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The human skin, as the boundary organ between the human body and the environment, is under the constant influence of free radicals (FR), both from the outside in and from the inside out. Carotenoids are known to be powerful antioxidant substances playing an essential role in the reactions of neutralization of FR (mainly reactive oxygen species ROS). Carotenoid molecules present in the tissue are capable of neutralizing several attacks of FR, especially ROS, and are then destroyed. Human skin contains carotenoids, such as α-, γ-, β-carotene, lutein, zeaxanthin, lycopene and their isomers, which serve the living cells as a protection against oxidation. Recent studies have reported the possibility to investigate carotenoids in human skin quickly and non-invasively by spectroscopic means. Results obtained from in-vivo studies on human skin have shown that carotenoids are vital components of the antioxidative protective system of the human skin and could serve as marker substances for the overall antioxidative status. Reflecting the nutritional and stress situation of volunteers, carotenoids must be administered by means of antioxidant-rich products, e.g., in the form of fruit and vegetables. Carotenoids are degraded by stress factors of any type, inter alia, sun radiation, contact with environmental hazards, illness, etc. The kinetics of the accumulation and degradation of carotenoids in the skin have been investigated. [ABSTRACT FROM AUTHOR]

Carotenoids are important substances for human skin due to their powerful antioxidant properties in reaction of neutralization of free radicals and especially reactive oxygen species, including singlet oxygen. Concentration of carotenoids in the skin could mirror the current redox status of the skin and should be investigated in vivo. Optical methods are ideally suited for determination of carotenoids in mammalian skin in vivo as they are both noninvasive and quick. Four different optical methods could be used for in vivo measurement of carotenoids in the human or animal skin: (1) resonance Raman spectroscopy; (2) Raman microscopy; (3) reflection spectroscopy; (4) skin color measurements. The advantages, shortcomings, and limitations of the above-mentioned optical methods are discussed. [ABSTRACT FROM AUTHOR]

The interaction of free radicals with antioxidants is a topic of increasing interest in the development of prevention strategies against skin ageing. Carotenoids can serve as marker substances for the complete antioxidative network of human skin. Recently, it has become possible to measure the carotenoids non-invasively and online using resonance Raman spectroscopy. This method has been used in various studies to investigate the interaction of carotenoid antioxidants and free radicals in human skin. In this review, the results of the selected studies are summarized and compared. It could be demonstrated that the carotenoid concentration of the skin reflects the lifestyle of individuals. A high level of carotenoids can be achieved with a healthy diet rich, for instance, in fruit and vegetables. Stress factors such as illness, UV and IR radiation of the sun, and smoking and alcohol consumption reduce the concentration of the carotenoids in the skin. It could be demonstrated that premature skin ageing was less in people with a high level of antioxidants in their tissue. Consequently, the furrows and wrinkles were not so deep and dense as in the skin of individuals with a low antioxidant level. The measurements are highly suited for the development of anti-ageing strategies and can be efficiently used in the medical diagnostics and therapy control. [ABSTRACT FROM AUTHOR]

Background: The formation of free radicals in human skin by solar ultraviolet radiation is considered to be the main reason for extrinsic skin aging. The antioxidants in human tissue represent an efficient protection system against the destructive action of these reactive free radicals. In this study, the parameters of the skin, epidermal thickness, stratum corneum moisture, elasticity and wrinkle volume, were determined before and after the treatment with antioxidant- or placebo-containing tablets and creams. Methods: The study included 5 groups of 15 volunteers each, who were treated for 2 months with antioxidant-containing or placebo tablets, creams or a combination of antioxidant-containing tablets and cream. The skin parameters were measured at time point 0 and at week 8 utilizing ultrasound for the determination of epidermal thickness, a corneometer for stratum corneum moisture measurements, skin profilometry for quantifying the wrinkle volume and a cutometer for determining the elasticity. Results: The verum cream had a positive influence on epidermal thickness, elasticity and skin moisture, but the verum tablets improved the epidermal thickness only. The combined application of verum tablets and creams led to a significant improvement of all investigated skin parameters, whereas the application of placebo tablets or cream did not influence any parameters. Conclusion: The topical and oral supplementation of antioxidants can be an instrument to improve several skin parameters and potentially counteract or decelerate the process of extrinsic skin aging. © 2016 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The antioxidant status of the human skin provides protection against the destructive action of free radicals. Most antioxidants cannot be synthesized by the human organism itself, but have to be ingested with a healthy nutrition rich in fruit and vegetables. The Korean cuisine is known to be one of the healthiest worldwide. This binational study investigated the cutaneous carotenoid concentrations in German subjects, South Korean subjects and immigrant Korean subjects resident in Germany and examined whether dietary- and lifestyle-related differences are reflected in the cutaneous carotenoid concentrations. Methods: Measurements of the carotenoid concentrations of 714 healthy volunteers were performed using a non-invasive spectroscopic measurement system based on reflectance spectroscopy. Results: In the present study South Korean residents showed a significantly higher antioxidant status than both native German residents and Korean immigrants living in Germany (p < 0.001). The first generation of Korean immigrants to Germany over the age of 50 mostly preserved Korean dietary habits, showing significantly higher concentrations (p < 0.001) than the German-born second and third Korean generations under the age of 50. Conclusion: The results of the study indicate that a healthy nutrition alone does not provide a high antioxidant status unless the stress exposure can be reduced simultaneously. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims: The palmoplantar erythrodysaesthesia (PPE) is an inflammatory cutaneous side effect in patients under chemotherapy with pegylated liposomal doxorubicin (PLD), with indications that also other chemotherapeutics induce similar side effects. Recently, it has been demonstrated that PLD escapes with the sweat onto the skin inducing radical-forming processes that damage the skin. The topical application of antioxidants with a high radical protection factor has proven to be a very efficient prevention strategy for PLD-treated patients. Methods: 68 patients, who had been treated with 12 different chemotherapeutics and experienced side effects similar to PPE, were treated with a meanwhile commercially available ointment. Results: At the beginning of the therapy, 46 patients suffered from a PPE of severity grade III, while in 22 patients a PPE of severity grade II was diagnosed. The application of the ointment resulted in a significant improvement of the clinical symptoms and the skin status in all these patients; their chemotherapies could be continued. Conclusion: The obtained results suggest that radical-forming processes play an essential role in a great number of chemotherapeutics which induce dermal side effects. The topical application of the antioxidant-containing ointment proved to be a good therapeutic option which needs further evaluation. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Pegylated liposomal doxorubicin (PLD) is a highly efficient chemotherapeutic; however, it induces dermal side effects such as palmar-plantar erythrodysesthesia (PPE) in up to 80% of cases, probably by being emitted with the sweat onto the skin surface. Aim: The aim of the present study was to examine whether a topically applied ointment containing antioxidants with a high radical protection factor is able to prevent the formation of PPE. Methods: Twenty patients suffering from ovarian carcinoma and treated with PLD were observed. Results: 60% of the patients tolerated the regular application of the cream and developed no PPE. The remaining 40% interrupted the application. Six of them developed PPE and resumed ointment application thereafter. In these cases the PPE disappeared or was strongly reduced. Conclusion: The results of the observation clearly demonstrate that topical application of the ointment is an efficient strategy against the development of PPE during chemotherapy with PLD. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Background: High doses of sun-emitted UV-radiation induce reactive oxygen species (ROS) as major pro-oxidants thus inducing premature skin aging. The best prevention of the destructive action of free radicals in human skin is textile coverings, topical sunscreens and the development of a high antioxidative protective network. Objective: The effects of topical, systemic and combined application of antioxidants (AO) were investigated on human skin in vivo. Methods: Topical application of creams and systemic incorporation of tablets both containing AO was investigated in vivo by resonance Raman spectroscopy. Results: Topical, systemic and combined AO-treatments induced a statistically significant increase of AO levels in human skin while placebo did not show any changes. The highest accumulation was induced by the combination of topical and systemic AO. Carotenoid-tablets combined with placebo-cream induced less carotenoid accumulation than carotenoid-tablets alone. Carotenoid levelling after the end of treatment lasted for around 2weeks following the topical application of AOs, and up to 5weeks after systemic administration, depending on the BMI of volunteers. Conclusion: Topically applied AO are stored in the SC for a short time only due to the rapid AO-depletion by desquamation, textile contact, washing and environmental stress. In contrast to topical application, the systemically applied carotenoids are stored in the body fat tissue and slowly released onto the skin surface with sweat and sebum. The combined topical and systemic application of AO represents an optimal form of protection of the AO-network. [Copyright &y& Elsevier]

The influence of stress factors on human skin induces the production of free radicals. Free radicals react immediately with antioxidants contained in the skin, giving rise to their depletion and with the surrounding molecules, resulting in their damage, disorganization and even destruction. High amounts of free radicals are produced in the upper skin layers, i.e. mainly in the epidermis, subsequent to sun irradiation. Irradiation of the skin in the infra-red (IR) range of the spectra, applied at physiological doses, can produce free radicals. The magnitude of destruction of antioxidants, such as carotenoids, can serve as a marker of the extent of the stress factor, characterized by the quantity of produced free radicals. In this study, measurements on the degradation of cutaneous carotenoids following IR skin irradiation of 12 healthy volunteers (skin type II), with two IR sources (standard infrared radiator = SIR and water filter infrared = wIRA) were taken using resonance Raman spectroscopy. Topical application of the antioxidant beta-carotene (2 mg/cm) provided protection for the human skin when exposed to IR radiation. The magnitude of the degradation of dermal carotenoids after IR irradiation was significantly higher for SIR than for wIRA irradiation, for both non-treated and cream-treated skin areas. The amount of destroyed carotenoids after IR irradiation was higher in the case of pretreatment with beta-carotene than for the untreated skin, indicating that the superficial part of antioxidants is most important for protecting against external stressors. The direct comparison of beta-carotene content was significantly higher for the cream-treated compared to untreated areas for all pairs: baseline, wIRA, after wIRA, baseline SIR and after SIR. Additionally, topically applied carotenoids as a single antioxidant component are less stable than the carotenoids in the skin incorporated by nutrition and accumulated in a mixture with different antioxidant substances. Resonance Raman spectroscopy can be used for the non-invasive measurements of carotenoids, which can be rated as marker substances of redox processes. [ABSTRACT FROM AUTHOR]

Background: The cutaneous antioxidants form an efficient protection system against the destructive potential of free radicals, produced by environmental factors, such as UV-sun irradiation, hazardous substances and lifestyle habits. Most of the antioxidants cannot be produced by the human organism. Thus, they have to be incorporated by food and beverages. Material and Methods: In the present manuscript, the distribution of carotenoids as a marker for antioxidative potential in human skin was investigated with two different in vivo Raman spectroscopy methods with an excitation wavelength of 785 nm (Skin Analyzer) and at 488 nm (resonance Raman spectroscopy). The carotenoid profile was assessed at three different anatomical locations (palm, forehead and volar forearm) in 12 healthy volunteers. Results: In untreated skin, the major fraction of the carotenoids is located in the upper part of the stratum corneum (SC). The amount of carotenoid is lower in the upper part of the SC on the forearm compared to forehead and palm shown with both methods. Both methods detect similar distinction patterns of carotenoid levels for the three anatomical locations. Conclusion: The present study supports the hypothesis that antioxidative substances; here carotenoids, are secreted via eccrine sweat glands and/or sebaceous glands to the skin surface. Raman spectroscopic methods are an efficient tool to analyze the distribution of carotenoids in the human skin over time and with the Skin Analyzer over different layers of the epidermis. Resonance Raman spectroscopy is suited to analyze deeper parts of the skin. [ABSTRACT FROM AUTHOR]

Abstract: Carotenoids, naturally occurring lipophilic micronutrients, possess an antioxidant activity associated with protection from damage induced by free radicals. The present study investigated an innovative non-invasive method to measure cutaneous levels of lycopene and β-carotene and to monitor the distribution of orally administered lactolycopene in human skin and plasma. A double-blind placebo-controlled randomized study was performed in 25 volunteers, who were under a lycopene-deprived diet (4weeks prior to study until end of the study) and orally received either lactolycopene or placebo for 12weeks. Skin and plasma levels of lycopene and β-carotene were monitored monthly using Raman spectroscopy and HPLC, respectively. Cutaneous levels of lycopene and β-carotene monitored by resonance Raman spectroscopy showed high reliability. Irrespective of the investigated area, cutaneous levels were sensitive to lycopene deprivation and to oral supplementation; the forehead showed the closest correlation to lycopene variation in plasma. Plasma and skin levels of lycopene were both sensitive to oral intake of lactolycopene and, interestingly, also skin levels of β-carotene. Thus, oral supplementation with lycopene led to an enrichment of β-carotene in human skin, possibly due to the fact that carotenoids act in the skin as protection chains, with a natural protection against free radicals. [Copyright &y& Elsevier]

Abstract: Antioxidant substances in the skin are expected to slow down photo ageing. We therefore developed the hypothesis that high levels of antioxidant substances may be correlated to lower levels of skin roughness. By utilizing modern optical non-invasive in vivo methods, the structures of the furrows and wrinkles as well as the concentration of lycopene were analyzed quantitatively on the forehead skin of 20 volunteers aged between 40 and 50 years. In a first step, the age of the volunteers was correlated to their skin roughness. Here, no significant correlation was found. In a second step, a significant correlation was obtained between the skin roughness and the lycopene concentration (R =0.843). These findings indicate that higher levels of antioxidants in the skin effectively lead to lower levels of skin roughness, and therefore support our hypothesis. [Copyright &y& Elsevier]