Untitled

Funder

Organizational Unit

Publications

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

Antioxidant and neuroprotective potential of the brown seaweed Bifurcaria bifurcata in an in vitro Parkinson’s Disease Model

Publication . Silva, Joana; Alves, Celso; Freitas, Rafaela; Martins, Alice; Pinteus, Susete; Ribeiro, Joana; Gaspar, Helena; Alfonso, Amparo; Pedrosa, Rui

Bifurcaria bifurcata is a marine brown seaweed mainly found on the Atlantic coast. Herein, we report the antioxidant and neuroprotective activities of seven fractions (F1–F7) obtained by normal phase chromatography from the B. bifurcata dichloromethane extract, as well as of its two major isolated diterpenes. Total phenolic content of fractions was determined by the Folin–Ciocalteu method, while antioxidant activity was evaluated by the DPPH, ORAC, and FRAP assays. Neuroprotective effects were evaluated in a neurotoxic model induced by 6-hydroxydopamine (6-OHDA) in a human neuroblastoma cell line (SH-SY5Y), while the mechanisms associated to neuroprotection were investigated by the determination of mitochondrial membrane potential, H2O2 production, Caspase-3 activity, and by observation of DNA fragmentation. Fractions F4 and F5 exhibited the best neuroprotective and antioxidant activities, respectively. F4 fraction prevented changes in mitochondrial potential, and induced a reduction of H2O2 levels production and an increase in cell viability, suggesting that it may contain multi-target compounds acting on different pathways. Hence, this fraction was subjected to purification steps, affording the known diterpenes eleganolone and eleganonal. Both compounds exhibited antioxidant potential, being interesting candidates for further neuroprotective studies.

2019Journal article

Open access

The marine invasive seaweeds Asparagopsis armata and Sargassum muticum as targets for greener antifouling solutions

Publication . Pinteus, Susete; Lemos, Marco F.L.; Alves, Celso; Silva, Joana; Pedrosa, Rui

Biofouling is a complex phenomenon that affects all maritime dependent industries. The accumulation of both micro and macro-organisms in immerged structures increases significantly the maintenance expenses, and thus the use of antifouling substances is inevitable. Although with recognized antifouling properties, the available antifouling coatings are known to induce negative impacts in aquatic ecosystems. Therefore, greener alternatives are urgently required. Living underwater, marine organisms are prone to biofouling and some have developed strategies to defend themselves against undesirable organisms, which include the production of bioactive substances. As a result, marine organisms are promising sources of natural antifouling substances. Within this framework, the marine invasive seaweeds Sargassummuticumand Asparagopsis armatawere addressed for antifouling compounds biodiscovery. Both seaweeds revealed antifouling properties against microfoulers, namely algicidal and anti-biofilm activities; however Asparagopsis armata stand out for its capacity to inhibit marine bacteria and microalgae growth, to decrease biofilm formation, and for acting as a neurotransmitter disruptor through the inhibition of acetylcholinesterase activity. By addressing invasive species, the problematic of the biological material supply for industrial purposes is surpassed while mitigating the negative impacts of invasive species through specimen's collection.

2021Journal article

Restricted access

Highlighting the biological potential of the brown seaweed Fucus spiralis for skin applications

Publication . Freitas, Rafaela; Martins, Alice; Silva, Joana; Alves, Celso; Pinteus, Susete; Alves, Joana; Teodoro, Fernando; Ribeiro, Helena Margarida; Gonçalves, Lídia; Petrovski, Zeljko; Branco, Luís; Pedrosa, Rui

Skin aging is a biological process influenced by intrinsic and extrinsic factors. The last ones, mainly exposure to UV radiation, increases reactive oxygen species (ROS) production leading to a loss of extracellular matrix, also enhanced by enzymatic degradation of matrix supporting molecules. Thus, and with the growing demand for eco-friendly skin products, natural compounds extracted from brown seaweeds revealed to be good candidates due to their broad range of bioactivities, especially as antioxidants. The aim of this study was to assess the dermo-cosmetic potential of di erent fractions obtained from the brown seaweed Fucus spiralis. For this purpose, in vitro antioxidant (Total Phenolic Content (TPC), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, Ferric Reducing Antioxidant Power (FRAP), Oxygen Radical Absorbance Capacity (ORAC)), anti-enzymatic (collagenase, elastase and hyaluronidase), antimicrobial, anti-inflammatory (NO production) and photoprotective (ROS production) capacities were evaluated. Although nearly all fractions evidenced antioxidant e ects, fraction F10 demonstrated the highest antioxidant ability (EC50 of 38.5 g/mL, DPPH assay), and exhibited a strong e ect as an inhibitor of collagenase (0.037 g/mL) and elastase (3.0 g/mL). Moreover, this fraction was also the most potent on reducing ROS production promoted by H2O2 (IC50 of 41.3 g/mL) and by UVB (IC50 of 31.3 g/mL). These bioactivities can be attributed to its high content of phlorotannins, as evaluated by LC-MS analysis, reinforcing the potential of F. spiralis for further dermatological applications.

2020Journal article

Open access