Biosystems and Integrative Sciences Institute

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Publications

Edible seaweeds extracts: characterization and functional properties for health conditions

Publication . Coelho, Mariana; Duarte, Ana Patrícia; Pinto, Sofia; Botelho, Hugo M.; Reis, Catarina; Serralheiro, Maria Luisa; Pacheco, Rita

Seaweeds are popular foods due to claimed beneficial health effects, but for many there is a lack of scientific evidence. In this study, extracts of the edible seaweeds Arame, Nori, and Fucus are compared. Our approach intends to clarify similarities and differences in the health properties of these seaweeds, thus contributing to target potential applications for each. Additionally, although Arame and Fucus seaweeds are highly explored, information on Nori composition and bioactivities is scarce. The aqueous extracts of the seaweeds were obtained by decoction, then fractionated and characterized according to their composition and biological activity. It was recognized that fractioning the extracts led to bioactivity reduction, suggesting a loss of bioactive compounds synergies. The Arame extract showed the highest antioxidant activity and Nori exhibited the highest potential for acetylcholinesterase inhibition. The identification of the bioactive compounds in the extracts allowed to see that these contained a mixture of phloroglucinol polymers, and it was suggested that Nori's effect on acetylcholinesterase inhibition may be associated with a smaller sized phlorotannins capable of entering the enzyme active site. Overall, these results suggest a promising potential for the use of these seaweed extracts, mainly Arame and Nori, in health improvement and management of diseases, namely those associated to oxidative stress and neurodegeneration.

2023-03-10Journal article

Open access

Synthesis and the in vitro evaluation of antitumor activity of novel thiobenzanilides

Publication . Álvaro Martins, Maria Joao; Railean, Violeta; Martins, Filomena; Machuqueiro, Miguel; Pacheco, Rita; Santos, Susana

Cancer is a generic term for a large group of diseases that are the second-leading cause of death worldwide, accounting for nearly 10 million deaths in 2020. Melanoma is a highly aggressive skin tumor with an increasing incidence and poor prognosis in the metastatic stage. Breast cancer still stands as one of the major cancer-associated deaths among women, and diagnosed cases are increasing year after year worldwide. Despite the recent therapeutic advances for this type of cancer, novel drugs and treatment strategies are still urgently needed. In this paper, the synthesis of 18 thiobenzanilide derivatives (17 of them new) is described, and their cytotoxic potential against melanoma cells (A375) and hormone-dependent breast cancer (MCF-7) cells is evaluated using the MTT assay. In the A375 cell line, most of the tested thiobenzanilides derivatives showed EC50 values in the order of mu M. Compound 17 was the most promising, with an EC50 (24 h) of 11.8 mu M. Compounds 8 and 9 are also interesting compounds that deserve to be further improved. The MCF-7 cell line, on the other hand, was seen to be less susceptible to these thiobenzanilides indicating that these compounds show different selectivity towards skin and breast cancer cells. Compound 15 showed the highest cytotoxic potential for MCF-7 cells, with an EC50 (24 h) of 43 mu M, a value within the range of the EC50 value determined for tamoxifen (30.0 mu M). ADME predictions confirm the potential of the best compounds. Overall, this work discloses a new set of thiobenzanilides that are worth being considered as new scaffolds for the further development of anticancer agents.

2023-02-16Journal article

Open access

Toxicidade e metabolismo de novas catinonas: a ameaça das drogas ilícitas emergentes

Publication . Ferreira, Inês Maria Ramos; Pacheco, Rita Isabel Dias; Gaspar, Helena Margarida Guerreiro Galla

As catinonas sintéticas, são β-ceto análogos das anfetaminas, e por isso, consideradas psicostimulantes. Estes compostos são sintetizados de forma a serem estruturalmente diferentes dos compostos ilegais, e por isso, aparecem no mercado como substâncias legais, representando uma alternativa de drogas de abuso, de fácil acesso no mercado. Este trabalho teve como objetivos efetuar o estudo da permeabilidade da barreira gastrointestinal de oito catinonas sintéticas: 3’-CMC, 4’-CMC, 3’-CEC, 4’-CEC,3’-CBC, 4’-CBC, 3’-Cl-DEC e 4’-Cl-DEC. Consequentemente, foi ainda necessário avaliar a sua toxicidade na linha celular Caco-2 e desenvolver um método de quantificação destas substâncias por HPLC-DAD. A metodologia de HPLC-DAD desenvolvida mostrou ser linear na gama de concentrações avaliadas (1 a 25 μg/mL). O estudo da permeabilidade para cada catinona, foi efetuado com o valor da concentração do IC50 (entre 1,80 e 6,10 mM), obtido para a citotoxicidade, a partir do método MTT. Esta avaliação permitiu identificar que as catinonas mais tóxicas nas Caco-2 são as 3’-CBC e 4’-CBC, cujos IC50 são 1,87 mM e 1,90 mM, respetivamente. A catinona com maior taxa de permeação é a 4’-CEC, cujo valor de Papp foi de 4,89x10-6 cm/s, indicando que possui permeabilidade moderada. O estudo na linha celular Caco-2 sugere que existe uma relação entre a estrutura das catinonas e a sua citotoxicidade, mostrando que um aumento na cadeia N-alquílica conduz a um aumento da sua toxicidade, contudo a posição do átomo de cloro parece não influenciar a toxicidade. Numa tentativa de perceber se as células normais têm um comportamento semelhante às células cancerígenas foi efetuado um estudo da citotoxicidade da 4’-CBC, por ser uma das mais tóxicas, em fibroblastos da derme humana, cujo valor do IC50 poderá ser, aproximadamente, 0,80 mM. De modo a tentar compreender o mecanismo de toxicidade na linha celular HepG-2 foi ainda realizado um estudo de metabolómica por espectrometria de massa de alta resolução (LC-HRMS) nestas células, com a 4’-CEC, por ter sido a que apresentou maior permeação. No modo positivo, verificou-se que os metabolitos extraídos das células controlo são diferentes dos metabolitos das células expostas à catinona, com variação de 81% e r2=0,79. Para as células controlo foram propostos metabolitos como espermidina e monofosfato de uridina. Nas células tratadas foram propostos a N1-acetilespermidina e oleamida, indicando que a catinona afeta negativamente as células. Apesar de se ter efetuada ainda a quantificação de proteínas extraídas das células da linha celular HepG2, expostas à catinona em comparação com as células controlo e uma SDS-PAGE, os resultados não foram conclusivos. Este trabalho contribuiu para o aumento do conhecimento do efeito tóxico de catinonas sintéticas que circulam no mercado.

2023Master thesis

Open access

Exploring the Hypocholesterolemic Potential of a Fucus vesiculosus Extract: Omic Insights into Molecular Mechanisms at the Intestinal Level

Publication . Rebeca, André; Pacheco, Rita; Santos, Hugo M.; Serralheiro, Maria Luisa

High blood cholesterol levels are a major risk factor for cardiovascular diseases. A purified aqueous extract of Fucus vesiculosus, rich in phlorotannins and peptides, has been described for its potential to inhibit cholesterol biosynthesis and intestinal absorption. In this work, the effect of this extract on intestinal cells' metabolites and proteins was analysed to gain a deeper understanding of its mode of action on lipids' metabolism, particularly concerning the absorption and transport of exogenous cholesterol. Caco-2 cells, differentiated into enterocytes, were exposed to the extract, and analysed by untargeted metabolomics and proteomics. The results of the metabolomic analysis showed statistically significant differences in glutathione content of cells exposed to the extract compared to control cells, along with an increased expression of fatty acid amides in exposed cells. A proteomic analysis showed an increased expression in cells exposed to the extract compared to control cells of FAB1 and NPC1, proteins known to be involved in lipid metabolism and transport. To the extent of our knowledge, this study is the first use of untargeted metabolomics and a proteomic analysis to investigate the effects of F. vesiculosus on differentiated Caco-2 cells, offering insights into the molecular mechanism of the extract’s compounds on intestinal cells.

2024-04-20Journal article

Open access