modely MeSH
- časové faktory MeSH
- cyklooxygenasa 2 metabolismus MeSH
- glutathionperoxidasa metabolismus MeSH
- glutathionreduktasa metabolismus MeSH
- interleukin-6 metabolismus MeSH
- kůže * imunologie metabolismus patologie MeSH
- lidé MeSH
- superoxiddismutasa metabolismus MeSH
- techniky tkáňových kultur metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
UV záření (UVA a UVB), které je složkou slunečního světla dopadajícího na zemský povrch, má vysokou energii. Díky této skutečnosti může přímo reagovat s biomolekulami (DNA, lipidy nebo proteiny), případně vyvolávat tvorbu reaktivních forem kyslíku (ROS), které mohou tyto biomolekuly poškozovat, což se projeví nevratnými změnami kůže vedoucími k jejímu předčasnému stárnutí, v horším případě ke karcinogenezi. Ve snaze potlačit nežádoucí účinky slunečního záření se využívají různé přístupy ochrany kůže. Kromě anorganických a organických UV filtrů jsou zkoumány přirozeně se vyskytující nízkomolekulární látky rostlinné povahy, které mohou eliminovat nežádoucí účinky slunečního záření. Rostlinné hormony cytokininy, zejména kinetin (Kin), který je N6-substituovaným derivátem adeninu, jsou známy pro svou schopnost zpomalovat přirozené stárnutí buněk, to znamená, že vykazují tzv. antisenescenční vlastnosti. Nedávno bylo prokázáno, že některé cytokininy a jejich deriváty mají ochranné vlastnosti vůči UVA i UVB záření. Jejich využití při zpomalení předčasného stárnutí kůže působením slunečního záření je předmětem intenzivního studia.
UV radiation (UVA and UVB), is an integral part of the sunlight reaching the earth's surface containing high energy photons. Owning to the high energy, the photons they can directly interact with biomolecules like DNA, lipids, and proteins and/or generate reactive oxygen species (ROS) causing oxidative damage and irreversible changes in the skin. The changes can lead to premature skin ageing (photoageing) and even skin cancer. Adequate protection of the skin is hence of paramount importance. Exogenous protection approaches that are being developed include organic and inorganic sunscreens as well as various naturally occurring low molecular weight compounds of plant-origin. The plant hormones, cytokinins, especially kinetin (Kin), which is a N6-substituted adenine derivative, are known for their antisenescence and antioxidant effects. Some cytokinins and their derivatives, in addition, have been shown to have photoprotective properties against UVA and UVB radiation. Their application in the prevention of photoageing is being intensively studied.
