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Caracterização do potencial dermatológico de exopolissacarídeos extraídos de dinoflagelados marinhos
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A pele humana é reconhecida por desempenhar funções vitais de proteção e regulação do organismo. No entanto, atualmente, a pele é vista não apenas como uma barreira biológica, mas também como um reflexo de saúde, vitalidade e beleza, estando associada ao estatuto social em sociedades desenvolvidas, o que tem impulsionado o elevado crescimento da indústria cosmética.
Os organismos marinhos destacam-se como fontes excecionais de novas moléculas bioativas, uma vez que se desenvolvem em habitats sujeitos a condições de stress variáveis, o que estimula a produção de metabolitos secundários com elevado potencial biológico. Assim, ingredientes de origem marinha têm ganho destaque pela diversidade de compostos com potencial para promover a regeneração celular, prevenir o envelhecimento e proteger a barreira cutânea, constituindo alternativas seguras e eficazes face a diversos ingredientes sintéticos. Deste modo, o objetivo da presente dissertação consistiu em avaliar o potencial dermatológico de exopolissacarídeos (EPS) extraídos de três dinoflagelados marinhos: Protoceratium reticulatum, Gymnodinium catenatum e Prorocentrum lima.
As amostras de EPS foram obtidas através de sucessivas centrifugações do meio de crescimento dos dinoflagelados, seguidas da precipitação do sobrenadante com etanol absoluto, diálise do pellet resultante e posterior liofilização. A caracterização química incluiu a quantificação de constituintes frequentemente associados a potenciais interferências ou propriedades bioativas, nomeadamente polifenóis, proteínas, sulfatos e ácidos nucleicos. Esta caracterização foi complementada pela análise do perfil químico das amostras por espectroscopia de infravermelho com transformada de Fourier (FTIR) e por espectroscopia de ressonância magnética nuclear de protão (¹H RMN). Paralelamente, foram realizados diferentes ensaios in vitro com o objetivo de avaliar o potencial dermatológico dos EPS, nomeadamente: i) capacidade antioxidante [redução do radical 2,2-difenil-1-picrilhidrazilo (DPPH), do radical superóxido (O₂•⁻) e do ião férrico (FRAP)]; ii) atividade anti-enzimática (colagenase, elastase, hialuronidase e tirosinase); iii) atividade antimicrobiana contra alguns microrganismos da microbiota da pele (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis e Cutibacterium acnes); iv) efeito fotoprotetor (produção de espécies reativas de oxigénio-ROS) e, v) atividade anti-inflamatória (níveis de óxido nítrico-NO).
A análise por FTIR dos EPS obtidos evidenciou a presença de grupos funcionais caraterísticos de açúcares bem como a presença de grupos sulfato, enquanto a análise por ¹H RMN sugeriu a predominância de ligações β-glicosídicas entre os vários monómeros de açúcares, alguns possuindo grupos metilo. Quanto à presença de outros metabolitos, não foram detetados teores quantificáveis de proteínas e de polifenóis, sendo que, a quantificação de ácidos nucleicos revelou apenas níveis residuais.
De um modo geral, os EPS não evidenciaram uma capacidade antioxidante relevante. Nos ensaios anti-enzimáticos, também não apresentaram atividade inibitória sobre as enzimas colagenase e hialuronidase, mas inibiram significativamente a atividade da elastase (P. reticulatum ≈ 15%) e da tirosinase (G. catenatum ≈ 18%). Quanto à atividade antimicrobiana, os EPS das espécies G. catenatum e P. lima reduziram o crescimento de S. aureus em cerca de 8%, sendo a espécie P. lima a que exibiu uma maior atividade antimicrobiana sobre a bactéria S. hominis, inibindo o seu crescimento em cerca de 12%. Relativamente ao potencial fotoprotetor em células HaCaT expostas a radiação UVA-B, nenhum EPS reduziu significativamente a produção de ROS nas concentrações sub-tóxicas testadas. Por sua vez, a análise do efeito anti-inflamatório em células RAW 264.7 mostrou reduções significativas na produção de NO quando induzida a inflamação através do tratamento com lipopolissacarídeos (LPS). Os EPS de P. reticulatum destacaram-se por reduzirem em cerca de 30% a produção de NO em todas as concentrações testadas (100, 300 e 1000 μg/mL), enquanto G. catenatum revelou efeito apenas a 100 μg/mL (25% de inibição). Destacaram-se os EPS de P. lima, que foram capazes de reduzir a produção de NO em mais de 40% a 300 μg/mL.
Em síntese, os resultados indicam que os EPS dos dinoflagelados estudados apresentam propriedades seletivas com relevância para incorporação em formulações cosméticas, particularmente no controlo da degradação da elastina, regulação da síntese de melanina e modulação da resposta inflamatória.
Human skin is recognized for its vital protective and regulatory functions within the body. However, it is now regarded not only as a biological barrier but also as a reflection of health, vitality, and beauty, being associated with social status in developed societies, which has driven a remarkable growth of the cosmetic industry. Marine organisms stand out as exceptional sources of novel bioactive molecules, as they thrive in habitats exposed to variable stress conditions, which stimulate the production of secondary metabolites with high biological potential. Consequently, marine-derived ingredients have gained attention for their chemical diversity and their potential to promote cell regeneration, prevent skin aging, and protect the skin barrier, providing safe and effective alternatives to various synthetic ingredients. In this context, the aim of this dissertation was to evaluate the dermatological potential of exopolysaccharides (EPS) extracted from three marine dinoflagellates: Protoceratium reticulatum, Gymnodinium catenatum, and Prorocentrum lima. EPS samples were obtained through successive centrifugations of the dinoflagellate culture medium, followed by precipitation of the supernatant with absolute ethanol, dialysis of the resulting pellet, and subsequent lyophilization. Chemical characterization included the quantification of components often associated with potential interferences or bioactive properties, namely polyphenols, proteins, sulphates, and nucleic acids. This characterization was complemented by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (¹H NMR). In parallel, different in vitro assays were carried out to assess the dermatological potential of EPS, namely: i) antioxidant capacity [reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide radical (O₂•⁻), and ferric ion (FRAP)]; ii) anti-enzymatic activity (collagenase, elastase, hyaluronidase, and tyrosinase); iii) antimicrobial activity against selected species of the skin microbiota (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis and Cutibacterium acnes); iv) photoprotective effect (reactive oxygen species-ROS production); and v) anti-inflammatory activity (nitric oxide-NO levels). FTIR analysis of the obtained EPS revealed the presence of characteristic functional groups of sugars as well as sulphate groups, while the ¹H-NMR analysis suggested the predominance of β-glycosidic linkages between sugar monomers, some bearing methyl groups. Regarding the presence of other metabolites, no significant levels of proteins or polyphenols were detected, while nucleic acids were only present at residual levels. Overall, the EPS did not exhibit relevant antioxidant capacity. In the anti-enzymatic assays, they also showed no significant activity against collagenase and hyaluronidase; however, they significantly inhibited elastase (P. reticulatum ≈ 15%) and tyrosinase (G. catenatum ≈ 18%). Regarding their antimicrobial activity, EPS from G. catenatum and P. lima reduced the growth of S. aureus by about 8%, while P. lima showed the highest antimicrobial activity against S. hominis, inhibiting its growth by approximately 12%. In terms of photoprotective potential in HaCaT cells exposed to UVA-B radiation, none of the EPS significantly reduced ROS production at the sub-toxic concentrations tested. Conversely, the analysis of anti-inflammatory activity in RAW 264.7 cells demonstrated significant reductions in NO production when inflammation was induced by lipopolysaccharide (LPS) treatment. P. reticulatum EPS stood out by reducing NO production by about 30% at all tested concentrations (100, 300, and 1000 μg/mL); G. catenatum showed an effect only at 100 μg/mL (25% inhibition), while P. lima EPS reduced NO production by more than 40%, at 300 μg/mL. In summary, the results indicate that the EPS from the studied dinoflagellates display selective properties with cosmetic relevance, particularly for controlling elastin degradation, regulating melanin synthesis, and modulating the inflammatory response.
Human skin is recognized for its vital protective and regulatory functions within the body. However, it is now regarded not only as a biological barrier but also as a reflection of health, vitality, and beauty, being associated with social status in developed societies, which has driven a remarkable growth of the cosmetic industry. Marine organisms stand out as exceptional sources of novel bioactive molecules, as they thrive in habitats exposed to variable stress conditions, which stimulate the production of secondary metabolites with high biological potential. Consequently, marine-derived ingredients have gained attention for their chemical diversity and their potential to promote cell regeneration, prevent skin aging, and protect the skin barrier, providing safe and effective alternatives to various synthetic ingredients. In this context, the aim of this dissertation was to evaluate the dermatological potential of exopolysaccharides (EPS) extracted from three marine dinoflagellates: Protoceratium reticulatum, Gymnodinium catenatum, and Prorocentrum lima. EPS samples were obtained through successive centrifugations of the dinoflagellate culture medium, followed by precipitation of the supernatant with absolute ethanol, dialysis of the resulting pellet, and subsequent lyophilization. Chemical characterization included the quantification of components often associated with potential interferences or bioactive properties, namely polyphenols, proteins, sulphates, and nucleic acids. This characterization was complemented by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (¹H NMR). In parallel, different in vitro assays were carried out to assess the dermatological potential of EPS, namely: i) antioxidant capacity [reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide radical (O₂•⁻), and ferric ion (FRAP)]; ii) anti-enzymatic activity (collagenase, elastase, hyaluronidase, and tyrosinase); iii) antimicrobial activity against selected species of the skin microbiota (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis and Cutibacterium acnes); iv) photoprotective effect (reactive oxygen species-ROS production); and v) anti-inflammatory activity (nitric oxide-NO levels). FTIR analysis of the obtained EPS revealed the presence of characteristic functional groups of sugars as well as sulphate groups, while the ¹H-NMR analysis suggested the predominance of β-glycosidic linkages between sugar monomers, some bearing methyl groups. Regarding the presence of other metabolites, no significant levels of proteins or polyphenols were detected, while nucleic acids were only present at residual levels. Overall, the EPS did not exhibit relevant antioxidant capacity. In the anti-enzymatic assays, they also showed no significant activity against collagenase and hyaluronidase; however, they significantly inhibited elastase (P. reticulatum ≈ 15%) and tyrosinase (G. catenatum ≈ 18%). Regarding their antimicrobial activity, EPS from G. catenatum and P. lima reduced the growth of S. aureus by about 8%, while P. lima showed the highest antimicrobial activity against S. hominis, inhibiting its growth by approximately 12%. In terms of photoprotective potential in HaCaT cells exposed to UVA-B radiation, none of the EPS significantly reduced ROS production at the sub-toxic concentrations tested. Conversely, the analysis of anti-inflammatory activity in RAW 264.7 cells demonstrated significant reductions in NO production when inflammation was induced by lipopolysaccharide (LPS) treatment. P. reticulatum EPS stood out by reducing NO production by about 30% at all tested concentrations (100, 300, and 1000 μg/mL); G. catenatum showed an effect only at 100 μg/mL (25% inhibition), while P. lima EPS reduced NO production by more than 40%, at 300 μg/mL. In summary, the results indicate that the EPS from the studied dinoflagellates display selective properties with cosmetic relevance, particularly for controlling elastin degradation, regulating melanin synthesis, and modulating the inflammatory response.
Descrição
Palavras-chave
Exopolissacarídeos Microalgas Dinoflagelados marinhos Atividades biológicas Envelhecimento da pele Stress oxidativo Microbiota da pele