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Identification of Asparagopsis armata‐associated bacteria and characterization of their bioactive potential

Publication . Alves, Celso; Pinteus, Susete; Lopes, Cláudia; Fino, Nádia; Silva, Joana; Ribeiro, Joana; Rodrigues, Daniel; Francisco, João; Rodrigues, Américo; Pedrosa, Rui; Horta, André

Macroalgae‐associated bacteria have already proved to be an interesting source of compounds with therapeutic potential. Accordingly, the main aim of this study was to characterize Asparagopsis armata‐associated bacteria community and evaluate their capacity to produce substances with antitumor and antimicrobial potential. Bacteria were selected according to their phenotype and isolated by the streak plate technique. The identification was carried out by the RNA ribosomal 16s gene amplification through PCR techniques. The antimicrobial activities were evaluated against seven microorganisms (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae, Candida albicans) by following their growth through spectrophotometric readings. Antitumor activities were evaluated in vitro on human cell lines derived from hepatocellular (HepG‐2) and breast carcinoma (MCF‐7) using the MTT method. The present work identified a total of 21 bacteria belonging to the genus Vibrio, Staphylococcus, Shewanella, Alteromonadaceae, Bacillus, Cobetia, and Photobacterium, with Vibrio being the most abundant (42.86%). The extract of Shewanella sp. ASP 26 bacterial strain induced the highest antimicrobial activity, namely against Bacillus subtilis and Staphylococcus aureus with an IC50 of 151.1 and 346.8 μg/mL, respectively. These bacteria (Shewanella sp.) were also the ones with highest antitumor potential, demonstrating antiproliferative activity on HepG‐2 cells. Asparagopsis armata‐associated bacteria revealed to be a potential source of compounds with antitumor and antibacterial activity.

2019Journal article

Open access

An Insight into Sargassum muticum Cytoprotective Mechanisms against Oxidative Stress on a Human Cell In Vitro Model

Publication . Pinteus, Susete; Lemos, Marco; Silva, Joana; Alves, Celso; Neugebauer, Agnieszka; Freitas, Rafaela; Duarte, Adriana; Pedrosa, Rui

Sargassum 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.

2017Journal article

Open access

Antioxidant and Cytoprotective Activities of Fucus spiralis Seaweed on a Human Cell in Vitro Model

Publication . Pinteus, Susete; Silva, Joana; Alves, Celso; Horta, André Gustavo Cavadas da; Thomas, Olivier P.; Pedrosa, Rui

Antioxidants 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.

2017Journal article

Open access

From marine origin to therapeutics: the antitumor potential of marine algae-derived compounds

Publication . Alves, Celso; Silva, Joana; Pinteus, Susete; Gaspar, Helena; Alpoim, Maria C.; Botana, Luís M.; Pedrosa, Rui

Marine environment has demonstrated to be an interesting source of compounds with uncommon and unique chemical features on which themolecularmodeling and chemical synthesis of new drugs can be based with greater efficacy and specificity for the therapeutics. Cancer is a growing public health threat, and despite the advances in biomedical research and technology, there is an urgent need for the development of new anticancer drugs. In this field, it is estimated that more than 60% of commercially available anticancer drugs are natural biomimetic inspired. Among the marine organisms, algae have revealed to be one of the major sources of new compounds of marine origin, including those exhibiting antitumor and cytotoxic potential. These compounds demonstrated ability to mediate specific inhibitory activities on a number of key cellular processes, including apoptosis pathways, angiogenesis, migration and invasion, in both in vitro and in vivo models, revealing their potential to be used as anticancer drugs. This review will focus on the bioactive molecules from algae with antitumor potential, from their origin to their potential uses, with special emphasis to the alga Sphaerococcus coronopifolius as a producer of cytotoxic compounds.

2018Journal article

Open access

Marine invasive macroalgae: Turning a real threat into a major opportunity - the biotechnological potential of Sargassum muticum and Asparagopsis armata

Publication . Pinteus, Susete; Lemos, Marco F.L.; Alves, Celso; Neugebauer, Agnieszka; Silva, Joana; Thomas, Olivier P.; Botana, Luis M.; Gaspar, Helena; Pedrosa, Rui

Marine invasive species are widely recognized as one of the worst threats to marine ecosystems integrity, un-balancing native communities, which may lead to paramount ecological and economic impacts. Within invasiveseaweeds, Sargassum muticum and Asparagopsis armata are recognized as successful invaders in Europe andAmerica. Despite several attempts to control the spread of marine invaders, until now, all have proven to beelusive, and therefore, alternative strategies should be embraced.Worldwide, seaweeds have been increasingly explored due to their ability to produce bioactive compounds.However, one of the main problems associated with the production/extraction of these bioactive compounds fornew products development, is the source availability and the potential negative environmental consequences ofthis exploitation.Within this framework, the use of invasive species to obtain natural bioactive compounds presents us with atwo-folded opportunity - high availability of the biological material for the extraction of unique bioactivecompounds for new products development, and through specimen collection, mitigating negative eﬀects causedby alien species, contributing for ecosystem integrity and sustainability.Over the last decades, the brown seaweed S. muticum and the red A. armata have been studied all over theworld for their capacity to produce bioactive compounds, with main results pointing towards their high potentialas producers of antioxidant, antifouling, antimicrobial, and antitumor compounds.The present review summarizes the biotechnological potential of S. muticum and A. armata as producers ofbioactive compounds, while addressing the potential use of global threats as important blue growth pawns.

2018-08-08Journal article

Restricted access