Browsing by Author "Pedrosa, Rui"
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- Adjunctive role of Calyptranthes tricona extract with probiotic Kluyveromyces marxianus on colorectal adenocarcinoma Caco-2 cellsPublication . Kich, Débora Mara; Bitencourt, Shanna; Faleiro, Dalana; Immich, Sheila Mariele; Marmitt, Diorge Jonatas; Baldasso, Tamara; Haute, Gabriela Viegas; Oliveira, Jarbas Rodrigues de; Laufer, Stefan; Pedrosa, Rui; Souza, Claucia Fernanda Volken de; Goettert, Márcia InêsThe composition of microbiota may influence the development of colorectal cancer (CRC). In addition, probiotics can decrease the chance of developing cancer or its progress. For that reason, it is encouraging to assess the influence of plant extracts as adjuvants of the health-promoting effects of probiotics. Thus, this study aimed to investigate the in vitro beneficial properties of Calyptranthes tricona leaf ethanol extract in association or not with the lactic yeast Kluyveromyces marxianus on colon adenocarcinoma Caco-2 cells. C. tricona extract inhibited the in vitro p38α MAPK activity and exhibited immunomodulation on isolated human lymphocytes. Further, the extract did not induce cytotoxicity towards K. marxianus or Caco-2 cells; leading to an increased yeast adhesion to cells in a dose-dependent manner. In conclusion, this preliminary study demonstrates that C. tricona extract has effects on enzyme inhibition and immune function. In addition, when associated with K. marxianus, C. tricona may possess beneficial properties for application as enhancer of probiotic’s protective role on CRC cells. However, further studies are necessary in order to elucidate the mechanisms involved.
- Algae from Portuguese Coast Presented High Cytotoxicity and Antiproliferative Effects on an In vitro Model of Human Colorectal CancerPublication . Alves, Celso; Pinteus, Susete; Rodrigues, Ana; Horta, André; Pedrosa, RuiBackground: The marine environment has shown to be an interesting source of new antitumor agents, representing an important tool in cancer research. Objective: The aim of this study was to evaluate the antitumor activities of 12 algae from Peniche coast (Portugal) on an in vitro model of human colorectal cancer (Caco‑2 cells). Materials and Methods: The antitumor potential was accessed by evaluating Caco‑2 cell’s viability and proliferation through the 3‑[4, 5‑dimethylthiazol‑2‑yl]‑2, 5‑diphenyl tetrazolium bromide and calcein‑AM methods. Results: The dichloromethane extracts of Asparagopsis armata and Sphaerococcus coronopifolius induced the highest decrease on cell’s viability (1 mg/mL; 24 h), 98.96% ± 0.39% and 98.08% ± 0.89%, respectively, followed by the methanolic extracts of S. coronopifolius (96.47% ± 1.26%) and A. armata (92.68% ± 1.17%). Regarding cell proliferation, the highest decrease of Caco‑2 cell’s proliferation (1 mg/mL; 24 h) was induced by the dichloromethane extract of A. armata (100% ± 0.48%), S. coronopifolius (99.04 ± 0.51%), and Plocamium cartilagineum (95.05% ± 1.19%). The highest potency was shown by the dichloromethane extract of S. coronopifolius in both, cytotoxicity and antiproliferative tests, with an IC50 of 21.3 and 36.5 µg/mL, respectively. Conclusion: The extracts of A. armata and S. coronopifolius are promising sources of new bioactive molecules with application in cancer therapeutics.
- An Insight into Sargassum muticum Cytoprotective Mechanisms against Oxidative Stress on a Human Cell In Vitro ModelPublication . Pinteus, Susete; Lemos, Marco; Silva, Joana; Alves, Celso; Neugebauer, Agnieszka; Freitas, Rafaela; Duarte, Adriana; Pedrosa, RuiSargassum muticum is a brown seaweed with strong potential to be used as a functional food ingredient, mainly due to its antioxidant properties. It is widely used in traditional oriental medicine for the treatment of numerous diseases. Nevertheless, few studies have been conducted to add scientific evidence on its effects as well as on the mechanisms of action involved. In this work, the human cell line MCF-7 was used as an in vitro cellular model to evaluate the capability of Sargassum muticum enriched fractions to protect cells on an oxidative stress condition. The concentration of the bioactive compounds was obtained by vacuum liquid chromatography applied on methanol (M) and 1:1 methanol:dichloromethane (MD) crude extracts, resulting in seven enriched fractions from the M extraction (MF2-MF8), and eight fractions from the MD extraction (MDF1-MDF8). All fractions were tested for cytotoxic properties on MCF-7 cells and the nontoxic ones were tested for their capacity to blunt the damaging effects of hydrogen peroxide-induced oxidative stress. The nontoxic effects were also confirmed in 3T3 fibroblast cells as a nontumor cell line. The antioxidant potential of each fraction, as well as changes in the cell's real-time hydrogen peroxide production, in the mitochondrial membrane potential, and in Caspase-9 activity were evaluated. The results suggest that the protective effects evidenced by S. muticum can be related with the inhibition of hydrogen peroxide production and the inhibition of Caspase-9 activity.
- Antifungal and Antioxidant Properties of Chitosan Polymers Obtained from Nontraditional Polybius henslowii SourcesPublication . Avelelas, Francisco; Horta, André; Pinto, Luís F.V.; Marques, Sónia Cotrim; Nunes, Paulo; Pedrosa, Rui; Leandro, Sérgio MiguelChitin was extracted from Polybius henslowii, a swimming crab, captured in large quantities throughout the Portuguese coast by purse seine vessels as bycatch. After standard chitin extraction procedures, water-soluble chitosan products were obtained via two di erent methods: (1) N-acetylation with the addition of acetic anhydride and (2) a reaction with hydrogen peroxide. The chemical structure and molecular weight of chitosan derivatives, water-soluble chitosan (WSC) and chitooligosaccharides (COS), were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and gel permeation chromatography (GPC).Antioxidant and metal chelation activities were evaluated, and the growth inhibition capacity was tested on four phytopatogens. The chitooligosaccharides from pereopods (pCOS) and shell body parts (sCOS) inhibited all fungal species tested, particularly Cryphonectria parasitica with 84.7% and 85.5%, respectively. Both radical scavenging and antifungal activities proved to be dose-dependent. Chitooligosaccharides with a low molecular weight (2.7, 7.4, and 10.4 Kg mol1) showed the highest activity among all properties tested. These results suggested that chitosan derivatives from P. henslowii raw material could potentially be used against phytopathogens or as ingredient in cosmetics and other products related to oxidative stress.
- Antimicrobial activities of highly bioavailable organic salts and ionic liquids from fluoroquinolonesPublication . Santos, Miguel M.; Alves, Celso; Silva, Joana; Florindo, Catarina; Petrovski, Zeljko; Marrucho, Isabel M.; Pedrosa, Rui; Branco, Luís C.As the development of novel antibiotics has been at a halt for several decades, chemically enhancing existing drugs is a very promising approach to drug development. Herein, we report the preparation of twelve organic salts and ionic liquids (OSILs) from ciprofloxacin and norfloxacin as anions with enhanced antimicrobial activity. Each one of the fluoroquinolones (FQs) was combined with six di erent organic hydroxide cations in 93–100% yield through a bu er-assisted neutralization methodology. Six of those were isomorphous salts while the remaining six were ionic liquids, with four of them being room temperature ionic liquids. The prepared compounds were not toxic to healthy cell lines and displayed between 47- and 1416-fold more solubility in water at 25 and 37 C than the original drugs, with the exception of the ones containing the cetylpyridinium cation. In general, the antimicrobial activity against Klebsiella pneumoniae was particularly enhanced for the ciprofloxacin-based OSILs, with up to ca. 20-fold decreases of the inhibitory concentrations in relation to the parent drug, while activity against Staphylococcus aureus and the commensal Bacillus subtilis strain was often reduced. Depending on the cation–drug combination, broad-spectrum or strain-specific antibiotic salts were achieved, potentially leading to the future development of highly bioavailable and safe antimicrobial ionic formulations.
- Antimicrobial and antileukemic effects: in vitro activity of Calyptranthes grandifolia aqueous leaf extractPublication . Majolo, Fernanda; Bitencourt, Shanna; Monteiro, Bruna Wissmann; Haute, Gabriela Viegas; Alves, Celso; Silva, Joana; Pinteus, Susete; Santos, Roberto Christ Vianna; Torquato, Heron Fernandes Vieira; Paredes-Gamero, Edgar Julian; Oliveira, Jarbas Rodrigues; Souza, Claucia Fernanda Volken De; Pedrosa, Rui; Laufer, Stefan; Goettert, Márcia InêsNatural products are still a promising source of bioactive molecules. Food and Drug Administration data showed that approximately 49% of the approved molecules originate naturally or chemicallyresemble these substances, of which more than 70% are being used in anticancer therapy. It is noteworthy that at present there are no scientific studies to prove the effectiveness and safety of a number of plants used in folk medicine such as in the case of Calyptranthes grandifolia O. Berg (Myrtaceae) originally from South America. The aim of the present study was to determine the biological potential and toxicological effects of the aqueous leaf extract of C. grandifolia. The main detected phytoconstituents were condensed tannins and flavonoids and a high quantity of polyphenols. Regarding the antimicrobial potential, the extract exerted inhibitory activity against Pseudomonas aeruginosa. The results also revealed the extract induced DNA damage in a concentration-dependent manner in RAW 264.7 cells. In addition, C. grandifolia produced cytotoxicity in leukemia cell lines (HL60 and Kasumi-1) without affecting isolated human lymphocytes but significantly inhibited JAK3 and p38α enzyme activity. Taken together, these findings add important information on the biological and toxicological effects of C. grandifolia, indicating that aqueous extract may be a source of natural antimicrobial and antileukemic constituents.
- Antioxidant and antimicrobial potential of six Fucoids from the Mediterranean Sea and the Atlantic OceanPublication . De La Fuente, Gina; Pinteus, Susete; Silva, Joana; Alves, Celso; Pedrosa, RuiBACKGROUD: In recent years, research on the bioactive properties of macroalgae has increased, due to the great interest in exploring new products that can contribute to improve human health and wellbeing. In the present study, the antioxidant and antimicrobial potential of six different brown algae of the Fucales order were evaluated, namely Ericaria selaginoides, Ericaria amentacea, Gongolaria baccata, Gongolaria usneoides, Cystoseira compressa and Sargassum vulgare (collected along the Mediterranean and Atlantic coasts). The antioxidant capacity was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, the oxygen radical absorbent capacity (ORAC) and the ferric reducing antioxidant power (FRAP) and were related to the total phenolic content (TPC). The antimicrobial activity was evaluated measuring the growth inhibition of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. RESULTS: The highest antioxidant capacity was obtained for Ericaria selaginoides revealing the highest capacity to scavenge DPPH radical [half maximal effective concentration (EC50) = 27.02 ug mL−1], highest FRAP (1761.19 umol FeSO4 equivalents g−1 extract), high ORAC (138.92 umol TE g−1 extract), alongside to its high TPC (121.5 GAE g−1 extract). This species also reported the highest antimicrobial capacity against Staphylococcus aureus [half maximal inhibitory concentration (IC50) = 268 ug mL−1]. CONCLUSIONS: Among all studied seaweed, Ericaria selaginoides reveals the highest antioxidant and antimicrobial activities, and thus should be explored as a natural food additive and/or functional ingredient.
- Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteriaPublication . Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, RuiSurface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.
- Antioxidant and antitumor potential of wild and IMTA-cultivated Osmundea pinnatifidaPublication . Silva, J. Paulo; Alves, Celso; Pinteus, Susete; Silva, Joana; Valado, Ana; Pedrosa, Rui; Pereira, LeonelOsmundea pinnatifida is a red edible seaweed known as pepper dulse. O. pinnatifida was cultivated in the farm of ALGAplus (Ílhavo, Portugal). This farm is integrated with a seabream and seabass commercial aquaculture and uses the nutrient-enriched water resultant from the fish production as its cultivation medium in the integrated multi-trophic aquaculture (IMTA) manner. Wild and IMTA-cultivated samples of O. pinnatifida were screened for antioxidant and antitumor activities. The antioxidant capacity of solvent extracts from wild and IMTA cultivated samples was assessed in two methods (2,2-diphenyl- 1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC)), and their total phenolic contents (TPC) were estimated. Antitumor activity was evaluated in three different tumor cell lines (HepG- 2, MCF-7, and SH-SY5Y) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the solvents used for extraction, dichloromethane was the most effective to extract phenolic compounds and presented higher ORAC. A significant correlation was found between TPC and ORAC, which was also sustained by the principal components analysis (PCA). Dichloromethane extracts induced a cytostatic effect on MCF-7 cells and showed weak cytotoxicity to SH-SY5Y cells and weak impact on cell proliferation. Overall, there were no statistically signifi cant diff erences in the biological activities shown by the wild and IMTA-cultivated samples. Hence, O. pinnatifida can be obtained in an economical and environmentally sustainable way through IMTA, maintaining bioactive properties in a high potential for further nutraceutical purposes.
- Antioxidant and Cytoprotective Activities of Fucus spiralis Seaweed on a Human Cell in Vitro ModelPublication . Pinteus, Susete; Silva, Joana; Alves, Celso; Horta, André Gustavo Cavadas da; Thomas, Olivier P.; Pedrosa, RuiAntioxidants play an important role as Reactive Oxygen Species (ROS) chelating agents and, therefore, the screening for potent antioxidants from natural sources as potential protective agents is of great relevance. The main aim of this study was to obtain antioxidant-enriched fractions from the common seaweed Fucus spiralis and evaluate their activity and efficiency in protecting human cells (MCF-7 cells) on an oxidative stress condition induced by H₂O₂. Five fractions, F1-F5, were obtained by reversed-phase vacuum liquid chromatography. F3, F4 and F5 revealed the highest phlorotannin content, also showing the strongest antioxidant effects. The cell death induced by H₂O₂ was reduced by all fractions following the potency order F4 > F2 > F3 > F5 > F1. Only fraction F4 completely inhibited the H₂O₂ effect. To understand the possible mechanisms of action of these fractions, the cellular production of H₂O₂, the mitochondrial membrane potential and the caspase 9 activity were studied. Fractions F3 and F4 presented the highest reduction on H₂O₂ cell production. All fractions decreased both caspase-9 activity and cell membrane depolarization (except F1). Taken all together, the edible F. spiralis reveal that they provide protection against oxidative stress induced by H₂O₂ on the human MCF-7 cellular model, probably acting as upstream blockers of apoptosis.