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- 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.
- Antiulcerogenic potential of the ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna evaluated by in vitro and in vivo studiesPublication . Dörr, Juliana Andréa; Majolo, Fernanda; Bortoluzzi, Luísa; Vargas, Evelin Zen de; Silva, Joana; Pasini, Manoela; Stoll, Stefani Natali; Rosa, Rafael Lopes da; Figueira, Mariana Moreira; Fronza, Marcio; Beys-da-Silva, Walter O.; Martins, Alice; Gaspar, Helena; Pedrosa, Rui; Laufer, StefanGastrointestinal diseases, such as peptic ulcers, are caused by a damage in the gastric mucosa provoked by several factors. This stomach injury is regulated by many inflammatory mediators and is commonly treated with proton-pump inhibitors, histamine H2 receptor blockers and antacids. However, various medicinal plants have demonstrated positive effects on gastric ulcer treatment, including plants of the Ceiba genus. The aim of this study was to evaluate the antiulcer and anti-inflammatory activities of the stem bark ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna. We performed a preliminary quantification of phenolic compounds by high-performance liquid chromatography-diode array detection (HPLC-DAD), followed by the prospection of other chemical groups through nuclear magnetic resonance (NMR) spectroscopy. A set of in vitro assays was used to evaluate the extract potential regarding its antioxidant activity (DPPH: 19.83 +- 0.34 ug/mL; TPC: 307.20 +- 6.20 mg GAE/g of extract), effects on cell viability and on the release of TNF-α in whole human blood. Additionally, in vivo assays were performed to evaluate the leukocyte accumulation and total protein quantification in carrageenan-induced air pouch, as well as the antiulcerogenic effect of the extract on an ethanol-induced ulcer in rats. The extract contains flavonoids and phenolic compounds, as well as sugars and quinic acid derivatives exhibiting potent antioxidant activity and low toxicity. The extract reduced the release of TNF-α in human blood and inhibited the activity of p38α (1.66 ug/mL), JAK3 (5.25 ug/mL), and JNK3 (8.34 ug/mL). Moreover, it reduced the leukocyte recruitment on the pouch exudate and the formation of edema, reverting the effects caused by carrageenan. The extract presented a significant prevention of ulcer formation and a higher reduction than the reference drug, Omeprazole. Therefore, C. speciosa extract has demonstrated relevant therapeutic potential for the treatment of gastric diseases, deserving the continuation of further studies to unveil the mechanisms of action of plant bioactive ingredients.
- 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.
- 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.
- Marine endophytic fungi associated with Halopteris scoparia (Linnaeus) Sauvageau as producers of bioactive secondary metabolites with potential dermocosmetic applicationPublication . Calado, Maria da Luz; Silva, Joana; Alves, Celso; Susano, Patrícia; Santos, Débora; Alves, Joana; Martins, Alice; Gaspar, Helena; Pedrosa, Rui; Campos, Maria JorgeMarine fungi and, particularly, endophytic species have been recognised as one of the most prolific sources of structurally new and diverse bioactive secondary metabolites with multiple biotechnological applications. Despite the increasing number of bioprospecting studies, very few have already evaluated the cosmeceutical potential of marine fungal compounds. Thus, this study focused on a frequent seaweed in the Portuguese coast, Halopteris scoparia, to identify the endophytic marine fungi associated with this host, and assess their ability to biosynthesise secondary metabolites with antioxidative, enzymatic inhibitory (hyaluronidase, collagenase, elastase and tyrosinase), anti-inflammatory, photoprotective, and antimicrobial (Cutibacterium acnes, Staphylococcus epidermidis and Malassezia furfur) activities. The results revealed eight fungal taxa included in the Ascomycota, and in the most representative taxonomic classes in marine ecosystems (Eurotiomycetes, Sordariomycetes and Dothideomycetes). These fungi were reported for the first time in Portugal and in association with H. scoparia, as far as it is known. The screening analyses showed that most of these endophytic fungi were producers of compounds with relevant biological activities, though those biosynthesised by Penicillium sect. Exilicaulis and Aspergillus chevalieri proved to be the most promising ones for being further exploited by dermocosmetic industry. The chemical analysis of the crude extract from an isolate of A. chevalieri revealed the presence of two bioactive compounds, echinulin and neoechinulin A, which might explain the high antioxidant and UV photoprotective capacities exhibited by the extract. These noteworthy results emphasised the importance of screening the secondary metabolites produced by these marine endophytic fungal strains for other potential bioactivities, and the relevance of investing more efforts in understanding the ecology of halo/osmotolerant fungi.
- Antioxidant and neuroprotective potential of the brown seaweed Bifurcaria bifurcata in an in vitro Parkinson’s Disease ModelPublication . Silva, Joana; Alves, Celso; Freitas, Rafaela; Martins, Alice; Pinteus, Susete; Ribeiro, Joana; Gaspar, Helena; Alfonso, Amparo; Pedrosa, RuiBifurcaria 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.
- Valorisation of Sargassum muticum through the extraction of phenolic compounds using eutectic solvents and intensification techniquesPublication . Jesus, Bárbara C.; Sáenz de Miera, Blanca; Santiago, Rubén; Martins, Alice; Pedrosa, Rui; Gonzalez-Miquel, Maria; Marrucho, Isabel M.Seaweeds are naturally abundant and spread all over the globe. They have several biologically active secondary metabolites of great interest. In this work, Sargassum muticum was the algae employed as biomass and the aim was to extract phenolic compounds (PCs) using eutectic solvents (ESs). Several betaine-based, proline-based, and choline-based ESs were tested for the extraction of PCs. All extracts were evaluated according to the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (DPPH). Afterwards, the extracts were characterized using HPLC in terms of 9 target PCs (gallic acid, 3,4-dihydroxybenzoic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, salicylic acid, catechin and quercetin). Proline combined with propylene glycol (Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG) exhibited a higher yield according to HPLC results, followed by proline[thin space (1/6-em)]:[thin space (1/6-em)]1,2-butanediol (Pro[thin space (1/6-em)]:[thin space (1/6-em)]1,2-But) and choline[thin space (1/6-em)]:[thin space (1/6-em)]citric acid (ChCl[thin space (1/6-em)]:[thin space (1/6-em)]CA). Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG also presented high selectivity towards salicylic acid, while ChCl[thin space (1/6-em)]:[thin space (1/6-em)]CA towards gallic acid. Optimization studies of water content and temperature were performed for the three best ESs, the optimum conditions being 30% (v/v) water and 60 °C extraction temperature. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) were two intensification methods evaluated to enhance the extraction process, proving their ability to reduce the extraction time when compared with the conventional solid–liquid extraction (SLE) process. In particular, Pro[thin space (1/6-em)]:[thin space (1/6-em)]PPG-based MAE provided a significantly higher extraction yield in comparison with conventional extraction and with the other extraction solvents. In summary, the combination of ESs with intensification techniques was shown to be a valuable valorization strategy of a marine macroalgae waste, in particular Sargassum muticum.
- Risk assessment of trihalomethanes exposure by consumption of IV gamma products: Evidences from a Portuguese regional surveyPublication . Simões, Cátia; Mendes, Susana; Martins, Alice; Gil, Maria M.Due to the current demand for healthier food, the IV gamma products industry has grown over the years. Additionally, it is well known that chlorine is a disinfectant largely used in this industry. However, the risk assessment associated with the formation of carcinogenic by-products from this halogenated disinfection has not been widely studied. The aim of this study was to assess the trihalomethanes (THMs) exposure through the consumption of IV gamma products, more specifically, salad mixes, and potential health risk in Portuguese population using a deterministic method. The quantification of THMs in salad mixes from the most representative Portuguese brands was performed by gas chromatography coupled to mass spectrometry (GC–MS). The THMs exposures were estimated by combining the THMs concentration data with a ready-to-eat salad mix consumption survey (case study applied in the Lisboa e Vale do Tejo area; n = 271). The concentration of THMs in all samples was below the limit of quantification of the equipment (1 μg/L), and this limit was used for the evaluation of the exposure. It was found that it is very small for the consumption pattern of these products in the studied population categories, suggesting that there is no risk for consumers due to the halogenated disinfection process. The highest estimated daily exposure was 7,65X10−5 mg/ kg bw/ week, which corresponds to a person who consumes such products daily.
- New insights into the dermocosmetic potential of the red seaweed Gelidium corneumPublication . Matias, Margarida; Martins, Alice; Alves, Celso; Silva, Joana; Pinteus, Susete; Fitas, Manuel; Pinto, Pedro; Marto, Joana; Ribeiro, Helena; Murray, Patrick; Pedrosa, RuiThis work addresses the potential of the red seaweed Gelidium corneum as a source of bioactive ingredients for skin health and wellness in response to the growing awareness regarding the significance of sustainable strategies in developing new nature-based dermocosmetic products. Hydroalcoholic extracts from the dried biomass were subjected to sequential liquid–liquid partitions, affording five different fractions (F1–F5). Their cosmetic potential was assessed through a set of in vitro assays concerning their antioxidant, photoprotective, and healing properties. Additionally, their cytotoxicity in HaCaT cells and their capacity to induce inflammation in RAW 264.7 cells were also evaluated. As a proof-of-concept, O/W emulsions were prepared, and emulsion stability was assessed by optical microscopy, droplet size analysis, centrifugation tests, and rheology analysis. Furthermore, in vivo tests were conducted with the final formulation to assess its antioxidant capacity. At subtoxic concentrations, the most lipophilic fraction has provided photoprotection against UV light-induced photooxidation in HaCaT cells. This was conducted together with the aqueous fraction, which also displayed healing capacities. Regarding the physical and stability assays, the best performance was achieved with the formulation containing 1% aqueous extract, which exhibited water retention and antioxidant properties in the in vivo assay. In summary, Gelidium corneum displayed itself as a potential source of bioactive ingredients with multitarget properties for dermatological use.
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