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- 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.
- The biotechnological and seafood potential of Stichopus regalisPublication . Santos, Rita; Dias, Simaura; Pinteus, Susete; Silva, Joana; Alves, Celso; Tecelão, Carla; Pombo, Ana; Pedrosa, RuiSea cucumbers are highly used not only for the production of the bêche-de-mer, but also recent studies have been showing the high potential of these marine invertebrates on the pharmaceutical industry, as they are rich in bioactive compounds with important functions. Stichopus regalis extracts (1 mg∙mL−1) were used in antioxidant, antimicrobial and antitumor assays. The lipid profile was also evaluated. No significant antioxidant activity was detected in both methanolic and dichloromethane extracts. The methanolic fraction showed the highest antimicrobial potential against Candida albicans with an IC50 of 475.4 μg∙mL−1. In the antitumor assays, the dichloromethane fraction showed a high potential for both cell lines, as revealed by the MTT method. The total fat content was 3.63% ± 0.11% and the fatty acid profile revealed the highest amount in C16:0 (9.43% ± 0.77%), C18:0 (12.43% ± 0.83%), C18:1 ω7 (5.63% ± 0.33%), EPA (12.49% ± 0.15%), DHA (7.35% ± 0.02%), ARA (19.29% ± 0.14%) and a ω3/ω6 ratio of 1.078. These findings led us to suggest the potential use of S. regalis as a new source of bioactive compounds with pharmacological potential and its nutritional benefits for human health.
- 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.
- Sulfated polysaccharides from macroalgae: A simple roadmap for chemical characterizationPublication . Martins, Alice; Alves, Celso; Silva, Joana; Pinteus, Susete; Gaspar, Helena; Pedrosa, RuiThe marine environment presents itself as a treasure chest, full of a vast diversity of organisms yet to be explored. Among these organisms, macroalgae stand out as a major source of natural products due to their nature as primary producers and relevance in the sustainability of marine ecosystems. Sulfated polysaccharides (SPs) are a group of polymers biosynthesized by macroalgae, making up part of their cell wall composition. Such compounds are characterized by the presence of sulfate groups and a great structural diversity among the different classes of macroalgae, providing interesting biotechnological and therapeutical applications. However, due to the high complexity of these macromolecules, their chemical characterization is a huge challenge, driving the use of complementary physicochemical techniques to achieve an accurate structural elucidation. This review compiles the reports (2016–2021) of state-of-the-art methodologies used in the chemical characterization of macroalgae SPs aiming to provide, in a simple way, a key tool for researchers focused on the structural elucidation of these important marine macromolecules.
- Gelidiales are not just agar: Revealing the antimicrobial potential of Gelidium corneum for skin disordersPublication . Matias, Margarida; Pinteus, Susete; Martins, Alice; Silva, Joana; Alves, Celso; Mouga, Teresa; Gaspar, Helena; Pedrosa, RuiIn recent decades, seaweeds have proven to be an excellent source of bioactive molecules. Presently, the seaweed Gelidium corneum is harvested in a small area of the Portuguese coast exclusively for agar extraction. The aim of this work was to fully disclosure Gelidium corneum as a sustainable source of antimicrobial ingredients for new dermatological formulations, highlighting its potential to be explored in a circular economy context. For this purpose, after a green sequential extraction, these seaweed fractions (F1–F5) were chemically characterized (1H NMR) and evaluated for their antimicrobial potential against taphylococcus aureus, Staphylococcus epidermidis and Cutibacterium acnes. The most active fractions were also evaluated for their effects on membrane potential, membrane integrity and DNA damage. Fractions F2 and F3 displayed the best results, with IC50 values of 16.1 (7.27–23.02) g/mL and 51.04 (43.36–59.74) g/mL against C. acnes, respectively, and 53.29 (48.75–57.91) g/mL and 102.80 (87.15–122.30) g/mL against S. epidermidis, respectively. The antimicrobial effects of both fractions seem to be related to membrane hyperpolarization and DNA damage. This dual mechanism of action may provide therapeutic advantages for the treatment of skin dysbiosis-related diseases.
- 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.
- Mitigating the negative impacts of marine invasive species – Sargassum muticum - a key seaweed for skincare products developmentPublication . Susano, Patrícia; Silva, Joana; Alves, Celso; Martins, Alice; Pinteus, Susete; Gaspar, Helena; Goettert, Márcia Inês; Pedrosa, RuiSargassum muticum is a highly invasive species, threatening marine biodiversity worldwide. One strategy to reduce marine invaders’ impacts is to promote their use as valuable biomass for new products development. On the other hand, there is a rising conscience of natural compounds importance as health promoters. The present work was designed to sustainably use the marine invasive seaweed S. muticum collected off the Portuguese shore for novel skincare products. The antioxidant, anti-enzymatic (collagenase, elastase, hyaluronidase, tyrosinase), antimicrobial (Staphylococcus epidermidis, Cutibacterium acnes, Malassezia furfur), photoprotective, and antiinflammatory properties of five fractions (F1–F5) obtained by a sequential extraction of S. muticum were evaluated. The diethyl ether fraction (F2) demonstrated the most promising results, with the highest antioxidant and photoprotective capacity, reducing reactive oxygen species (ROS) production promoted by UVA and UVB radiation in 3T3 cells. On the other hand, the ethyl acetate fraction (F3) exhibited the highest anti-enzymatic capacity, inhibiting the activities of collagenase, hyaluronidase and tyrosinase (IC50 of 97.5, 23.7 and 72.3 μg/mL, respectively). Moreover, fractions from S. muticum showed anti-inflammatory potential by reducing tumor necrosis factor – α and interleukin-6 release. A chemical screening by 1H NMR of S. muticum fractions evidenced signals that can be attributed to the presence of different chemical classes, including lipids, pigments, amino acids, polyphenols, and sugars, being related to the observed multitarget properties. This work highlights a strategic valorisation of S. muticum as a source of treasured ingredients for skincare applications.
- Lymphocyte genotoxicity and protective effect of Calyptranthes tricona (Myrtaceae) against H 2 O 2-induced cell death in MCF-7 cellsPublication . Kich, Débora Mara; Bitencourt, Shanna; Caye, Bruna; Faleiro, Dalana; Alves, Celso; Silva, Joana; Pinteus, Susete; Mergener, Michelle; Majolo, Fernanda; Boligon, Aline Augusti; Santos, Roberto Christ Vianna; Pedrosa, Rui; Souza, Claucia Fernanda Volken de; Goettert, Márcia InêsCalyptranthes tricona is a species (Myrtaceae) native to South Brazil. Plants belonging to this family are folkloric used for analgesia, inflammation, and infectious diseases. However, little is known about the toxic potential of C. tricona. The present study aimed to evaluate the antioxidant activity of C. tricona ethanol and hexane leaf extracts, as well as verify their effect on human lymphocytes and MCF-7 cells. The extracts were subjected to preliminary phytochemical screening, antioxidant activity using DPPH and ORAC methods. Genotoxic and mutagenic effects in cultured human lymphocytes were assessed using the comet assay and the micronucleus assay, respectively. In addition, cell viability by MTT assay and fluorometric analysis of mitochondrial potential and caspases-9 activity were performed in order to verify the possible effects of both extracts on H2O2-induced cell death of MCF-7 cells. Our findings revealed that the phenol content and the antioxidant activity were only present in the ethanol extract. Also, the phytochemical screening presented steroids, triterpenoids, condensed tannins, and flavones as the main compounds. However, both extracts were capable of inducing concentration-dependent DNA damage in human lymphocytes. When treating MCF-7 cells with the extracts, both of them inhibited MCF-7 cell death in response to oxidative stress through a decrease of mitochondrial depolarization and caspases-9 activity. Thus, our results need to be considered in future in vitro and in vivo studies of C. tricona effects. In the meanwhile, we recommend caution in the acute/chronic use of this homemade preparation for medicinal purpose.
- From marine origin to therapeutics: the antitumor potential of marine algae-derived compoundsPublication . Alves, Celso; Silva, Joana; Pinteus, Susete; Gaspar, Helena; Alpoim, Maria C.; Botana, Luís M.; Pedrosa, RuiMarine 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.
- Unravelling the anti-Inflammatory and antioxidant potential of the marine sponge Cliona celata from the Portuguese coastlinePublication . Gaspar, Helena; Silva, Joana; Alves, Celso; Martins, Alice; Teodoro, Fernando; Susano, Patrícia; Pinteus, Susete; Pedrosa, Rui; Alves, JoanaInflammation is a double-edged sword, as it can have both protective effects and harmful consequences, which, combined with oxidative stress (OS), can lead to the development of deathly chronic inflammatory conditions. Over the years, research has evidenced the potential of marine sponges as a source of effective anti-inflammatory therapeutic agents. Within this framework, the purpose of this study was to evaluate the antioxidant and the anti-inflammatory potential of the marine sponge Cliona celata. For this purpose, their organic extracts (C1–C5) and fractions were evaluated concerning their radical scavenging activity through 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and anti-inflammatory activity through a (lipopolysaccharides (LPS)-induced inflammation on RAW 264.7 cells) model. Compounds present in the two most active fractions (F5 and F13) of C4 were tentatively identified by gas chromatography coupled to mass spectrometry (GC-MS). Even though samples displayed low antioxidant activity, they presented a high anti-inflammatory capacity in the studied cellular inflammatory model when compared to the anti-inflammatory standard, dexamethasone. GC-MS analysis led to the identification of n-hexadecanoic acid, cis-9-hexadecenal, and 13-octadecenal in fraction F5, while two major compounds, octadecanoic acid and cholesterol, were identified in fraction F13. The developed studies demonstrated the high anti-inflammatory activity of the marine sponge C. celata extracts and fractions, highlighting its potential for further therapeutic applications.