Article
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Context: Based on its antioxidant activity, melatonin was recently found to have a protection effect against photocarcinogenesis. Objective: This work aimed to develop an innovative sunscreen formulation based on the Pickering emulsions concept, stabilized by physical UV filters, modified starch and natural oils associated to melatonin as a key strategy for prevention against UV-induced skin damage. Materials and methods: For this purpose, melatonin was incorporated in Pickering emulsions that were characterized using physicochemical, in vitro and in vivo testing. Physicochemical studies included physical and chemical stability by a thorough pharmaceutical control. The possible protective effects of melatonin against UV-induced cell damage in HaCaT cell lines were investigated in vitro. The safety assessment and the in vivo biological properties of the final formulations, including Human Repeat Insult Patch Test and sunscreen water resistance tests were also evaluated. Results and discussion: These studies demonstrated that melatonin sunscreen Pickering emulsion was beneficial and presented a powerful protection against UVB-induced damage in HaCat cells, including inhibition of apoptosis. The inclusion of zinc oxide, titanium dioxide, green coffee oil and starch ensured a high SPF (50+) against UVA and UVB. Conclusion: The combination of melatonin, multifunctional solid particles and green coffee oil, contributed to achieve a stable, effective and innovative sunscreen with a meaningful synergistic protection against oxidative stress.

No full-text available

Request Full-text Paper PDF

Request the article directly
from the authors on ResearchGate.

... On one hand, it is especially preferred by people with a high propensity for skin irritation, and on the other hand, TiO 2 is necessary for manufacturing sunscreens with high sun protection factor (SPF). [53] Therefore, TiO 2 can be used as a solid particle for stabilization of Pickering emulsions, merging both stability and SPF properties for the sunscreen formulation ( Figure 2). [54] The studied performed by Marto et al. [55] arose from the necessity to fill a gap in photoprotective formulation research whose attention is frequently more focused on cosmetic issues rather than maximum protection against both UVA and B radiations as well as cellular protection. Thus, a novel Pickering emulsion sunscreen stabilized by TiO 2 (triethoxycaprylylsilane titanium dioxide) with a high UVB/A protection, biological activity, and better tolerability was designed to stabilize and deliver melatonin. ...
... The amount of melatonin extracted from the SC was significantly higher than from epidermis and dermis. [55] This is a mandatory outcome, as the target activity of sunscreens remains in the outermost layer of the skin, reflecting UV radiation and avoiding penetration to deeper viable skin layers ( Figure 3). All results revealed an excellent compromise between stability, UV protection, topical delivery, efficacy, safety, and cosmeticity. ...
... Thus, these results highlighted that melatonin-containing Pickering emulsion sunscreens could be one of the most promising segments in the personal-care industry. [55] Daniels et al. [56] proposed to determine the effect of different surface-modified TiO 2 on the type and the stability of topical Pickering emulsions. The emulsions contained TiO 2 particles, medium chain triglycerides, and water. ...
Article
Introduction: Topical drug delivery is a challenging area with many advantages such as avoidance of first passage effect, stabilization of blood concentrations and attainment of local therapeutic effect with fewer side effects. Despite all these advantages, topical drug delivery remains limited to few molecules, since skin acts as a barrier to the delivery of many therapeutic molecules. To overcome this obstacle, a favored strategy relies on selecting suitable vehicles for dermatologic therapy, such as emulsions, gels and, more recently, nanoparticulate systems. Areas covered: Particle-stabilized emulsions, also known as Pickering emulsions, have garnered interest in recent years. Although most of the investigation on Pickering emulsions has been based on model systems with inorganic or organic solid particles, recent advances have been made regarding the application of nanocarriers, protein-based particles or cyclodextrins for this purpose. This review reports the latest advances in Pickering emulsions technical challenges, and discusses the potential benefits and drawbacks of using these formulations for topical pharmaceutical and cosmetic applications as an alternative to conventional surfactant-based systems. Expert opinion: Pickering emulsions appear as a multifunctional dosage form with endless advantages. A great deal of progress is expected in this area, which might represent a renewed vision for the pharmaceutical and cosmetic industry.
... The cytotoxicity of rice water was evaluated using general cell viability endpoint MTT reduction and it was performed according to a previous reported work [17]. Cell viability was assessed after 24 h of incubation of a spontaneously immortalized human keratinocyte cell line HaCaT (CLS, Eppelheim, Germany) with different dilutions (up to 1:100) of rice water. ...
... The capacity of rice water to reduce the ROS production was evaluated through a fluorimeter technique that uses 2,7' dichlorodihydrofluorescein diacetate (H2-DCFDA) to quantify the intracellular ROS production, according to the method described elsewhere [17]. Briefly, for this measurement, HaCaT sub-confluent cells grown in 96-well plates, which were incubated for 30 min with 20 µM of H2-DCFDA in the dark, at 37 • C, were used. ...
... The compatibility evaluation study was performed on RWG, using the Marzulli and Maibach method [19]. Human Repeat Insult Patch Test (HRIPT) protocol, as described in detail elsewhere [17], was performed to evaluate the RWG irritant capacity. This protocol was approved by the local Ethical Committee and respected the Helsinki Declaration and the French Agency for the Safety of Health Products regulations on performed HRIPT studies on cosmetic products. ...
Article
Full-text available
The skin healing benefits of rice have been known for centuries. Rice (Oryza sativa) water is a food processing waste that can potentially be incorporated into cosmetic formulations. However, no scientific evidence supports their role in skincare products. The aim of this project is to design and develop a topical gel formulation containing rice water and to evaluate its biological properties, namely, the anti-aging and antioxidant rice water properties. Rice water was evaluated in terms of physico-chemical composition and in terms of in vitro biological antioxidant activity and elastase inhibitory effect. Rice water was incorporated into a hydrogel and the developed formulation was subjected to pharmacotechnical tests such as pH and viscosity. Biological and sensory effects were evaluated on a panel of 12 volunteers for 28 days. The safety evaluation study was performed on rice water gel, using the Human Repeat Insult Patch test protocol. Rice water presented in vitro biological antioxidant activity and elastase inhibitory effect. The gel formulation containing 96% rice water was biocompatible with the human skin and presented suitable cosmetic properties. Rice water should be thus considered as an anti-aging ingredient to be used as raw material for skincare applications.
... In vitro skin permeation and retention. In vitro permeation studies were performed according to literature [24]. The skin permeation of StNC-ER143 and ER143 solution (0.2 to 0.4 g of formulation, containing 111 µg/mL of ER143) was measured using Franz diffusion cells and newborn pig skin obtained from a local slaughterhouse. ...
... In vitro skin retention. In vitro skin retention study was performed using the tape stripping method recommended by OECD Guideline 428 and described elsewhere [24][25][26]. Briefly, the StNC-ER143 and ER143 solution (0.2 to 0.4 g of formulation, containing 111 µg/mL of ER143), were spread over the newborn pig skin (1 cm 2 ) in contact with 4 ml of receptor phase as described before. ...
Article
Psoriasis and atopic dermatitis patients show an excessive amount of elastase in peripheral blood neutrophils due to an imbalance between this proteolytic enzyme and its endogenous inhibitors, the search for new human neutrophil elastase (HNE) inhibitors are required. The HNE is an attractive therapeutic target and inhibitors with new molecular architectures have been extensively investigated. In this context a promising novel synthetic human neutrophil elastase inhibitor (ER143) was associated to a starch-based nanoparticulate system (StNC) with improved pharmaceutical performance, using a quality by design approach to support product development and optimization. The resulting formulation was characterized in terms of and in vitro release, permeation and retention studies in newborn pig skin, using Franz diffusion cells revealing the StNC have the ability to control the drug release rate and contribute to a high skin retention and/or permeation profiles. The anti-inflammatory activity accessed in vivo using the croton oil-induced ear inflammation model in mice showed that erythema and edema were attenuated in 98% following local application. These observations suggest the association of ER143 to the StNC promotes a deeper skin penetration and retention, also confirming StNC as a potential topical delivery system.
... However, UVC has difficulty penetrating the atmosphere and can reach the upper layer of the epidermis ( Figure 2). When the skin is exposed to natural sunlight or to artificially generated UVR, it is damaged by the generation of ROS, inflammatory processes, accelerated apoptosis, and the formation of DNA photo lesions [61,62] (Figure 2). In addition to free radical formation, UV directly affects DNA nucleotide base pairing [63]. ...
... A sunscreen formulation fortified with melatonin has a superior sun protection factor and the ability to counteract ROS. natural sunlight or to artificially generated UVR, it is damaged by the generation of ROS, inflammatory processes, accelerated apoptosis, and the formation of DNA photo lesions [61,62] ( Figure 2). In addition to free radical formation, UV directly affects DNA nucleotide base pairing [63]. ...
Article
Full-text available
When exposed to hostile environments such as radiation, physical injuries, chemicals, pollution, and microorganisms, the skin requires protective chemical molecules and pathways. Melatonin, a highly conserved ancient molecule, plays a crucial role in the maintenance of skin. As human skin has functional melatonin receptors and also acts as a complete system that is capable of producing and regulating melatonin synthesis, melatonin is a promising candidate for its maintenance and protection. Below, we review the studies of new metabolic pathways involved in the protective functions of melatonin in dermal cells. We also discuss the advantages of the topical use of melatonin for therapeutic purposes and skin protection. In our view, endogenous intracutaneous melatonin production, together with topically-applied exogenous melatonin and its metabolites, represent two of the most potent defense systems against external damage to the skin.
... Mel suppresses ultraviolet (UV)induced damage in human skin and human-derived cell lines (e.g., keratinocytes and fibroblasts) [38]. Mel-based emulsion for skin photoprotection has recently been developed, showing stable and effective effects [39]. Skin Mel declines with age and therefore the topical supplementation of melatonin could be an interesting anti-skin-aging strategy. ...
... Mel suppresses ultraviolet (UV)-induced damage in human skin and human-derived cell lines (e.g., keratinocytes and fibroblasts) [38]. Mel-based emulsion for skin photoprotection has recently been developed, showing stable and effective effects [39]. Skin Mel declines with age and therefore the topical supplementation of melatonin could be an interesting anti-skin-aging strategy. ...
Preprint
Full-text available
Background: Melatonin is a potent mitochondrial, cytoprotective and antioxidant molecule with potentially strong anti-aging properties. Topical melatonin has shown to improve the clinical signs of skin aging. Melatosphere™ is a new lipid-based delivery system able to improve stability and skin penetration of melatonin when used in topical formulations. No clinical studies, using objective instrumental data, are available so far regarding the positive effect of Melatosphere™ in improving wrinkles in women with mild-to-moderate skin aging. Study Aim: We evaluate, in an open prospective, evaluator-blinded trial, the effects on skin texture of 2 months treatment with a Melatosphere™ based cream. Subjects and Methods: 15 women aged >45 years with mild to moderate facial skin aging (Glogau score ≥2) participated in the trial, after their informed consent. An ANTERA 3D computer-assisted skin analysis evaluation for the assessment of coarse and fine wrinkles of the periorbital area and melanin content was performed at baseline and after two months of treatment. An evaluator-blinded Investigator Global assessment of skin elastosis, roughness, level of dyscromia, skin dryness and presence of actinic damage was also performed at the same time points using a 4-grade score from 0 (no sign) to 3 (severe sign). Results: At baseline the mean (SD) IGA score was 8.2(1.0). After 2 months the IGA score significantly decrease to 4.2(1.4) (49% reduction) (P=0.0007). ANTERA 3D evaluations showed a significant reduction in skin coarse and fine wrinkles volume in the target area of -31% and -18%, respectively. Melanin content was reduced significantly by -17%. Conclusion: Topical melatonin carried in Melatosphere improves in the short-term signs of skin aging evaluated clinically and by ANTERA 3D device in women with mild to moderate skin aging.
... The importance of coffee oil is attributed to several of its characteristics, such as its strong flavour, and its antioxidant and nutraceutical properties, which make it suitable for the food a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 and bakery industries [6][7][8][9][10][11][12][13][14][15], and for cosmetic formulation and pharmaceutical preparations [16][17][18][19][20][21][22][23][24][25]. Also, previous studies reported that the oil extracted from spent coffee grounds represents a valuable renewable source for bio-hydrotreated fuel production [26]. ...
... The RCO is a brown liquid characterized by an intense and pleasant aroma. The color of the oil is mainly due to the presence of Maillard reaction products that are obtained during the seed roasting process [23]. ...
Article
Full-text available
The aim of the present study was to establish the influence of high-temperature heating on the composition and thermal behavior of coffee oils obtained from Arabica green and roasted coffee beans, respectively. Morphological studies performed using scanning electron microscopy revealed the oil bodies uniformly distributed within the cells in both types of coffee beans analyzed. The obtained oils have a fatty acid composition rich in linoleic acid, palmitic acid, oleic acid, stearic acid, arachidic acid and linolenic acid. The total content of saturated fatty acids of investigated oils was 49.38 and 46.55%, the others being unsaturated fatty acids. The thermal behavior and thermo-oxidative stability of coffee oils extracted from green coffee beans and roasted coffee beans, the coffee oil high-temperature heated up to 200 °C, were investigated using simultaneous thermal analysis TG/DTG/DTA, in an oxidizing atmosphere. The data obtained for the analyzed samples depend mainly on the nature and compositions of fatty acids, and to a lesser extent on the roasting process of the coffee beans and the high-temperature heating process of the extracted oil. The chromatographic and TG/DTG/DTA data suggest that Arabica coffee oil has great potential for use in technological processes which require high-temperature heating (e.g. food industry or pastries).
... Amylopectin is the branched form presenting chains of α[14] linked glucose monomers arranged in a highly branched structure with α[16] branching links (Marto et al., 2017). Starch is generally a non-polluting renewable source for sustainable supply of cheaper pharmaceutical products (Santander-Ortega et al., 2010, Marto et al., 2015, Marto et al., 2016a, Marto et al., 2016c. It is produced by many plants, being the second most abundant biomass material in nature and thus an important industrial material, rated among the top ten pharmaceutical ingredients (Ochubiojo and Rodrigues, 2012). ...
... It is produced by many plants, being the second most abundant biomass material in nature and thus an important industrial material, rated among the top ten pharmaceutical ingredients (Ochubiojo and Rodrigues, 2012). Consequently, starch has been extensively used in various pharmaceutical applications such as: co-polymer, excipient for tableting, drug carrier in tissue engineering scaffolds, binder for coatings, solubility and sensorial enhancer, a stabilizer A c c e p t e d M a n u s c r i p t and a drug delivery system (Marto et al., 2015, Marto et al., 2016a, Marto et al., 2018. ...
Article
Pharmaceutical research has been focused on developing improved delivery systems while exploring new ways of using approved excipients. The present work investigated the potential of starch nanocapsules (StNC) as a topical delivery platform for hydrophilic antimicrobial drugs using minocycline hydrochloride (MH) as a model drug. Thus, a quality by design approach was used to assess the role of different factors that affect the main pharmaceutical properties of StNC prepared using an emulsification–solvent evaporation method. Full characterization was performed in terms of particle size, encapsulation efficiency, morphology and physical stability at 5 ± 3°C. Results show the surfactant and lipid contents play a major role in StNC particle size distribution. The MH loading only promoted minor changes upon StNC properties. Formulations were stable without variations on physicochemical properties. All tested formulations presented a zeta potential of +33.6±6.7 mV, indicating a good physical stability and evidencing that StNC are suitable nanocarriers for topical use.
... The intracellular production of reactive oxygen species (ROS) within HaCaT cell line of SCG extracts was assessed with a fluorimetric technique previously published. 22 Samples (at concentrations of 1 and 0.1 mg/mL) or ascorbic acid (1 mg/mL) were tested with hydrogen peroxide solution (500 μM) used for induction of ROS in cells. ...
... The cytotoxicity was evaluated using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) reduction as end point of the cell viability for 24 h of exposition according the previously published work. 22 Statistical Analysis. The GraphPad PRISM 5 software was used to perform the ANOVA analysis and Tukey−Kramer posthoc multiple comparison test. ...
Article
The aim of this study was to valorize spent coffee grounds (SCG) into bioactive extracts for improving skin health. These extracts were obtained by subcritical water extraction (SWE) at 100 bar and temperatures up to 220 ºC, in a semi-continuous mode. They were analyzed for phenolic acids, carbohydrates, antioxidant activity (AA) measured by the DPPH assay, ROS scavenging activity in keratinocyte cells, and elastase and tyrosinase inhibitory activity. SCG extracts collected up to 140 ºC had higher phenolic acids content (19.9 mg GA/gdry SCG), higher AA (EC50 of 20.6 g mL-1), and lower carbohydrate content (38 mg sugars/gdry SCG) than the fraction collected from 140 to 220 ºC (5.7 mg GA/gdry SCG, EC50 of 132.2 g mL-1, and 286 mg sugars/gdry SCG). The extracts were proven to have anti-aging and skin lightening effects by inhibiting elastase (99% and 97.9%) and tyrosinase (78.6% and 92.1%) activity. The extracts were incorporated in shear thinning and acidic hydrogels for topical application. Release (70%) and permeation studies (65.3 13.1g/cm2) as well as cytotoxicity assays were performed to evaluate the release and permeation of bioactive compounds and the safety of hydrogels.
... The cell viability was assessed with the MTT assay, which is based on the reduction of the dye MTT to formazan by cellular dehydrogenases [22]. Briefly, HaCaT subconfluent cells grown in 24-well plates were treated with several concentrations of extract (0.1 to 2 mg/mL) or of the hydrogel formulation (1 to 5 mg/mL). ...
... The effect of different concentrations of sample on the reactive oxygen species (ROS) production, induced by 500 µM hydrogen peroxide or by UVB radiation, in HaCaT cells, was evaluated by a fluorimetric method with the probe 2 ,7-dichlorodihydrofluorescein diacetate (H2-DCFDA), as described previously [22]. ...
Article
Full-text available
Fragaria vesca L. (F. vesca), popularly known as wild strawberry, is a plant from the Rosaceae family, found in temperate and subtropical areas of the northern hemisphere. F. vesca leaves have been shown to have antiseptic, emollient, and dermatological protection properties, due to the presence of bioactive compounds, such as flavonoids, phenolic acids, ellagitannins, and proanthocyanidins. In this study, a F. vesca extract was obtained by an optimized extraction process, and was characterized by HPLC, ROS scavenging activity, cytotoxicity assays in HaCaT cells, and tyrosinase inhibitory activity determination. The most active extract was then incorporated in a hydrogel with hydroxyethylcellulose at 2% (w/w), which was characterized at the physicochemical, stability, cytotoxicity, and ROS scavenging activity levels to evaluate its quality, safety, and efficacy. In vivo studies, human repeat insult patch testing, and an assay to determine their antioxidant efficacy, were also performed. The results showed that the Fragaria vesca extracts had antioxidant activity and that the F. vesca extract-based hydrogel exhibited cutaneous compatibility, acceptability and antioxidant efficacy, being stable, and suitable for topical application.
... 9 In recent years, scientists have focused on the antioxidant ability of MLT. 10 Since MLT has a high antioxidant value and can be used as a skincare product to remove free radicals in the body, researchers have mixed MLT with Pickering cream to improve the stability of MLT and used it to protect the skin from the sun. 11 On the other hand, there are more and more reports on the modification of natural MLT by chemical methods. Through the substitution modification of the MLT acetamide moiety, the molecule Neu-p11 ( Figure S1) can be used to repair memory damage and is expected to be a potential drug for the treatment of Alzheimer's disease. ...
Article
A new melatonin sulfonate derivative sodium 4-(3-(2-acetamidoethyl)-5-methoxy-1H-indol-1-yl) butane-1-sulfonate (MLTBS) with higher water solubility (695 times) and lower cytotoxicity than natural melatonin (MLT) was synthesized, yet with the same sleep aid function. The poor solubility of MLT in water has been improved with a simple chemical reaction, which solves the poor solubility of melatonin in water, overcoming the safety problem caused by adding organic reagents such as dimethyl sulfoxide (DMSO) and ethanol to increase the solubility. Moreover, the modified MLT still has the same sleep aid effect as the natural MLT and higher biological safety. As a novel potential drug for sleep aid, the new MLT derivative could also flourish the application and research of this molecule in medicine and biology.
... polystyrene [45] and polystyrene-silica-based coreshell nanocomposite particles [46]. Pickering emulsions are also used for encapsulation of drugs [47], food hydrocolloid industry [48] and for preparation of hollow microspheres [49]. ...
Article
Full-text available
The production of composite electrospun matrices of poly(ε-caprolactone) (PCL) using an emulsifier-free emulsion, made with minimal organic solvent, as precursor is reported. Pickering emulsions of PCL were prepared using modified montmorillonite (MMT) clay as the stabilizer. Hydrophobic tallow group of the modified MMT clay resulted in analogous interaction of clay with oil and aqueous phase and its adsorption at the interface to provide stability to the resultant emulsion. Composite fibrous matrices of PCL and MMT were produced using electrospinning under controlled conditions. The fiber fineness was found to alter with PCL concentration and volume fraction of the aqueous and oil phases. A higher tensile strength and modulus was obtained with inclusion of MMT in PCL electrospun matrix in comparison to a matrix made using neat PCL. The presence of clay in the fibrous matrix did not change the cell proliferation efficiency in comparison to neat PCL matrix. Composite fibrous matrices of PCL/MMT bearing enhanced tensile properties may find applications in areas other than tissue engineering for example food packaging and filtration.
... Therefore, the authors suggested that this type of vehicle would be advantageous to use in the topical formulations especially for the delivery of sunscreen agents[64]. A research group investigated a melatonin-based Pickering emulsion that showed a significantly high amount of melatonin extract in the SC as compared to epidermis and dermis, suggesting it as a promising carrier for sunscreen and moisturizing formulations[65]. On the other hand, it was reported that a starch-based oil-in-water Pickering emulsion containing humectants and oils showed excellent occlusive effect and enhanced skin hydration after topical application without any dermal irritation[66]. ...
Article
Introduction: An adequate hydration level is essential to maintain epidermal barrier functions and normal physiological activities of skin tissues. Diverse moisturizing agents and pharmaceutical formulations for dermal deliveries have thus extensively been investigated. This review comprehensively discusses scientific outcomes of moisturizing agents and pharmaceutical vehicles for skin moisturization, thereby providing insight into designing innovative pharmaceutical formulations for effective skin moisturization. Areas covered: We discussed the functions of various moisturizing agents ranging from conventional creams to novel moisturizers which has recently been explored. In addition, novel pharmaceutical formulations for efficient dermal delivery of the moisturizers, in particular, nanocarriers, were discussed along with their uses in commercial products. Expert opinion: Although various moisturizing agents have demonstrated their promising effects, exploitation of pharmaceutical formulations for their dermal delivery have been limited to few commonly used moisturizing agents. Thus, combinatorial investigation of novel moisturizers and pharmaceutical vehicles should be further conducted. As a new concept for improving skin moisturization, skin regeneration technologies using therapeutic cells have recently shown great promise for skin moisturization, but major challenges remain, such as efficient delivery and prolonged survival of such cells. Thus, novel approaches for improving skin moisturization require continuous efforts of pharmaceutical scientists to address the remaining problems.
... Doseresponse investigations revealed that 0.5% MEL was the most potent suppressive concentration against UV erythema (20). Various delivery systems have been employed for the formulation of melatonin (21)(22)(23)(24). ...
Article
Incorporation of antioxidants into sunscreens is a logical approach, yet co-delivery of them with UV filters is a challenge. Here, we purposed a combination therapy, in which the chemical UV filter, octyl methoxycinnamate, was accumulated on upper skin while the antioxidant, melatonin, can penetrate deeper layers to show its effects. Melatonin-loaded elastic niosomes and octyl methoxycinnamate Pickering emulsion were prepared separately. Lyophilized elastic niosomes were dispersed into the Pickering emulsion to prepare the proposed combination formulation. The characterization studies of the formulations revealed that elastic niosomes can be prepared with tunable nanometer sizes, whereas Pickering emulsions can encapsulate the UV filter in micrometer-sized droplets. Melatonin-loaded elastic niosomes prepared with Tween80/Span80 mixture were 146 nm with a PI of 0.438, and 58.42% entrapment efficiency was achieved. The mean diameter size of the combination formulation was 27.8 μm. Ex vivo permeation studies revealed that 7.40% of octyl methoxycinnamate and 58% of melatonin were permeated through the rat skin while 27.6% octyl methoxycinnamate and 37% of melatonin accumulated in the skin after 24 h. Cell culture studies with real-time cell analyzer showed that the proposed formulation consist of melatonin-loaded elastic niosomes and octyl methoxycinnamate Pickering emulsion had no negative effect on the cell proliferation and viability. According to α,α-diphenyl-β-picrylhydrazyl free radical scavenging method, the proposed formulation showed as high antioxidant activity as melatonin itself. It is concluded that the proposed formulation would be a promising dual therapy for UV-induced skin damage with co-delivery strategy.
... Beside those, melatonin is also synthesized in skin activated by a local melatoninergic system in protection against ultraviolet radiation (UVR) induced damages. Therefore, combination of endogenous and topically applied exogenous melatonin makes this molecule attractive as a potent antioxidant for sunscreen formulations [2][3][4]. ...
Article
A simple, fast and precise reverse phase high performance liquid chromatographic method has been developed for the simultaneous determination of Melatonin and Octyl Methoxycinnamate. Melatonin has become an attractive substrate in sunscreen formulations because of its high antioxidant and photo-protection properties. Octyl methoxycinnamate is one of the chemical UV filter that can be found most of the sunscreen formulations up to 7.5 % according Food and Drug Administration. The aim of the present study was to develop and validate a High-Performance Liquid Chromatography method for the determination of Melatonin and Octyl Methoxycinnamate in combined pharmaceutical or cosmetic applications. As a model of combined pharmaceutical applications, a microemulsion consisting of Melatonin and Octyl Methoxycinnamate was also prepared and characterized in terms of droplet size, pH and viscosity. The separation was performed with a Waters XTerra RP C18 (5 μm, 4.6 x 150 mm). All HPLC assays were performed with 10 μl injection volume, mobile phase consisting of acetonitrile and water, using gradient elution starting at 20% and ending at 90% of acetonitrile with a flow rate of 1.5 ml min-1.The eluent was monitored with UV detection at 222 nm for Melatonin and 306 nm for Octyl Methoxycinnamate. The method was validated according to ICH guidelines. Validation parameters were specificity, accuracy, precision (repeatability and reproducibility), linearity, limit of detection (LOD) and limit of quantification (LOQ). Analytical method development results indicated that the LOD values were 0.132 and 0.049 μg/ml; LOQ values were 0.4 and 0.15 μg/ml and assay exhibited a linear range of 0.5- 60 μg/ml for Melatonin and Octyl Methoxycinnamate, respectively.
... The intracellular reactive oxygen species (ROS) production was determined using the 2 ,7dichlorodihydrofluorescein diacetate (H2DCFDA) dye. H2DCFDA is a stable non-fluorescent molecule that is hydrolyzed by intracellular esterases to non-fluorescent 2 ,7 -dichlorofluorescein (DCF) which is rapidly oxidized in the presence of oxygen radicals to a highly fluorescent compound (DCF) [36,37]. Cultures at the same cell density for cell viability assay of ARPE-19 and HEK 293T cells grown in 96-well plates were incubated, after exposed for 24 h at different samples 30 min with 20 µM of H2DCFDA (ThermoFisher Scientific, Paisley, UK) in the dark at 37 • C. The medium was then removed and fresh medium was added. ...
Article
Full-text available
Pharmaceutical approaches based on nanotechnologies and the development of eye drops composed of the mucoadhesive polymers chitosan and hyaluronic acid are emerging strategies for the efficient treatment of ocular diseases. These innovative nanoparticulate systems aim to increase drugs' bioavailability at the ocular surface. For the successful development of these systems, the evaluation of mucoahesiveness (the interaction between the ocular delivery system and mucins present on the eye) is of utmost importance. In this context, the aim of the present work was to investigate the mucoadhesivity of a novel nanoparticle eye drop formulation containing an antibiotic (ceftazidime) intended to treat eye infections. Eye drop formulations comprised a polymer (hydroxypropyl) methyl cellulose (HPMC) 0.75% (w/v) in an isotonic solution incorporating chitosan/sodium tripolyphosphate (TPP)-hyaluronic acid-based nanoparticles containing ceftazidime. The viscosity of the nanoparticles, and the gels incorporating the nanoparticles were characterized in contact with mucin at different mass ratios, allowing the calculation of the rheological synergism parameter (∆η). Results showed that at different nanoparticle eye formulation:mucin weight ratios, a minimum in viscosity occurred which resulted in a negative rheological synergism. Additionally, the results highlighted the mucoadhesivity of the novel ocular formulation and its ability to interact with the ocular surface, thus increasing the drug residence time in the eye. Moreover, the in vitro release and permeation studies showed a prolonged drug release profile from the chitosan/TPP-hyaluronic acid nanoparticles gel formulation. Furthermore, the gel formulations were not cytotoxic on ARPE-19 and HEK293T cell lines, evaluated by the metabolic and membrane integrity tests. The formulation was stable and the drug active, as shown by microbiological studies. In conclusion, chitosan/TPP-hyaluronic acid nanoparticle eye drop formulations are a promising platform for ocular drug delivery with enhanced mucoadhesive properties.
... The intracellular ROS production can be evaluated through a fluorimeter technique that uses 2,7′ dichlorodihydrofluorescein diacetate (H2-DCFDA, Life Technologies, UK) and HaCaT sub-confluent cells (Marto et al., 2016a). Ascorbic acid was used as a negative control and the medium subjected to the oxidative stress inducer (H 2 O 2 or UVB radiation) as positive control. ...
Article
Full-text available
Cynara scolymus L. (CS), usually known as globe artichoke, is a Mediterranean plant with antioxidant properties due to its content of polyphenols, including caffeoylquinic and dicaffeoylquinic acids. The use of bioactive ingredients or phytochemicals extracted from plant tissues in cosmetics is increasing, thus artichoke extract due to its promising constituents can be incorporated in topical formulations. The aim of this study was the chemical characterization of different CS extracts in order to investigate the antioxidant and the sun protection potential in topical formulations. Aqueous extracts were analyzed by HPLC to quantify target compounds, such as cynarin, chlorogenic acid and cynaroside. Antioxidant activity by DPPH assay and ROS scavenging activity in HaCaT cells, as well as cytotoxicity assays and sun protection factor were assessed. The results showed that CS extract and CSC fraction, one of the purified fractions, were rich in polyphenols and presented antioxidant and pho-toprotective activity. Then, both fractions were incorporated in two topical formulations: O/W emulsion and hydrogel. Physicochemical characterization, microbiological control, cytotoxicity assays and ROS scavenging activity in HaCaT cells were performed to ensure the quality, safety and efficacy of the products developed. In vivo studies, Human Repeat Insult Patch Testing and an assay to determine their antioxidant capacity, were also performed. Besides the excellent antioxidant and photoprotective activity, the final formulations proved to be also suitable and safe for topical use.
... Human repeat insult patch test (HRIPT). The safety evaluation was performed according to the Marzulli and Maibach (1976) HRIPT protocol, as previously described (Marzulli and Maibach, 1976;Marto et al., 2016a). For this study 52 healthy volunteers were selected and duly informed about the procedure, having signed the informed written consent. ...
Article
Full-text available
The safety profile of the ingredients used in topical dosage forms and its evaluation is an issue of utmost importance. A suitable equilibrium between safety and efficacy is crucial before promoting a dermatological product. The aim of this work was to assess the safety and biological effects of starch-based vehicles (St-BV) used in such products. The hazard, exposure and dose-response assessment were used to characterize the risk of each ingredient. The EpiSkin™ assay and human repeat insult patch tests were performed to compare the theoretical safety assessment to in vitro and in vivo data. The efficacy of the St-BV was studied using biophysical measurements in human volunteers during 28 days, showing that all ingredients and their combinations were safe for the consumer. Tissue viability determined using the EpiSkin™ testing reached values between 84.0 ± 5.0% and 98.0 ± 8.6% after application of St-BV, which were considered as non-irritant to the skin. These observations were confirmed by the in vivo studies where the St-BV did not induce any sensitization on the volunteers, being safe for human use. Moreover, St-BV increased skin hydration and microcirculation, emerging as an attractive alternative to chemical raw materials.
... Mel suppresses ultraviolet (UV)induced damage in human skin and human-derived cell lines (e.g., keratinocytes and fibroblasts) [38]. Mel-based emulsion for skin photoprotection has recently been developed, showing stable and effective effects [39]. Skin Mel declines with age and therefore the topical supplementation of melatonin could be an interesting anti-skin-aging strategy. ...
Article
Full-text available
Melatonin is a potent mitochondrial, cytoprotective and antioxidant molecule with potentially strong anti-aging properties. Topical melatonin has been shown to improve the clinical signs of skin aging. Melatosphere™ is a new lipid-based delivery system able to improve stability and skin penetration of melatonin when used in topical formulations. No clinical studies, using objective instrumental data, are available so far regarding the positive effect of Melatosphere™ in improving wrinkles in women with mild to moderate skin aging. In an open prospective, evaluator-blinded trial, we evaluate the effects on skin texture of two months of treatment with a Melatosphere™-based cream. Fifteen women aged >45 years with mild to moderate facial skin aging (Glogau score 2–4) participated in the trial, after providing their informed consent. An ANTERA 3D computer-assisted skin analysis evaluation for the assessment of coarse and fine wrinkles of the periorbital area and melanin content was performed at baseline and after two months of treatment. An evaluator-blinded Investigator Global Assessment (IGA) of skin elastosis, roughness, level of dyschromia, skin dryness and the presence of actinic damage was also performed at the same time points using a four-grade score from 0 (no sign) to 3 (severe sign). At baseline, the mean (SD) IGA score was 8.2 (1.0). After two months, the IGA score significantly decreased to 4.2 (1.4) (49% reduction) (p = 0.0007). ANTERA 3D evaluations showed a significant reduction in the coarse and fine wrinkle volume in the target area of −31% and −18%, respectively. Melanin content was reduced significantly by −17%. Topical melatonin carried in Melatosphere™ improves, in the short term, signs of skin aging evaluated clinically and using the ANTERA 3D device in women with mild to moderate skin aging.
... Regarding highly lipophilic molecules, Pickering emulsions promote high accumulation in the SC. The practical utility of such behaviour is either preventing skin penetration of molecules that should be retained at the skin surface, e.g., sunscreens and topical antibiotics, or using the SC as a reservoir for slow release of the drug to the deeper skin layers [35,36]. Therefore, regarding a pharmaceutical application, w/o Pickering emulsions are particularly indicated for sustained and targeted drug release to the viable epidermis, forming a drug reservoir in the deeper layers of SC. ...
Article
Full-text available
The present study investigated a new approach to treat superficial skin infections by topical application of minocycline hydrochloride (MH) formulated in a novel starch-based Pickering emulsion (ASt-emulsions). The emulsions were fully characterized in terms of efficacy, as well as in vitro release and permeation studies. The emulsions provided a prolonged MH release, always above its minimum inhibitory concentration against Staphylococcus aureus, although the drug did not permeate through the entire skin layer. The in vitro antibacterial activity of MHASt-emulsions against S. aureus was confirmed and their therapeutic efficacy was assessed using an in vitro skin-adapted agar diffusion test. In vivo antibacterial activity, evaluated using the tape-stripping infection model in mice, showed the topical administration of MH was effective against superficial infections caused by S. aureus. This study supports the potential of ASt-emulsions as promising platforms for topical antibiotic delivery, contributing to a new perspective on the treatment of superficial bacterial infections.
... HaCaT sub-confluent cells grown in 96 well plates were incubated for 30 min with 20 µM of H2-DCFDA in the dark, at 37 • C and the procedure was performed according a previous published work [23]. Data from 12 replicates was reported as relative fluorescence units (RFU) percentage and expressed as a mean fluorescence ratio (fluorescence of exposed cells/fluorescence of unexposed control from the same experiment). ...
Article
Full-text available
Quercus Suber Bark from Quercus suber L. is a natural, renewable and biodegradable biomaterial with multifunctional proprieties. In this study, we used it as solid particles to stabilize a Pickering emulsion. The main goal was to produce an optimized topical formulation using biocompatible organic particles as stabilizers of the emulsion instead of the common surfactants, whilst benefiting from Quercus suber L. proprieties. In this work, a Quality by Design (QbD) approach was successfully applied to the production of this emulsion. A screening design was conducted, identifying the critical variables of the formula and process, affecting the critical quality attributes of the emulsion (droplet size distribution). The optimization of the production was made through the establishment of the design space. The stability was also investigated during 30 days, demonstrating that Quercus Suber Bark-stabilized emulsions are stable since the droplet size distribution lowers. In vitro studies were performed to assess antioxidant and antiaging efficacy, which revealed that the formulation had indeed antioxidant proprieties. A physicochemical characterization demonstrated that the formulation presents a shear-thinning fluid, ideal for topical administration. The in vivo compatibility study confirmed that the final formulation is not skin irritant, being safe for human use. A sensorial analysis was also performed, using a simple sensory questionnaire, revealing very positive results. Thus, the use of Quercus Suber Bark particles as a multifunctional solid ingredient contributed to achieve a stable, effective and innovative Pickering emulsion with a meaningful synergistic protection against oxidative stress.
Article
Studies of particle-stabilized biphasic structures have greatly expanded the possibilities of multiphasic systems by pro-ducing liquid composites with unique morphologies and properties. The solvent transfer-induced phase separation (STRIPS) method was previously introduced to prepare bicontinuous interfacially jammed emulsion gels (bijels), a unique class of particle-stabilized biphasic structures. Although STRIPS enables continuous processing, the requirement of an external aqueous phase may limit its application. In this work, a new method to produce a variety of three-dimensional multiphasic structures including bijels via vapor-induced phase separation (VIPS) is demonstrated. VIPS en-ables the fabrication of films and coatings by spreading or spraying a particle-laden suspension onto a surface without the need of an outer aqueous phase. Intriguingly, a regime in which secondary nucleation of structures occurs within phase separated domains is identified, leading to hierarchically bicontinuous biphasic structures. The dimensions of phase separated domains can be controlled by the rate of co-solvent removal. Moreover, a different path to bicontinu-ous morphology is identified which does not occur via spinodal decomposition, but rather relies on the formation of per-colating structures of partially coalesced particle-covered droplets. The VIPS process provides a scalable path to pro-duce bicontinuous biphasic composites with hierarchical structures for advanced coatings and membranes applications.
Article
Sonication is one of the most commonly used methods to synthesize Pickering emulsions. Yet, the process of emulsion sonication is rarely characterized in detail and acoustic conditions are largely determined by experimenter's personal experience. In this study, the role of sonication in the formation of Pickering emulsions from amphiphilic gold nanoparticles was investigated using a new sample environment combining ultrasound delivery with ultra-small-angle X-ray scattering (USAXS) measurements. The detection of acoustic cavitation and the simultaneous analysis of structural data via USAXS demonstrated direct correlation between Pickering emulsion formation and cavitation events. There was no evidence of spontaneous adsorption of particles onto the oil-water interface without ultrasound, which suggests the presence of a stabilizing force. Acoustically detected cavitation events could originate in the bulk solvent and/or inside the emulsion droplets. These events helped overcome energy barriers to induce particle adsorption.
Article
Full-text available
Functionalized matrices have been sought for their application in sensors, filtration, energy storage, catalysis and tissue engineering. We report formation of an inorganic-organic composite matrix based on poly(ε-caprolactone) (PCL) functionalized with hydrophobically modified silica (m-silica) fabricated with reduced organic solvent usage. The matrix was obtained via electrospinning of a water-in-oil emulsion of PCL that was stabilized by judicious choice of m-silica as a Pickering agent resulting into an emulsifier free matrix. Inclusion of m-silica in PCL matrix resulted in enhancing tensile properties and cell proliferation efficiency. The electrospun composite matrix was free from any emulsifier or template polymer thus any abrupt loss in mechanical properties was prevented when the matrix was subjected to aqueous conditions. The inorganic-organic biodegradable composite matrices thus produced using an emulsifier free emulsion find applications in tissue engineering and may further be evaluated for other areas including selective sorption and separation.
Article
As the personal care industry evolves, formulators are seeking innovative solutions for their formulations' needs, and for ingredients that can offer multiple functions within formulations. Considering that essential oils (EOs) may present a wide spectrum of biological activities, the composition, antimicrobial and antioxidant activity of Portuguese Thymbra capitata, Thymus caespititius and Myrtus communis EOs were assessed in order to evaluate them as preservatives and antioxidants in topical emulsions. The in vivo safety application of some emulsions was also tested. T. capitata EO was mainly constituted by carvacrol (73%), whereas α-terpineol (27%), p-cymene (14%) and carvacrol (10%) dominated Th. caespititius EO, and 1,8-cineole (37%) was dominant in M. communis EO. The minimum inhibitory concentration of T. capitata, Th. caespititius and M. communis EOs was 0.4 μg/mL against C. albicans and ranged between 0.4 and 30.7 μg/mL against A. brasiliensis. Gram-positive bacteria were more susceptible to each EO than Gram-negative bacteria. T. capitata EO showed significantly higher antioxidant activity than Th. caespititius and M. communis EOs. EOs incorporated in emulsions showed preservative activity against all microorganisms tested and T. capitata EO emulsions showed powerful reactive oxygen species (ROS) scavenging effects. A safety evaluation study was performed with 0.10% and 0.01% T. capitata EO emulsions according to the Human Repeat Insult Patch Test (HRIPT). All emulsions were considered safe for topical application. T. capitata, Th. caespititius and M. communis significantly improved the microbiological quality of the prepared emulsions and may constitute a powerful alternative to the current preservatives and antioxidants for use in topical formulations.
Article
Onychomycosis is a fungal nail infection. The development of new topical antifungal agents for the treatment of onychomycosis has focused on formulation enhancements that optimize the pharmacological characteristics required for its effective treatment. Polyurethanes (PUs) have never been used in therapeutic nail lacquers. The aim of this work has been the development of new PU based nail lacquers with antifungal activity containing 1.0% (w/w) of terbinafine hydrochloride. The biocompatibility, wettability and the prediction of the free volume in the polymeric matrix were assessed using a human keratinocytes cell line, contact angle and Positron Annihilation Lifetime Spectroscopy (PALS) determinations, respectively. The morphology of the films obtained was confirmed by Scanning Electron Microscopy (SEM), while the nail lacquers' bioadhesion to nails was determined by mechanical tests. Viscosity, in vitro release profiles and antifungal activity were also assessed. This study demonstrated that PU-terbinafine based nail lacquers have good keratinocyte compatibility, good wettability properties and adequate free volume. They formed a homogenous film after application, with suitable adhesion to the nail plate. Furthermore, the antifungal test results demonstrated that the terbinafine released from the nail lacquer Formulation A PU 19 showed activity against dermatophytes namely, Tricophyton rubrum.
Article
Background: Melatonin is emerging as a promising therapeutic agent, mainly due to its role as antioxidant. Substantial evidences show that melatonin is potentially effective in a variety of diseases as cancer, inflammation and neurodegenerative diseases. The excellent antioxidant capacity with pharmacokinetics characteristics and the emerging search for new pharmaceutical nanotechnology based systems, make it particularly attractive to elaborate nanoplatforms based on melatonin for biomedical or cosmetic dermal applications. Different nanosystems for dermal delivery have been investigated. Objective: This review focuses on nanocarrier production strategies, dermal melatonin application and delivery advances in vivo and in vitro. Equally, future perspectives of this assisted melatonin delivery have also been discussed. Method: In the current review, we have revised relevant articles of the available literature using the major scientific databases. Results: One hundred and thirteen papers were included in the review, the majority of which represent latest researches in nanosized platforms for the dermal delivery of melatonin including liposomes, ethosomes, niosomes, polymeric nanoparticles, solid lipid nanoparticles and cyclodextrins. Furthermore, relevant papers reporting in vitro and in vivo application studies of these nano-based melatonin platforms were also discussed. Conclusion: The use of nanoplatforms for the dermal melatonin delivery as antioxidant agent could improve the efficacy of conventional melatonin administration due to the preservation of the drug from premature oxidation and the enhancement of drug permeation through the skin providing greater exposure times.
Article
Objective: The increasing interest for the Pickering emulsions is based on the possibility to replace classical emulsifiers by the solid particles. This approach is extremely attractive for the cosmetic field. But, the main difficulty is to obtain stable emulsions with appreciable skin feel. However, there is no information about the texture of such systems. The aim of this study is to formulate and describe the textural properties of cosmetic Pickering emulsions compared to conventional systems. Methods: Three metal oxides were selected: titanium dioxide, zinc oxide and silicon dioxide, able to form stable and totally emulsified systems. A conventional emulsifier was used to formulate the emulsion of reference. Finally, the mixture of two emulsifying systems, combining both, surfactant and particles, was also studied. Then, a sensory panel was asked to quantify the intensities of the perception of the seven discriminating attributes. Results: Each particle brought its properties to the textural perception of the emulsion. TiO2 particles ensured the whitening effect of the emulsions, SiO2 provided the screech residue, while ZnO gave intermediate results. The conventional surfactant was perceived as glossy, greasy and more difficult to spread. The particle/surfactant mixtures gave mostly in-between results. Conclusions: The study shows that the sensory profile of Pickering emulsions is indirectly and directly governed by the particle properties used for the emulsion stabilisation: indirectly, through affecting the emulsion orientation (oil in water or water in oil), the droplet organisation and viscosity, and directly, through the particle perception on the skin surface.
Article
The skin as a neuroendocrine organ and the role of neuroendocrine signaling in the development of disorders affecting the skin and its appendages has received increasing attention in the last years. Different neuroendocrine systems have been described in the barrier organ skin, including the thyroid system, the hypothalamic‐pituitary‐adrenal axis, the opioid, the endocannabinoid, the cholinergic, the secosteroidogenic and the serotonergic systems. All of these systems have been implicated in the development of skin diseases, which often have an inflammatory origin. These discoveries have led to an increase in the development of new drugs targeting components of neuroendocrine signaling pathways. Additionally, attempts have been made to repurpose already approved drugs targeting neuroendocrine signaling pathways in other organs for the treatment of skin diseases. Recently published results from preclinical and clinical studies look promising and may offer improved therapies to patients suffering from skin diseases in the near future. In this review, from a pharmaceutical point of view, we focus on recent progress in synthetic drug development of compounds targeting neuroendocrine signaling in the skin and its appendages to treat skin diseases such as atopic dermatitis, psoriasis, acne, alopecia areata and hyperhidrosis.
Article
Full-text available
Pickering emulsions differ from classical emulsions, because the first are stabilized by solid particles instead of surfactants. This type of emulsions has been widely investigated in pharmaceutical and cosmetic fields since they present less adverse effects than the classical emulsions that are stabilized by surfactants. The present study was conducted in order to characterize physically and chemically a preservative free and surfactant-free w/o emulsion for topical application and to evaluate its safety profile. Oscillatory and steady state shear measurements were performed for angular frequencies (ω) between 1 and 100 rad s-1 and shear rates ( ) between 1 and 1000 s-1 at 25 ºC, and the emulsions were examined by brightfield light microscopy. The antimicrobial activity was performed according to a modification of membrane filtration method described in the Ph.Eur.. In order to predict the cutaneous irritation to the emulsion the cell viability was evaluated using Df and HaCaT cell lines in a MTT assay. A HRIPT was used to study the irritancy and sensitizing potential of emulsion in 53 volunteers. Rheological measurements indicated that the system is well structured. The microstructure is related to the rheological behaviour in relation to particle size, shape and distribution. The antimicrobial study demonstrates that this particular w/o emulsions present self-preservation properties. Cytotoxicity results showed that the emulsion can be considered non-irritant. And in vivo studies confirmed that both emulsions did not induce any irritative or allergic reactions, showing that this product show very good skin compatibility. This study confirms that starch Pickering emulsions present a well structure system with a safe profile and the use of appropriate excipients allows preparing w/o emulsions with the obvious benefits of avoiding the drawbacks often associated with antimicrobial preservatives and surfactants agents.
Article
Full-text available
The human skin is not only a target for the protective actions of melatonin, but also a site of melatonin synthesis and metabolism, suggesting an important role for a local melatoninergic system in protection against ultraviolet radiation (UVR) induced damages. While melatonin exerts many effects on cell physiology and tissue homeostasis via membrane bound melatonin receptors, the strong protective effects of melatonin against the UVR-induced skin damage including DNA repair/protection seen at its high (pharmocological) concentrations indicate that these are mainly mediated through receptor-independent mechanisms or perhaps through activation of putative melatonin nuclear receptors. The destructive effects of the UVR are significantly counteracted or modulated by melatonin in the context of a complex intracutaneous melatoninergic anti-oxidative system with UVR-enhanced or UVR-independent melatonin metabolites. Therefore, endogenous intracutaneous melatonin production, together with topically-applied exogenous melatonin or metabolites would be expected to represent one of the most potent anti-oxidative defense systems against the UV-induced damage to the skin. In summary, we propose that melatonin can be exploited therapeutically as a protective agent or as a survival factor with anti-genotoxic properties or as a "guardian" of the genome and cellular integrity with clinical applications in UVR-induced pathology that includes carcinogenesis and skin aging.
Article
Full-text available
Spent coffee grounds (SCG), which are the residue obtained from the treatment of coffee with hot water or steam, can be used for industrial applications, due to the high content in lipids. The cosmetic products might be a suitable application for these types of residues because the barrier properties of the stratum corneum (SC) are largely dependent on the intactness of the lipid lamellae that surrounds the corneocytes. The purpose of this work was to assess the feasibility of using the lipid fraction of SCG extracted with supercritical carbon dioxide in the development of new cosmetic formulations with improved skin lipids (sebum) and hydration. The use of spent coffee lipid extract in cosmetic industry seems to be a suitable approach to recycle the wastes from coffee industry. Emulsion containing 10% of the lipid fraction of SCG (SpentCofOil cream) presented promising characteristics in the improvement of sebum skin levels with a good acceptance by consumers when compared to an emulsion containing 10% w/w of green coffee oil (GreenCofOil cream) and a placebo without coffee oil (NoCofOil cream). Practical applications: In this work, the authors develop and characterize a cream containing 10% of the lipid fraction of SCG extracted with supercritical carbon dioxide with improved skin lipids (sebum) and hydration.
Article
Full-text available
We investigated the protective effects of melatonin and its metabolites: 6-hydroxymelatonin (6-OHM), N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), N-acetylserotonin (NAS), and 5-methoxytryptamine (5-MT) in human keratinocytes against a range of doses (25, 50, and 75 mJ/cm(2) ) of ultraviolet B (UVB) radiation. There was significant reduction in the generation of ROS (50-60%) when UVB- exposed keratinocytes were treated with melatonin or its derivatives. Similarly melatonin and its metabolites reduced the nitrite and hydrogen peroxide levels that were induced by UVB as early as 30 min after the exposure. Moreover, melatonin and its metabolites enhanced levels of reduced glutathione in keratinocytes within 1 h after UVB exposure in comparison to control cells. Using proliferation assay, we observed a dose-dependent increase in viability of UVB- irradiated keratinocytes that were treated with melatonin or its derivatives after 48 h. Using the dot-blot technique and immunofluorescent staining we also observed that melatonin and its metabolites enhanced the DNA repair capacity of UVB-induced 6-4PP or CPD generation in human keratinocytes. Additional evidence for induction of DNA repair in cells exposed to UVB and treated with the indole compounds was shown using the Comet assay. Finally, melatonin and its metabolites further enhanced expression of p53 phosphorylated at Ser-15 but not at Ser-46 or its non- phosphorylated form. In conclusion, melatonin, its precursor NAS, and its metabolites 6-OHM, AFMK, 5-MT, which are endogenously produced in keratinocytes, protect these cells against UVB-induced oxidative stress and DNA damage. This article is protected by copyright. All rights reserved.
Article
Full-text available
Abstract Non-steroid anti-inflammatory drugs (NSAIDs), such as etofenamate, are among the most prescribed drugs used for their analgesic, anti-rheumatic, antipyretic and anti-inflammatory properties. Topical formulations have the main advantage of targeted delivery. However, drugs must overcome the skin due to its role as a physical and chemical barrier against the penetration of chemicals and microorganisms. This barrier must be altered to allow the permeation of drugs at a suitable rate to the desired site of activity. Permeation modulators can intercalate the skin outer layers causing structure disruption, opening an energetically favourable route for the drug to diffuse through. The aim of this work was the development of hydroalcoholic gels containing 5.0% (w/w) of etofenamate for topical administration with anti-inflammatory activity and enhanced drug delivery. The physical and chemical characterization, in vitro release and permeation studies and in vivo anti-inflammatory activity were assessed. The gel with 30% ethanol showed in vivo anti-inflammatory activity with suitable physical chemical and microbiologic characteristics. In vitro release and permeation studies revealed that the different amounts of ethanol used influenced the release profiles of etofenamate. Moreover, it was demonstrated that this formulation is an adequate vehicle for the etofenamate skin permeation.
Article
Full-text available
Indolic and kynuric pathways of skin melatonin metabolism were monitored by liquid chromatography mass spectrometry in human keratinocytes, melanocytes, dermal fibroblasts, and melanoma cells. Production of 6-hydroxymelatonin [6(OH)M], N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) and 5-methoxytryptamine (5-MT) was detected in a cell type-dependent fashion. The major metabolites, 6(OH)M and AFMK, were produced in all cells. Thus, in immortalized epidermal (HaCaT) keratinocytes, 6(OH)M was the major product with Vmax = 63.7 ng/10(6) cells and Km = 10.2 μM, with lower production of AFMK and 5-MT. Melanocytes, keratinocytes, and fibroblasts transformed melatonin primarily into 6(OH)M and AFMK. In melanoma cells, 6(OH)M and AFMK were produced endogenously, a process accelerated by exogenous melatonin in the case of AFMK. In addition, N-acetylserotonin was endogenously produced by normal and malignant melanocytes. Metabolites showed selective antiproliferative effects on human primary epidermal keratinocytes in vitro. In ex vivo human skin, both melatonin and AFMK-stimulated expression of involucrin and keratins-10 and keratins-14 in the epidermis, indicating their stimulatory role in building and maintaining the epidermal barrier. In summary, the metabolism of melatonin and its endogenous production is cell type-dependent and expressed in all three main cell populations of human skin. Furthermore, melatonin and its metabolite AFMK stimulate differentiation in human epidermis, indicating their key role in building the skin barrier.-Kim, T.-K., Kleszczyński, K., Janjetovic, Z., Sweatman, T., Lin, Z., Li, W., Reiter, R. J., Fischer, T. W., Slominski, A. T. Metabolism of melatonin and biological activity of intermediates of melatoninergic pathway in human skin cells.
Article
Full-text available
Melatonin is a methoxyindole synthesized within the pineal gland. The hormone is secreted during the night and appears to play multiple roles within the human organism. The hormone contributes to the regulation of biological rhythms, may induce sleep, has strong antioxidant action and appears to contribute to the protection of the organism from carcinogenesis and neurodegenerative disorders. At a therapeutic level as well as in prevention, melatonin is used for the management of sleep disorders and jet lag, for the resynchronization of circadian rhythms in situations such as blindness and shift work, for its preventive action in the development of cancer, as additive therapy in cancer and as therapy for preventing the progression of Alzheimer's disease and other neurodegenerative disorders.
Article
Full-text available
Like the whole organism, skin follows the process of aging during life-time. Additional to internal factors, several environmental factors, such as solar radiation, considerably contribute to this process. While fundamental mechanisms regarding skin aging are known, new aspects of anti-aging agents such as melatonin are introduced. Melatonin is a hormone produced in the glandula pinealis that follows a circadian light-dependent rhythm of secretion. It has been experimentally implicated in skin functions such as hair cycling and fur pigmentation, and melatonin receptors are expressed in many skin cell types including normal and malignant keratinocytes, melanocytes and fibroblasts. It possesses a wide range of endocrine properties as well as strong antioxidative activity. Regarding UV-induced solar damage, melatonin distinctly counteracts massive generation of reactive oxygen species, mitochondrial and DNA damage. Thus, there is considerable evidence for melatonin to be an effective anti-skin aging compound, and its various properties in this context are described in this review.
Article
Full-text available
UV radiation (UVR) induces serious structural and functional alterations in human skin leading to skin aging and carcinogenesis. Reactive oxygen species are key players in UVR-mediated photodamage and induce the DNA-base-oxidized, intermediate 8-hydroxy-2'-deoxyguanosine (8-OHdG). Herein, we report the protective action of melatonin against UVR-induced 8-OHdG formation and depletion of antioxidative enzymes using ex vivo human full-thickness skin exposed to UVR in a dose (0, 100, 300 mJ/cm(2) )- and time-dependent manner (0, 24, 48 hr post-UVR). Dynamics of depletion of antioxidative enzymes including catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD), or 8-OHdG formation were studied by real-time PCR and immunofluorescence/immunohistochemical staining. UVR-treated skin revealed significant and immediate (0 hr 300 mJ/cm(2) ) reduction of gene expression, and this effect intensified within 24 hr post-UVR. Simultaneous increase in 8-OHdG-positive keratinocytes occurred already after 0 hr post-UVR reaching 71% and 99% up-regulation at 100 and 300 mJ/cm(2) , respectively (P < 0.001). Preincubation with melatonin (10(-3) m) led to 32% and 29% significant reductions in 8-OHdG-positive cells and the prevention of antioxidative enzyme gene and protein suppression. Thus, melatonin was shown to play a crucial role as a potent antioxidant and DNA protectant against UVR-induced oxidative damage in human skin.
Article
Full-text available
Skin, the body's largest organ, is strategically located at the interface with the external environment where it detects, integrates, and responds to a diverse range of stressors including solar radiation. It has already been established that the skin is an important peripheral neuro-endocrine-immune organ that is tightly networked to central regulatory systems. These capabilities contribute to the maintenance of peripheral homeostasis. Specifically, epidermal and dermal cells produce and respond to classical stress neurotransmitters, neuropeptides, and hormones. Such production is stimulated by ultraviolet radiation (UVR), biological factors (infectious and noninfectious), and other physical and chemical agents. Examples of local biologically active products are cytokines, biogenic amines (catecholamines, histamine, serotonin, and N-acetyl-serotonin), melatonin, acetylocholine, neuropeptides including pituitary (proopiomelanocortin-derived ACTH, beta-endorphin or MSH peptides, thyroid-stimulating hormone) and hypothalamic (corticotropin-releasing factor and related urocortins, thyroid-releasing hormone) hormones as well as enkephalins and dynorphins, thyroid hormones, steroids (glucocorticoids, mineralocorticoids, sex hormones, 7-delta steroids), secosteroids, opioids, and endocannabinoids. The production of these molecules is hierarchical, organized along the algorithms of classical neuroendocrine axes such as hypothalamic-pituitary-adrenal axis (HPA), hypothalamic-thyroid axis (HPT), serotoninergic, melatoninergic, catecholaminergic, cholinergic, steroid/secosteroidogenic, opioid, and endocannbinoid systems. Dysregulation of these axes or of communication between them may lead to skin and/ or systemic diseases. These local neuroendocrine networks are also addressed at restricting maximally the effect of noxious environmental agents to preserve local and consequently global homeostasis. Moreover, the skin-derived factors/systems can also activate cutaneous nerve endings to alert the brain on changes in the epidermal or dermal environments, or alternatively to activate other coordinating centers by direct (spinal cord) neurotransmission without brain involvement. Furthermore, rapid and reciprocal communications between epidermal and dermal and adnexal compartments are also mediated by neurotransmission including antidromic modes of conduction. In conclusion, skin cells and skin as an organ coordinate and/or regulate not only peripheral but also global homeostasis.
Article
Full-text available
Background: Coffee oil potently raises serum cholesterol levels in humans. The diterpenes cafestol and kahweol are responsible for this elevation. Coffee oil also causes elevation of liver enzyme levels in serum. It has been suggested that cafestol is mainly responsible for the effect on serum cholesterol levels and that kahweol is mainly responsible for the effect on liver enzyme levels. The objective of this study was to investigate whether coffee oil that only contains a minute amount of kahweol indeed does not cause elevation of liver enzyme levels.
Article
Full-text available
Ethanol is widely used in all kinds of products with direct exposure to the human skin (e.g. medicinal products like hand disinfectants in occupational settings, cosmetics like hairsprays or mouthwashes, pharmaceutical preparations, and many household products). Contradictory evidence about the safety of such topical applications of the alcohol can be found in the scientific literature, yet an up-to-date risk assessment of ethanol application on the skin and inside the oral cavity is currently lacking. The first and foremost concerns of topical ethanol applications for public health are its carcinogenic effects, as there is unambiguous evidence for the carcinogenicity of ethanol orally consumed in the form of alcoholic beverages. So far there is a lack of evidence to associate topical ethanol use with an increased risk of skin cancer. Limited and conflicting epidemiological evidence is available on the link between the use of ethanol in the oral cavity in the form of mouthwashes or mouthrinses and oral cancer. Some studies pointed to an increased risk of oral cancer due to locally produced acetaldehyde, operating via a similar mechanism to that found after alcoholic beverage ingestion. In addition, topically applied ethanol acts as a skin penetration enhancer and may facilitate the transdermal absorption of xenobiotics (e.g. carcinogenic contaminants in cosmetic formulations). Ethanol use is associated with skin irritation or contact dermatitis, especially in humans with an aldehyde dehydrogenase (ALDH) deficiency. After regular application of ethanol on the skin (e.g. in the form of hand disinfectants) relatively low but measurable blood concentrations of ethanol and its metabolite acetaldehyde may occur, which are, however, below acute toxic levels. Only in children, especially through lacerated skin, can percutaneous toxicity occur. As there might be industry bias in many studies about the safety of topical ethanol applications, as well as a general lack of scientific research on the long-term effects, there is a requirement for independent studies on this topic. The research focus should be set on the chronic toxic effects of ethanol and acetaldehyde at the point of impact, with special regard to children and individuals with genetic deficiencies in ethanol metabolism.
Article
An overview of keratinocyte and melanocyte function is provided. The processes of cutaneous aging and photoaging are defined, and age-associated modulations in gene expression are described. The changes in keratinocytes and melanocytes that occur with skin aging and photoaging and the characteristics of chronologically aged vs. photoaged skin are delineated. Mutations that are found in malignant and premalignant tumours of epidermal origin are described.
Article
In the present study, we isolated the fixed oil from the dried seeds of Nigella sativa Linn. (Kalongi) by petroleum ether (40-60°C) using a Soxhlet apparatus, as described by AOAC (1990). Efforts were made to formulate sunscreen cream using extracted Nigella sativa L. seed fixed oil. Evaluation of same was done for sunscreen activity by using in vitro SPF method using optometrics LLC, SPF-290S instrument. The protection factor is calculated over the wavelength range from 290 - 400nm as per US-FDA standards. SPF of formulation was found 1.05 with ultra boot star rating 2 which approaches toward sunscreen activity.
Article
Previously, we demonstrated that skin cells metabolize melatonin to 6-hydroxymelatonin, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) and 5-methoxytryptamine. In this study, we determined that N(1)-acetyl-5-methoxykynuramine (AMK) is endogenously produced in the human epidermis from melatonin through the kynuric pathway. The epidermal content of AMK (average from 13 subjects) is 0.99 ± 0.21 ng/mg protein, being significantly higher in African Americans (1.50 ± 0.36 ng/mg protein) than in Caucasians (0.56 ± 0.09 ng/mg protein). It is especially high in young African Americans. The levels do not differ significantly between males and females. In vitro testing using HaCaT keratinocytes has shown that exogenously added melatonin is metabolized to AMK in a dose dependent manner with a Vmax = 388 pg/million cells and Km = 185 μM. AMK production is higher in melanized than in amelanotic melanoma cells. Testing of DNA incorporation shows that AMK has anti-proliferative effects in HaCaT and SKMEL-188 cells (non-pigmented and pigmented). AMK also inhibits growth of normal melanocytes but has no significant effect on melanogenesis or cell morphology. These findings indicate that anti-proliferative effects of AMK are not related to melanin pigmentation. In summary, we show for the first time that AMK is produced endogenously in the human epidermis, that its production is affected by melanin skin pigmentation, and that AMK exhibits anti-proliferative effects in cultured keratinocytes and melanoma cells.
Both genetic (intrinsic) and environmental (extrinsic) factors contribute to the phenotypic changes in cutaneous aging. However, only recently have the underlying molecular mechanisms involved in these changes been elucidated. DNA damage to both genomic and mitochondria) DNA and subsequent DNA repair contribute greatly to age-associated skin changes and carcinogenesis. Better understanding of these intricate, interwoven mechanisms involved in DNA damage and repair might help to develop new strategies in preventing and treating changes of intrinsic skin aging and photoaging, improving skin appearance and reducing the risk of skin cancer.
Article
The copper sequestering ability of melatonin and its metabolites cyclic 3-hydroxymelatonin (3OHM), N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), and N1-acetyl-5-methoxykynuramine (AMK) was investigated within the frame of the Density Functional Theory. It was demonstrated that these compounds are able of chelating copper ions, yielding stable complexes. The most likely chelation sites were identified. Two different mechanisms were modeled, the direct-chelation mechanism (DCM) and the coupled-deprotonation-chelation mechanism (CDCM). It is proposed that, under physiological conditions, CDCM would be the main chelation route for Cu(II). It was found that melatonin and its metabolites fully inhibited the oxidative stress induced by Cu(II)-ascorbate mixtures, via Cu(II) chelation. In the same way melatonin, AFMK, and 3OHM also prevented the first step of the Haber-Weiss reaction, consequently turning off the •OH production via the Fenton reaction. Therefore, it is proposed that, in addition to the previously reported free radical scavenging cascade, melatonin is also involved in a concurrent “chelating cascade” thereby contributing to a reduction in oxidative stress. 3OHM was identified as the most efficient of the studied compounds for that purpose, supporting the important role of this metabolite in the beneficial effects of melatonin against oxidative stress.This article is protected by copyright. All rights reserved.
Article
Melatonin and its metabolites including 6-hydroxymelatonin (6(OH)M), N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) and 5-methoxytryptamine (5MT) are endogenously produced in human epidermis. This production depends on race, gender and age. The highest melatonin levels are in young African-Americans [30-50 years old (yo)], old Caucasian males (60-90 yo) and Caucasian females. AFMK levels are the highest in Caucasians males, while 6(OH)M and 5MT levels are similar in all groups. Testing of their phenotypic effects in normal human melanocytes show that melatonin and its metabolites (10(-5) M) inhibit tyrosinase activity and cell growth, and inhibit DNA synthesis in a dose dependent manner with 10(-9) M being the lowest effective concentration. In melanoma cells, they inhibited cell growth but had no effect on melanogenesis, except for 5MT which enhanced L-tyrosine induced melanogenesis. In conclusion, melatonin and its metabolites [6(OH)M, AFMK and 5MT] are produced endogenously in human epidermis and can affect melanocyte and melanoma behavior.
Article
The present study investigated the impact of solar UV radiation on ZnO nanoparticle toxicity through photocatalytic ROS generation and photo-induced dissolution. Toxicity of ZnO nanoparticles to Daphnia magna was examined under laboratory light versus simulated solar UV radiation (SSR). Photocatalytic ROS generation and particle dissolution were measured on a time-course basis. Two toxicity mitigation assays using CaCl2 and N-acetylcysteine were performed to differentiate the relative importance of these two modes of action. Enhanced ZnO nanoparticle toxicity under SSR was in parallel with photocatalytic ROS generation and enhanced particle dissolution. Toxicity mitigation by CaCl2 to a less extent under SSR than under lab light demonstrates the role of ROS generation in ZnO toxicity. Toxicity mitigation by N-acetylcysteine under both irradiation conditions confirms the role of particle dissolution and ROS generation. These findings demonstrate the importance of considering environmental solar UV radiation when assessing ZnO nanoparticle toxicity and risk in aquatic systems.
Article
The purpose of this study was to compare the transdermal permeation of a model compound, diclofenac diethylamine, from a hydrophilic and lipophilic vehicle across in vitro models simulating compromised skin. Mineral oil served as a lipophilic vehicle while 10mM phosphate buffered saline served as a hydrophilic vehicle. Compromised skin was simulated by tape stripping, delipidization, or microneedle application and compared with intact skin as a control. Transepidermal water loss was measured to assess barrier function. Skin compromised with tape stripping and delipidization significantly (p <0.05) increased permeation of diclofenac diethylamine compared to intact and microneedle treated skin with phosphate buffered saline vehicle. A similar trend in permeation was observed with mineral oil as the vehicle. For both vehicles, permeation across skin increased in the same order and correlated with degree of barrier impairment as indicated by transepidermal water loss values: intact < microneedles < tape stripping < delipidization. A study with hairless rats comparing both vehicles found the same trend, with hydrophilic vehicle having greater delivery. In conclusion, phosphate buffered saline vehicle resulted in higher permeation into and across skin compared to mineral oil vehicle for all simulated models of compromised skin.
Article
Possible interactions of melatonin with concurrently administered drugs were investigated in in vitro studies utilising human hepatic post-mitochondrial preparations; similar studies were conducted with rat preparations to ascertain whether rat is a suitable surrogate for human. Drugs were selected based not only on the knowledge that the 6-hydroxylation of exogenous melatonin, its principal pathway of metabolism, is mainly mediated by hepatic CYP1A2, but also on the likelihood of the drug being concurrently administered with melatonin. Hepatic preparations were incubated with either melatonin or 6-hydroxymelatonin in the presence and absence of a range of concentrations of interacting drug, and the production of 6-sulphatoxymelatonin monitored using a radioimmunoassay procedure. Of the drugs screened, only the potent CYP1A2 inhibitor 5-methoxypsoralen impaired the 6-melatonin hydroxylation at pharmacologically relevant concentrations, and is likely to lead to clinical interactions; diazepam, tamoxifen and acetaminophen (paracetamol) did not impair the metabolic conversion of melatonin to 6-sulphatoxymelatonin at concentrations attained following therapeutic administration. 17-Ethinhyloestradiol appeared not to suppress the 6-hydroxylation of melatonin but inhibited the sulphation of 6-hydroxymelatonin, but this is unlikely to result in an interaction following therapeutic intake of the steroid. Species differences in the inhibition of melatonin metabolism in human and rat hepatic post-mitochondrial preparations were evident implying that the rat may not be an appropriate surrogate of human in such studies.
Ultraviolet (UV) radiation is the main etiologic factor for skin cancer. The endogenous hormone melatonin has been proposed to have protective effects against sunlight. The aim of this review was to evaluate melatonin's protective effects against UV radiation and to clarify the cellular mechanisms behind this effect. Medline, Embase and Cinahl were searched up to January 2013 to identify studies evaluating melatonin's protective effect against UV radiation (UVR) induced skin erythema in humans and damage on a cellular level. Four human studies have investigated melatonin's protective effect on UVR induced skin damage. Melatonin was shown to have protective effects when applied before UVR, but no effect if applied after exposure. A total of 16 experimental studies evaluated melatonin's protective effect against UVR induced damage to cellular structures and pathways. The protection against UVR induced skin damage was conducted by melatonin acting directly as an antioxidant, and indirectly by regulating gene expression and inducing a DNA stabilizing effect. As these results were obtained using artificial UVR and without investigating possible side effects, studies using natural sunlight and evaluating possible side effects of topical melatonin administration are warranted.
Article
Biodegradable and biocompatible o/w emulsions were prepared using triglyceride oil and solid organic particles made of block copolymer nanoparticles as stabilizers (Pickering emulsions). In order to reach high concentration of internal phase, rather concentrated dispersions of nanoparticles were required. Nanoparticles of poly(caprolactone)-block-poly(ethylene oxide) (PCL-b-PEO) diblock copolymer were obtained using the “nanoprecipitation” process relying of the spontaneous emulsification upon solvent shifting. The classical “nanoprecipitation” process was improved so as to afford more concentrated suspensions of nanoparticles, and the nanoparticles were characterized by means of dynamic light scattering and 1H NMR spectroscopy. The process allowed the preparation of aqueous dispersions of PCL-b-PEO nanoparticles with 35–50 nm diameter at concentrations over 5 wt.%. In D2O, the PCL blocks formed a central hydrophobic core of reduced mobility, while the PEO blocks formed a hydrophilic corona layer swollen by water. O/w emulsions of medium chain triglycerides were successfully prepared using the suspensions of PCL-b-PEO nanoparticles as stabilizers. Typical droplet sizes were between 2 μm and 15 μm. The emulsions showed great stability upon storage and their particle size distributions did not show excess nanoparticles present in the aqueous phase as submicron nanoparticles, even when large amounts of nanoparticles with respect to oil were used. The mean droplet diameter of emulsions was controlled by the mass ratio M(oil)/M(nanoparticles). SANS and TEM experiments performed on PCL-b-PEO nanoparticles and micelle-stabilized emulsions disclosed a rearrangement of the nanoparticles at the oil/water interface due to the liquid state of the micelle core of PCL.
Article
Sun exposure is responsible for long term clinical skin changes such as photoaging, photodamage and photocancers. UVA wavelengths stimulate the production of reactive oxygen species (ROS) mainly causing photoaging. To protect against oxidative stress, skin cells developed several defense systems, including ROS and metal ion scavengers and a battery of detoxifying, heme degrading and repair enzymes. Melatonin's antioxidant activity is the result of three different but complementary actions: a) a direct action that is due to its ability to act as a free radical scavenger, b) an indirect action which is a consequence of melatonin's ability to reduce free radical generation (radical avoidance) and, c) its ability to up-regulate antioxidant enzymes. In this study, we focused our attention on prevention of photodamage, choosing melatonin as an antioxidant agent. In the present study was to analyze the effects of pre-treatment of murine fibroblasts cells (NIH3T3) with melatonin (10(-3) M) followed by UVA radiation (15 J/cm(2) ). Thereafter, changes in components of the extracellular matrix and in some antioxidant enzymes (inducible and constitutive heme oxygenase) were evaluated. We observed that UVA radiation caused altered expression of extracellular matrix protein and induced the expression of the inducible heme oxygenase. This increase was not sufficient to protect the cells from damage. Instead, melatonin pre-treatment led to a rise in increased heme degrading enzyme expression and a suppression of UVA-induced photodamage. These results suggest that melatonin, as a modifier of the dermato-endocrine system, may have utility in reducing skin aging. This article is protected by copyright. All rights reserved.
Article
Skin is the largest body organ forming a metabolically active barrier between external and internal environments. The metabolic barrier is composed of cytochromes P450 (CYPs) that regulate its homeostasis through activation or inactivation of biologically relevant molecules. In this review we focus our attention on local steroidogenic and secosteroidogenic systems in relation to skin cancer, e.g., prevention, attenuation of tumor progression and therapy. The local steroidogenic system is composed of locally expressed CYPs involved in local production of androgens, estrogens, gluco- and mineralo-corticosteroids from cholesterol (initiated by CYP11A1) or from steroid precursors delivered to the skin, and of their metabolism and/or inactivation. Cutaneous 7-hydroxylases (CYP7A1, CYP7B1 and CYP39) potentially can produce 7-hydroxy/oxy-steroids/sterols with modifying effects on local tumorigenesis. CYP11A1 also transforms 7-dehydrocholesterol (7DHC)→22(OH)7DHC→20,22(OH)2-7DHC→7-dehydropregnenolone, which can be further metabolized to other 5,7- steroidal dienes. These 5,7-dienal intermediates are convertedby ultraviolet radiation B (UVB) into secosteroids which show pro-differentiation and anti-cancer properties. Finally, the skin is the site of activation of vitamin D3 through two alternative pathways. The classical one involves sequential hydroxylation at positions 25 and 1 to produce active 1,25(OH)2D3, which is further inactivated through hydroxylation at C24. The novel pathway is initiated by CYP11A1 with predominant production of 20(OH)D3 which is further metabolized to biologically active but non-calcemic D3-hydroxyderivatives. Classical and non-classical (novel) vitamin D analogs show pro-differentiation, anti-proliferative and anticancer properties. In addition, melatonin is metabolized by local CYPs. In conclusion cutaneously expressed CYPs have significant effects on skin physiology and pathology trough regulation of its chemical milieu.
Chapter
IntroductionPhysicochemical propertiesExposure considerationsSummaryReferences
Article
Due to the increased demand for reliable data regarding penetration into and permeation across human skin, assessment of the absorption of xenobiotics has been gaining in importance steadily. In vitro experiments allow for determining these data faster and more easily than in vivo experiments. However, the experiments described in literature and the subsequent evaluation procedures differ considerably. Here we will give an overview on typical finite and infinite dose experiments performed in fundamental research and on the evaluation of the data. We will point out possible difficulties that may arise and give a short overview on attempts at predicting skin absorption in vitro and in vivo.
Article
Melatonin (N-acetyl-5-methoxytryptamine) is a hormone with multiple functions in humans, produced by the pineal gland and stimulated by β-adrenergic receptors. Serum melatonin levels exhibit a circadian rhythm with low levels during the day, rise in the evening and maximum levels at night between 2 and 4 a.m.. Melatonin participates in the regulation of several physiological processes such as seasonal biological rhythm, daily sleep induction, aging and modulation of immunobiological defence reactions. Furthermore, melatonin has a highly lipophilic molecular structure facilitating penetration of cell membranes and serving as an extra- and intracellular free radical scavenger. Melatonin seems to quench mainly hydroxyl radicals, the most damaging of all free radicals. Melatonin may play a role in the etiology and treatment of several dermatoses e.g. atopic eczema, psoriasis and malignant melanoma. The influence of melatonin on hair growth is another aspect. Topical application of melatonin inhibits the development of UV-erythema. Penetration through skin after topical application and oral bioavailability auxit further investigations on the pharmacokinetic and pharmacodynamic actions of melatonin.
Article
Many of melatonin's actions are mediated through interaction with the G-protein coupled membrane bound melatonin receptors type 1 and type 2 (MT1 and MT2, respectively) or, indirectly with nuclear orphan receptors from the RORα/RZR family. Melatonin also binds to the quinone reductase II enzyme, previously defined the MT3 receptor. Melatonin receptors are widely distributed in the body; herein we summarize their expression and actions in non-neural tissues. Several controversies still exist regarding, for example, whether melatonin binds the RORα/RZR family. Studies of the peripheral distribution of melatonin receptors are important since they are attractive targets for immunomodulation, regulation of endocrine, reproductive and cardiovascular functions, modulation of skin pigmentation, hair growth, cancerogenesis, and aging. Melatonin receptor agonists and antagonists have an exciting future since they could define multiple mechanisms by which melatonin modulates the complexity of such a wide variety of physiological and pathological processes.
Article
Chitosan is one of the most promising polymers for drug delivery through the mucosal routes because of its polycationic, biocompatible, and biodegradable nature, and particularly due to its mucoadhesive and permeation-enhancing properties. Bile salts are known to interact with lipid membranes, increasing their permeability. The addition of bile salts to chitosan matrices may improve the delivery characteristics of the system, making it suitable for mucosal administration of bioactive substances. In the present study we have developed chitosan nanoparticles using sodium deoxycholate as a counter ion and evaluated their potential as gene delivery carriers. Chitosan-sodium deoxycholate nanoparticles (CS/DS) obtained via a mild ionic gelation procedure using different weight ratios were used to encapsulate plasmid DNA (pDNA) expressing a "humanized" secreted Gaussia Luciferase as reporter gene (pGLuc, 5.7 kDa). Mean particle size, polydispersity index and zeta potential were evaluated in order to select the best formulation for further in vitro studies. The nanoparticles presented an average size of 153-403 nm and a positive zeta potential ranging from +33.0 to +56.9 mV, for nanoparticles produced with CS/DS ratios from 1:4 to 1:0.6 (w:w), respectively. The pDNA was efficiently encapsulated and AFM studies showed that pDNA-loaded nanoparticles presented a more irregular surface due to the interaction between cationic chitosan and negatively charged pDNA which results in a more compact structure when compared to empty nanoparticles. Transfection efficiency of CS/DS-pDNA nanoparticles into moderately (AGS) and well differentiated (N87) gastric adenocarcinoma cell lines was determined by measuring the expression of luciferase, while cell viability was assessed using the MTT reduction. The CS/DS nanoparticles containing encapsulated pDNA were able to transfect both AGS and N87 cell lines, being more effective with AGS cells, the less differentiated cell line. The highest enzymatic activity was achieved with 20% pDNA encapsulated and after 24 h of transfection time. Low cytotoxicity was observed for the CS/DS nanoparticles either with or without pDNA, suggesting this could be a new potential vehicle for mucosal delivery of pDNA.
Article
Oryzalin is a dinitroaniline drug that has attracted recent interest for the treatment of leishmaniasis. Its use as an antiparasitic therapeutic agent is limited by the low water solubility associated with an in vivo rapid clearance, leading to the administration of larger and possibly toxic doses in in vivo studies, and the use of solvents that may lead to undesirable side effects. In the present work oryzalin-containing lipid nanoparticles were produced by a emulsion-solvent evaporation technique using a composition suitable for parenteral administration, i.e., tripalmitin (solid lipid) and a complex mixture of three emulsifying agents (soya lecithin, Tween® 20 and sodium deoxycholate). Physicochemical characterization included the determination of mean particle size, polydispersity index, zeta potential, encapsulation efficiency and DSC studies. Final formulations revealed values of <140 nm (PI<0.2) and zeta potential of ≈-35 mV, as well as encapsulation efficiency >75%. The effects of various processing parameters, such as lipid and surfactant and composition and concentration, as well as the stability during the harsh procedures of autoclaving (121°C/15 min) and freeze-drying were also evaluated. Formulations revealed to be stable throughout freeze-drying and moist-heath sterilization without significant variations on physicochemical properties and no significant oryzalin losses. The use of a complex surfactant mixture proved crucial for preserving formulation stability. Particularly, lecithin appears as a key component in the stabilization of tripalmitin-based oryzalin-containing lipid nanoparticles. Finally, cell viability studies demonstrated that the incorporation of oryzalin in nanoparticles decreases cytotoxicity, thus suggesting this strategy may improve tolerability and therapeutic index of dinitroanilines.
Article
Over the past several decades, there has been increasing interest in understanding the roles of the immune system in the development and progression of cancer. The importance of the immune system in human skin cancer has been long recognized based primarily upon the increased incidence of skin cancers in organ transplant recipients and mechanisms of ultraviolet (UV) radiation-mediated immunomodulation. In this review, we integrate multiple lines of evidence highlighting the roles of the immune system in skin cancer. First, we discuss the concepts of cancer immunosurveillance and immunoediting as they might relate to human skin cancers. We then describe the clinical and molecular mechanisms of skin cancer development and progression in the contexts of therapeutic immunosuppression in organ transplant recipients, viral oncogenesis, and UV radiation-induced immunomodulation with a primary focus on basal cell carcinoma and squamous cell carcinoma. The clinical evidence supporting expanding roles for immunotherapy is also described. Finally, we discuss recent research examining the functions of particular immune cell subsets in skin cancer and how they might contribute to both antitumour and protumour effects. A better understanding of the biological mechanisms of cancer immunosurveillance holds the promise of enabling better therapies.
Article
Ethanol is synergistic with tobacco in HNSCC carcinogenesis. While ethanol or tobacco, alone, increases the risk of HNSCC 2- to 6-fold, this risk increases to 50-fold with both ethanol and tobacco. Reactive oxygen species (ROS) has been implicated in numerous cellular processes associated with malignancy, including enhancement of cell proliferation, DNA damage, and cell migration. Objectives: To understand how alcohol contributes synergistically, with tobacco consumption, to HNSCC malignancy, we studied the effects of alcohol on ROS induction of and on the migration of HNSCC. Study Design: Using normal HaCaT and transformed HaCaT II-4 human keratinocyte cell lines, we determined the effect of alcohol exposure on ROS level and on cell migration. Methods: ROS was determined by intracellular fluorescence quantification via NIS Elements AR 3.0 imaging software and by fluorescence activated cell sorting (FACS). Migration was determined by the Fluoroblok transwell assay. Results: The transformed HaCaT II-4 cells had a greater basal level of ROS than the normal HaCaT cells. While both cell lines showed significant increase in ROS when exposed to 8% ethanol, When compared to normal HaCaT cells, the transformed HaCaT II-4 cells showed a 50.7% greater ROS level. (mean fluorescence: HaCaT II-4 = 6.95; HaCaT = 4.61). Exposure to 8% ethanol significantly increased the migration of transformed HaCaT-II4 cells, while having little effect on normal HaCaT cell migration. Conclusions: The oral mucosa of smokers contains a mixture of normal and transformed keratinocytes, as a result of the mutagenic effects of tobacco. Our results suggest that alcohol preferentially enhances an invasive phenotype in transformed keratinocytes over normal keratinocytes by inducing ROS. Copyright © 2010 The American Laryngological, Rhinological, and Otological Society, Inc.
Article
Solid organ transplant and subsequent graft survival have increased worldwide, while immunosuppression has prevented rejection with increasing success. Side effects of cutaneous infection and neoplasm, however, affect the majority of solid organ transplant recipients (OTRs). Squamous cell carcinoma of the skin (SCC) is the most common neoplasm overall following organ transplant with a risk that is 60-100 times greater than for the immunocompetent population. This review focuses on questions of ongoing debate about SCC formation in OTRs such as viral carcinogenesis, systemic photoprotection, photosensitization by drugs, the impact of immunosuppressive drugs and inflammation as a driver of carcinogenesis.
Article
Predictive tests are of value in forecasting the response of a population to a sensitizer; diagnostic testing is used to determine what substances may actually be producing dermatologic problems. Skin sensitization predictive and diagnostic data for the eleven most frequently encountered skin sensitizers in Western Europe, Canada and the United States are reviewed. These compounds include two drugs (benzocaine and neomycin), two cosmetic ingredients (p-phenylenediamine and balsam of Peru), four preservatives (formaldehyde, ethylenediamine, parabens and mercurials) and three ingredients of wearing apparel (nickel, chromium and thiram). Many of the data were collected by the North American Contact Dermatitis Group and the International Contact Dermatitis Research Group on tests with 1,200 and 4,825 dermatologic patients, respectively; the remainder were obtained by individual investigators with smaller groups of subjects. The data obtained by various investigators are discussed in relation to the factors which affect the extent and degree of sensitization which they can cause.
Article
Published permeability coefficient (K p) data for the transport of a large group of compounds through mammalian epidermis were analyzed by a simple model based upon permeant size [molecular volume (MV) or molecular weight (MW)] and octanol/water partition coefficient (K oct). The analysis presented is a facile means to predict the percutaneous flux of pharmacological and toxic compounds solely on the basis of their physicochemical properties. Furthermore, the derived parameters of the model have assignable biophysical significance, and they provide insight into the mechanism of molecular transport through the stratum corneum (SC). For the very diverse group of chemicals considered, the results demonstrate that SC intercellular lipid properties alone are sufficient to account for the dependence of K p upon MV (or MW) and K oct. It is found that the existence of an “aqueous-polar (pore) pathway” across the SC is not necessary to explain the K p values of small, polar nonelectrolytes. Rather, their small size, and consequently high diffusivity, accounts for their apparently larger-than-expected K p. Finally, despite the size and breadth of the data set (more than 90 compounds with MW ranging from 18 to >750, and log K oct ranging from −3 to + 6), the postulated upper limiting value of K p for permeants of very high lipophilicity cannot be determined. However, the analysis is able to define the physicochemical characteristics of molecules which should exhibit these maximal K p values. Overall, then, we present a facile interpretation of a considerable body of skin permeability measurements that (a) very adequately describes the dependence of K p upon permeant size and lipophilicity, (b) generates parameters of considerable physicochemical and mechanistic relevance, and (c) implies that the SC lipids alone can fully characterize the barrier properties of mammalian skin.
Article
Stimulation of the oxidative metabolic burst of human polymorphonuclear leukocytes (PMNL) may occur by an all-or-none trigger mechanism or by a graded response to increasing stimulation of an individual cell. If the proposed all-or-none mechanism occurred during phagocytosis, a PMNL would expend all of its metabolic potential at once, yet PMNL can proceed to ingest multiple organisms. This study employed dual laser flow cytometry to correlate the number of cell-associated organisms with oxidative product formation in individual PMNL. Intracellular oxidation of nonfluorescent 2',7'-dichlorofluorescein (DCFH) to highly fluorescent 2',7'-dichlorofluorescein (DCF) provided a quantitative assay of H2O2-dependent oxidative product formation generated by the cell's oxidative metabolic burst. Staphylococcus aureus were fixed and stained with Texas red to allow simultaneous monitoring of bacteria (red fluorescence, greater than 580 nm) and DCF (green fluorescence, 510 to 550 nm) content of each cell. Computer correlation of bacterial and DCF fluorescence allowed determination of the DCF formation by PMNL containing specific numbers (0 to 15) of bacteria. Oxidative product formation was directly related to the number of bacteria ingested in a time-dependent manner (mean per cell of 6.4, 12.8, 19.1, and 24.4 attomoles (amol) DCF formed per cell per bacterium after 15, 30, 45, and 60 min, respectively. Opsonization of bacteria with fresh normal serum (primarily C3b opsonization) or with specific IgG demonstrated qualitatively similar responses, except that the response per IgG-opsonized organism was, on the average, more than twice the response to bacteria opsonized with serum. Thus, sequential phagocytosis of multiple bacteria elicits an incremental oxidative response of human PMNL.
Article
Melatonin is being increasingly promoted as a treatment for "jet lag" and insomnia and has been suggested to act as an antioxidant in vivo. The antioxidant and potential pro-oxidant activities of melatonin were investigated in vitro. Melatonin was able to scavenge hypochlorous acid (HOCl) at a rate sufficient to protect catalase against inactivation by this molecule. Melatonin could also prevent the oxidation of 5-thio-2-nitrobenzoic acid by HOCl. Melatonin decreased the peroxidation of ox-brain phospholipids with a calculated IC50 of (210 +/- 2.3) microM. In contrast, serotonin which also scavenged HOCl, was much more effective in decreasing phospholipid peroxidation (IC50 15 +/- 5 microM). Both compounds reacted with trichloromethylperoxyl radical (CCl3O2) with rate constants of (2.7 +/- 0.2) x 10(8) and (1.2 +/- 0.1) x 10(8)M-1 s- respectively. Melatonin did not scavenge superoxide radical and weakly protected DNA against damage by the ferric bleomycin system. By contrast serotonin was weakly pro-oxidant in the ferric-bleomycin system and strongly pro-oxidant in the Fe(3+)-EDTA/H2O-deoxyribose system. Solubility restrictions precluded examination of melatonin in this system. Our data show that melatonin exerts only limited direct antioxidant activities.
Article
Melatonin's actions in organisms are more widespread than originally envisaged. Over three decades ago, the changing pattern of nocturnal melatonin production was found to be the signal for the annual cycle of reproduction in photoperiodic species. Since then, melatonin's actions also have been linked to circadian rhythms, immune function, sleep, retinal physiology and endocrine functions in general. In recent years, however, the sphere of influence of melatonin was further expanded when the indole was found to be an effective free radical scavenger and antioxidant. Free radicals are toxic molecules, many being derived from oxygen, which are persistently produced and incessantly attack and damage molecules within cells; most frequently this damage is measured as peroxidized lipid products, carbonyl proteins, and DNA breakage or fragmentation. Collectively, the process of free radical damage to molecules is referred to as oxidative stress. Melatonin reduces oxidative stress by several means. Thus, the indole is an effective scavenger of both the highly toxic hydroxyl radical, produced by the 3 electron reduction of oxygen, and the peroxyl radical, which is generated during the oxidation of unsaturated lipids and which is sufficiently toxic to propagate lipid peroxidation. Additionally, melatonin may stimulate some important antioxidative enzymes, i.e., superoxide dismutase, glutathione peroxidase and glutathione reductase. In in vivo tests, melatonin in pharmacological doses has been found effective in reducing macromolecular damage that is a consequence of a variety of toxic agents, xenobiotics and experimental paradigms which induce free radical generation. In these studies, melatonin was found to significantly inhibit oxidative damage that is a consequence of paraquat toxicity, potassium cyanide administration, lipopolysaccharide treatment, kainic acid injection, carcinogen administration, carbon tetrachloride poisoning, etc., as well as reducing the oxidation of macromolecules that occurs during strenuous exercise or ischemia-reperfusion. In experimental models which are used to study neurodegenerative changes associated with Alzheimer's and Parkinson disease, melatonin was found to be effective in reducing neuronal damage. Its lack of toxicity and the ease with which melatonin crosses morphophysiological barriers and enters subcellular compartments are essential features of this antioxidant. Thus far, most frequently pharmacological levels of melatonin have been used to combat oxygen toxicity. The role of physiological levels of melatonin, which are known to decrease with age, is being investigated as to their importance in the total antioxidative defense capacity of the organism.
Both genetic (intrinsic) and environmental (extrinsic) factors contribute to the phenotypic changes in cutaneous aging. However, only recently have the underlying molecular mechanisms involved in these changes been elucidated. DNA damage to both genomic and mitochondrial DNA and subsequent DNA repair contribute greatly to age-associated skin changes and carcinogenesis. Better understanding of these intricate, interwoven mechanisms involved in DNA damage and repair might help to develop new strategies in preventing and treating changes of intrinsic skin aging and photoaging, improving skin appearance and reducing the risk of skin cancer.
Article
Major photoproducts induced by carcinogenic ultraviolet (UV) radiation are the cylobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4) photoproducts (6-4 PPs). 8-Hydroxy-2 -deoxyguanosine (8-OHdG) is also a DNA base-modified product generated by reactive oxygen species in conditions of ultraviolet stress, Although UVB-induced CPDs and 6-4 PPs have been investigated in animal and human skin, little is known about the role of 8-OHdG in UVB-induced human skin damage or carcinogenesis. Normal human skin from three volunteers was exposed to UV radiation, and the time course of induction and removal of 8-OHdG was examined by immunohistochemical analysis with catalysed signal amplification on formalin-fixed paraffin sections. Formation of CPDs and 6-4 PPs was also examined by immunostaining on the same skin specimens. Control epidermis with no exposure to UV radiation showed little nuclear staining of 8-OHdG, but an increased level of 8-OHdG was clearly observed in epidermis biopsied after irradiation. Induced 8-OHdG can rapidly be removed from nucleus during the first 24-48 h, as the staining intensity diminished gradually, almost reaching the control level by 72-96 h after irradiation. Staining for CPDs or 6-4 PPs revealed induction of these photoproducts in human skin, although 6-4 PP-positive cells disappeared more rapidly than those that stained for CPDs or 8-OHdG. Together with protective effect of antioxidants, our results indicate that not only CPDs and 6-4 PPs but also 8-OHdG may play a significant part in UV carcinogenesis.
Article
Human skin has unique properties of which functioning as a physicochemical barrier is one of the most apparent. The human integument is able to resist the penetration of many molecules. However, especially smaller molecules can surpass transcutaneously. They are able to go by the corneal layer, which is thought to form the main deterrent. We argue that the molecular weight (MW) of a compound must be under 500 Dalton to allow skin absorption. Larger molecules cannot pass the corneal layer. Arguments for this "500 Dalton rule" are; 1) virtually all common contact allergens are under 500 Dalton, larger molecules are not known as contact sensitizers. They cannot penetrate and thus cannot act as allergens in man; 2) the most commonly used pharmacological agents applied in topical dermatotherapy are all under 500 Dalton; 3) all known topical drugs used in transdermal drug-delivery systems are under 500 Dalton. In addition, clinical experience with topical agents such as cyclosporine, tacrolimus and ascomycins gives further arguments for the reality of the 500 Dalton rule. For pharmaceutical development purposes, it seems logical to restrict the development of new innovative compounds to a MW of under 500 Dalton, when topical dermatological therapy or percutaneous systemic therapy or vaccination is the objective.
Article
The photostability of melatonin, a hormone used as supplementary drug in the alleviation of jet-lag and other sleep disorders, was studied. The drug photodegradation at different pH values was monitored by HPLC methods. The main photoproduct was isolated and characterised on the basis of the NMR, FTIR, and mass spectra. A HPLC method, in combination with a post-column on-line photochemical derivatisation was developed for the selective and reliable quality control of commercially available melatonin containing products.