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Research Project
Applied Molecular Biosciences Unit
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Publications
Comparative studies on the photoreactivity, efficacy, and safety of depigmenting agents
Publication . Mota, Sandra; Rosa, Gonçalo P.; Barreto, Maria Carmo; Garrido, Jorge; Sousa, Emília; Cruz, Maria T.; Almeida, Isabel F.; Quintas, Clara
Depigmenting products are increasingly used to counteract skin hyperpigmentation and related psychosocial issues. This study aimed to compare different depigmenting agents—4-butylresorcinol; bakuchiol; tranexamic acid; ascorbyl glucoside; α-arbutin; and ascorbic acid—for photoreactivity; tyrosinase inhibition; and safety. Photoreactivity was assessed using the Reactive Oxygen Species assay. In vitro tyrosinase inhibition was compared, and cell viability was assessed in B-16V melanocytes to evaluate safety. Results showed 4-butylresorcinol, ascorbyl glucoside, and α-arbutin are non-photoreactive, while for ascorbic acid and bakuchiol it was not possible to reach conclusive results due to the lack of specificity of the ROS assay. 4-Butylresorcinol, acting as a competitive inhibitor, displayed potent tyrosinase inhibition, followed by ascorbic acid and bakuchiol. Both 4-butylresorcinol and bakuchiol reduced cell viability in a concentration-dependent manner. The insights obtained in this work support the development of depigmenting products by providing useful scientific guidance on the photostability, tyrosinase inhibitory efficacy, and skin safety of depigmenting agents.
In Vitro Evaluation of the Photoreactivity and Phototoxicity of Natural Polyphenol Antioxidants
Publication . Aguiar, Brandon; Carmo, Helena; Garrido, Jorge; Sousa Lobo, José M.; Almeida, Isabel F.
Polyphenols are a large family of natural compounds widely used in cosmetic products due to their antioxidant and anti-inflammatory beneficial properties and their ability to prevent UV radiation-induced oxidative stress. Since these compounds present chromophores and are applied directly to the skin, they can react with sunlight and exert phototoxic effects. The available scientific information on the phototoxic potential of these natural compounds is scarce, and thus the aim of this study was to evaluate the photoreactivity and phototoxicity of five phenolic antioxidants with documented use in cosmetic products. A standard ROS assay was validated and applied to screen the photoreactivity of the natural phenolic antioxidants caffeic acid, ferulic acid, p-coumaric acid, 3,4-dihydroxyphenylacetic acid (DOPAC), and rutin. The phototoxicity potential was determined by using a human keratinocyte cell line (HaCaT), based on the 3T3 Neutral Red Uptake phototoxicity test. Although all studied phenolic antioxidants absorbed UV/Vis radiation in the range of 290 to 700 nm, only DOPAC was able to generate singlet oxygen. The generation of reactive oxygen species is an early-stage chemical reaction as part of the phototoxicity mechanism. Yet, none of the studied compounds decreased the viability of keratinocytes after irradiation, leading to the conclusion that they do not have phototoxic potential. The data obtained with this work suggests that these compounds are safe when incorporated in cosmetic products.
Design of an Emulgel for Psoriasis Focused on Patient Preferences
Publication . Oliveira, Rita Sanches; da Silva, Diva Ferraz; Mota, Sandra; Garrido, Jorge; Garrido, E. Manuela; Lobo, José Manuel Sousa; Almeida, Isabel Filipa
Adherence to topical treatments is low and is known to be influenced by the vehicle properties. Betamethasone dipropionate (BD) is an anti-inflammatory steroid, used in psoriasis treatment in the form of an ointment, cream, or solution. The aim of this work was to develop a new vehicle for BD, focusing on the preferences of patients with psoriasis as a strategy to improve treatment adherence. Two vehicles with an aqueous external phase were explored: an emulgel and a hydrogel based on a cyclodextrin inclusion complex used to improve the aqueous solubility of BD. Since BD solubilization was not fully achieved in the hydrogel, only the emulgel was selected for further characterization. This new vehicle (emulgel) is characterized by its white, shiny appearance and good spreading properties. In comparison with petrolatum, a lower residue, higher evaporation rate, lower stickiness, and reduced ability to stain polyester fabric were observed. This vehicle also showed shear thinning behavior. The impact of this new vehicle on adherence to topical treatments should be further confirmed in clinical settings.
Influence of temperature on the subcritical water extraction of Actinidia arguta leaves: A screening of pro-healthy compounds
Publication . Silva, Ana Margarida; Luís, Ana Sofia; Moreira, Manuela M.; Ferraz, Ricardo; Brezo-Borjan, Tanja; Švarc-Gajić, Jaroslava; Costa, Paulo C.; Delerue-Matos, Cristina; Rodrigues, Francisca
Actinidia arguta is a species disseminated in Europe and classified by the Chinese Herbal Medicine as a medicinal plant. The fruit (kiwiberry) has been extensively exploited for multiple purposes, while leaves where discarded. The objective of this study was to evaluate the optimal Subcritical Water Extraction (SWE) temperature (110 °C - 160 °C) of antioxidants and polyphenols from A. arguta leaves. The optimal temperature of extraction was 123 °C, revealing the highest phenolic and flavonoid contents and good scavenging efficiencies against HOCl (IC50 = 17.06 μg/mL) and O2●- (IC50 = 335.2 μg/mL), without toxicity on intestinal cells. The phenolic profile was characterized by high amounts of phenolic acids (e.g., gallic acids), flavanols (catechin) and flavonols (e.g., quercetin-3-O-galactoside). This work allows to conclude that SWE can be a useful extraction technique for the recovery of polyphenolics from A. arguta leaves
Development and Optimization of a Topical Formulation with Castanea sativa Shells Extract Based on the Concept “Quality by Design”
Publication . Oliveira, Nágilla; Cádiz-Gurrea, María de La Luz; Silva, Ana Margarida; Macedo, Catarina; Rodrigues, Francisca; Costa, Paulo
The proposed study aims to develop and optimize a topical formulation with Castanea sativa shells extract considering the concept of Quality by Design, focusing on a planned development that consider the vulnerabilities of the entire process through risk analysis tools and design of experiments (DoE). A Box–Behnken design with three factors and three levels was used as a statistical tool for the execution of the DoE and the analysis of the response surface methodology responses. The independent variables studied were the quantity of sodium lauryl sulfate (%) (X1), beeswax (%) (X2) and macadamia oil (%) (X3); the dependent variables were pH (Y1), viscosity (Y2) and adhesiveness (Y3). According to the mathematical model, the optimal formulation contains 0.93% of sodium lauryl sulfate, 5.00% of beeswax and 10.00% of macadamia oil. The optimal formulation with the extract was prepared and characterized over the time, regarding organoleptic and technological characteristics, allowing conclusions to be reached regarding its stability. The formulation presented a pleasant odor and was light brown in color, it also demonstrated pseudoplastic-thixotropic behavior and a small reduction in the formulation consistency after 30 days of storage. This study demonstrated the efficiency of the Quality by Design methodology to understand the product variability, supporting that this approach favors a better understanding of the whole process and enables to design a robust development stage, reducing costs and generating high-quality products
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
6817 - DCRRNI ID
Funding Award Number
UIDP/04378/2020