Biosystems and Integrative Sciences Institute

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Gelidiales are not just agar: Revealing the antimicrobial potential of Gelidium corneum for skin disorders

Publication . Matias, Margarida; Pinteus, Susete; Martins, Alice; Silva, Joana; Alves, Celso; Mouga, Teresa; Gaspar, Helena; Pedrosa, Rui

In 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.

2021Journal article

Open access

Antiulcerogenic potential of the ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna evaluated by in vitro and in vivo studies

Publication . 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, Stefan

Gastrointestinal 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.

2022Journal article

Open access

Bromoditerpenes from the red seaweed Sphaerococcus coronopifolius as potential cytotoxic agents and proteasome inhibitors and related mechanisms of action

Publication . Alves, Celso; Silva, Joana; Pintéus, Susete; Guedes, Romina A.; Guedes, Rita C.; Alvariño, Rebeca; Freitas, Rafaela; Goettert, Márcia I.; Gaspar, Helena; Alfonso, Amparo; Alpoím, Maria C.; Botana, Luis M.; Pedrosa, Rui

Seaweeds are a great source of compounds with cytotoxic properties with the potential to be used as anticancer agents. This study evaluated the cytotoxic and proteasome inhibitory activities of 12R-hydroxy-bromosphaerol, 12S-hydroxy-bromosphaerol, and bromosphaerol isolated from Sphaerococcus coronopifolius. The cytotoxicity was evaluated on malignant cell lines (A549, CACO-2, HCT-15, MCF-7, NCI-H226, PC-3, SH-SY5Y, and SK-MEL-28) using the MTT and LDH assays. The ability of compounds to stimulate the production of hydrogen peroxide (H2O2) and to induce mitochondrial dysfunction, the externalization of phosphatidylserine, Caspase-9 activity, and changes in nuclear morphology was also studied on MCF-7 cells. The ability to induce DNA damage was also studied on L929 fibroblasts. The proteasome inhibitory activity was estimated through molecular docking studies. The compounds exhibited IC50 values between 15.35 and 53.34 μM. 12Rhydroxy-bromosphaerol and 12S-hydroxy-bromosphaerol increased the H2O2 levels on MCF-7 cells, and bromosphaerol induced DNA damage on fibroblasts. All compounds promoted a depolarization of mitochondrial membrane potential, Caspase-9 activity, and nuclear condensation and fragmentation. The compounds have been shown to interact with the chymotrypsin-like catalytic site through molecular docking studies; however, only 12S-hydroxy-bromosphaerol evidenced interaction with ALA20 and SER169, key residues of the proteasome catalytic mechanism. Further studies should be outlined to deeply characterize and understand the potential of those bromoditerpenes for anticancer therapeutics.

2022Journal article

Open access

Synthesis of emerging cathinones and validation of a SPE GC–MS method for their simultaneous quantification in blood

Publication . Júlio, Sara; Ferro, Raquel A.; Santos, Susana; Alexandre, Andrea; Caldeira, Maria João; Franco, João; Barroso, Mário; Gaspar, Helena

Over the past 15 years, synthetic cathinones have emerged as an important class of new psychoactive substances (NPS) worldwide. The proliferation of these psychostimulants and their sought-after effects among recreational drug users pose a serious threat to public health and enormous challenges to forensic laboratories. For forensic institutions, it is essential to be one step ahead of covert laboratories, foreseeing the structural changes possible to introduce in the core skeleton of cathinones while maintaining their stimulating activity. In this manner, it is feasible to equip themselves with standards of possible new cathinones and validated analytical methods for their qualitative and quantitative detection. Therefore, the aim of the work herein described was to synthesize emerging cathinones based on the evolving patterns in the illicit drug market, and to develop an analytical method for their accurate determination in forensic situations. Five so far unreported cathinones [4′-methyl-N-dimethylbuphedrone (4-MDMB), 4′-methyl-N-ethylbuphedrone (4-MNEB), 4′-methyl-N-dimethylpentedrone (4-MDMP), 4′-methyl-N-dimethylhexedrone (4-MDMH), and 4′-methyl-N-diethylbuphedrone (4-MDEB)] and a sixth one, 4′-methyl-N-ethylpentedrone, already reported to EMCDDA and also known as 4-MEAP, were synthesized and fully characterized by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). An analytical method for the simultaneous quantification of these cathinones in blood, using solid phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC–MS) was developed and validated. The results prove that this methodology is selective, linear, precise, and accurate. For all target cathinones, the extraction efficiency was higher than 73%, linearity was observed in the range of 10 (lower limit of quantification, LLOQ) to 800 ng/mL, with coefficients of determination higher than 0.99, and the limits of detection (LODs) were 5 ng/mL for all target cathinones. The stability of these cathinones in blood matrices is dependent on the storage conditions; 4-MNEB is the most stable compound and 4-MDMH is the least stable compound. The low limits obtained allow the detection of the compounds in situations where they are involved, even if present at low concentrations.

2023Journal article

Restricted access

Mitigating the negative impacts of marine invasive species – Sargassum muticum - a key seaweed for skincare products development

Publication . Susano, Patrícia; Silva, Joana; Alves, Celso; Martins, Alice; Pinteus, Susete; Gaspar, Helena; Goettert, Márcia Inês; Pedrosa, Rui

Sargassum 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.

2022Journal article

Restricted access