Escola Superior de Turismo e Tecnologia do Mar
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Browsing Escola Superior de Turismo e Tecnologia do Mar by Field of Science and Technology (FOS) "Ciências Médicas::Ciências da Saúde"
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- Anti-Hepatocellular Carcinoma (HepG2) Activities of Monoterpene Hydroxy Lactones Isolated from the Marine Microalga Tisochrysis LuteaPublication . Gangadhar, Katkam N.; Rodrigues, Maria João; Pereira, Hugo; Gaspar, Helena; Malcata, F. Xavier; Barreira, Luísa; Varela, JoãoTisochrysis lutea is a marine haptophyte rich in omega-3 polyunsaturated fatty acids (e.g., docosahexaenoic acid (DHA)) and carotenoids (e.g., fucoxanthin). Because of the nutraceutical applications of these compounds, this microalga is being used in aquaculture to feed oyster and shrimp larvae. In our earlier report, T. lutea organic crude extracts exhibited in vitro cytotoxic activity against human hepatocarcinoma (HepG2) cells. However, so far, the compound(s) accountable for the observed bioactivity have not been identified. Therefore, the aim of this study was to isolate and identify the chemical component(s) responsible for the bioactivity observed. Bioassay-guided fractionation through a combination of silica-gel column chromatography, followed by preparative thin layer chromatography (PTLC), led to the isolation of two diastereomers of a monoterpenoid lactone, namely, loliolide (1) and epi-loliolide (2), isolated for the first time in this species. The structural elucidation of both compounds was carried out by GC-MS and 1D (1 H and13 C APT) and 2D (COSY, HMBC, HSQC-ed, and NOESY) NMR analysis. Both compounds significantly reduced the viability of HepG2 cells and were considerably less toxic towards a non-tumoral murine stromal (S17) cell line, although epi-loliolide was found to be more active than loliolide. © 2020 by the authors.
- Asparagopsis armata and Sphaerococcus coronopifolius as a natural source of antimicrobial compoundsPublication . Pinteus, Susete; Alves, Celso; Monteiro, Hugo; Ernesto Araújo; Horta, André; Pedrosa, RuiMethanol, n-hexane and dichloromethane extracts of twelve marine macro-algae (Rhodophyta, Chlorophyta and Heterokontophyta divisions) from Peniche coast (Portugal) were evaluated for their antibacterial and antifungal activity. The antibacterial activity was evaluated by disc diffusion method against Bacillus subtilis (gram positive bacteria) and Escherichia coli (gram negative bacteria). Saccharomyces cerevisiae was used as a model for the antifungal activity by evaluating the growth inhibitory activity of the extracts. The high antibacterial activity was obtained by the Asparagopsis armata methanolic extract (10 mm–0.1 mg/disc), followed by the Sphaerococcus coronopifoliusn-hexane extract (8 mm–0.1 mg/disc), and the Asparagopsis armata dichloromethane extract (12 mm–0.3 mg/disc) against Bacillus subtilis. There were no positive results against Escherichia coli. Sphaerococcus coronopifolius revealed high antifungal potential for n-hexane (IC50 = 40.2 µg/ml), dichloromethane (IC50 = 78.9 µg/ml) and methanolic (IC50 = 55.18 µg/ml) extracts against Saccharomyces cerevisiae growth. The antifungal potency of the Sphaerococcus coronopifolius extracts was similar with the standard amphotericin B. Asparagopsis armata and Sphaerococcus coronopifolius reveal to be interesting sources of natural compounds with antimicrobial properties. © 2015, Springer Science+Business Media Dordrecht.
- Characterization of antiproliferative potential and biological targets of a copper compound containing 4′-phenyl terpyridinePublication . Mendo, Ana Soraia; Figueiredo, Sara; Roma-Rodrigues, Catarina; Videira, Paula A.; Ma, Zhen; Diniz, Mário; Larguinho, Miguel; Costa, Pedro M.; Lima, João C.; Pombeiro, Armando J. L.; Baptista, Pedro V.; Fernandes, Alexandra R.Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4′-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.
- Detection of QnrB54 and Its Novel Genetic Context in Citrobacter freundii Isolated from a Clinical CasePublication . Campos, Maria Jorge; Palomo, Gonzalo; Hormeño, Lorena; Rodrigues, Américo; Sánchez-Benito, Rosario; Píriz, Segundo; Quesada, AlbertoLETTER Quinolone resistance in Enterobacteriaceae is mediated by mutations in the quinolone resistance-determining regions (QRDR) of topoisomerase genes and/or by plasmid-mediated quinolone resistance determinants (PMQR) such as the qnr genes encoding pentapeptide repeat proteins (1). The qnrB family is represented by 80 different alleles (http://www.lahey.org/qnrStudies/); most of them originated from Citrobacter strains and spread to other Enterobacteriaceae species (2). This work describes the identification of a new allele of the quinolone resistance protein QnrB, QnrB54, in a human clinical isolate of Citrobacter freundii detected in Spain.
- Evaluating the Potential of the Defatted By-Product of Aurantiochytrium sp. Industrial Cultivation as a Functional FoodPublication . Reboleira, João; Félix, Rafael; Félix, Carina; Melo, Marcelo M. R. de; Silva, Carlos M.; Saraiva, Jorge A.; Bandarra, Narcisa M.; Teixeira, Bárbara; Mendes, Rogério; Paulo, Maria C.; Coutinho, Joana; Lemos, Marco F. L.While Aurantiochytrium sp. is an increasingly popular source of polyunsaturated fatty acids (PUFAs), its extraction generates high amounts of waste, including the spent, defatted residue. The composition and bioactivities of this by-product could prove to be a major part of the sustainable valorisation of this organism within the framework of a circular economy. In this study, the defatted biomass of commercial Aurantiochytrium sp. was nutritionally characterised, and its amino acid profile was detailed. Additionally, the antioxidant and prebiotic potentials of an enzymatically digested sample of defatted Aurantiochytrium sp. were evaluated under a set of miniaturised in vitro assays. The nutritional profile of the spent Aurantiochytrium biomass revealed a protein and dietary-fibre rich product, with values reaching 26.7% and 31.0% for each, respectively. It also held high concentrations of glutamic and aspartic acid, as well as a favourable lysine/arginine ratio of 3.73. The digested samples demonstrated significant Weissela cibaria and Bifidobacterium bifidum growth-enhancing potential. Residual ferric reducing antioxidant power (FRAP) activity was likely attributed to antioxidant amino acids or peptides. The study demonstrated that some of the nutritional and functional potential that reside in the defatted Aurantiochytrium sp. waste encourages additional studies and the development of food supplements employing this resource’s by-products under a biorefinery framework.
- Ridolfia segetum (L.) Moris (Apiaceae) from Portugal: A source of safe antioxidant and anti-inflammatory essential oilPublication . Cabral, C.; Poças Almeida, Juliana; Gonçalves, M.J.; Cavaleiro, C.; Cruz, M.T.; Salgueiro, L.Ridolfia segetum (L.) Moris essential oil was obtained by hydrodistillation and analysed by GC and GC-MS. The antioxidant properties were evaluated through the TBARS assay, and the in vitro anti-inflammatory activity was assessed through inhibition of NO production triggered by the Toll-like receptor 4 (TLR4) agonist, lipopolysaccharide (LPS), in mouse macrophages. Assessment of cell viability was made through a colorimetric assay using MTT on macrophages, keratinocytes, and hepatocytes. The main compounds are α-phellandrene (53.0-63.3%), terpinolene (11.9-8.6%), ß-phellandrene (5.5-6.0%), and dillapiol (1.9-8.0%). The oil demonstrated high antioxidant capacity in the concentrations tested (0.05-0.20. μL/mL) and significantly inhibited NO production without cytotoxicity in concentrations up to 1.25. μL/mL. The plants showed a high essential oil yield, which confers an industrial potential interest. Also, the high content of α-phellandrene (53.0-63.3%) makes it an important natural source of this compound. These results provide evidence of the therapeutic effects of this oil, and suggest that the anti-inflammatory activity in doses without cytotoxicity on mammalian cells, combined with its antioxidant potential and pleasant smell, could be of great value in the development of new phytopharmaceuticals.