Percorrer por autor "Martins, Alice"
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- 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.
- 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.
- Bioproducts from forest biomass II. Bioactive compounds from the steam-distillation by-products of Cupressus lusitanica Mill. and Cistus ladanifer L. wastesPublication . Tavares, Cláudia S.; Martins, Alice; Miguel, M. Graça; Carvalheiro, Florbela; Duarte, Luís C.; Gameiro, José A.; Figueiredo, A. Cristina; Roseiro, Luísa B.Obtaining essential oils and hydrolates from underutilized biomass is an economic and sustainable way for production of these high added-value bioproducts. However, this process still generates large amounts of residues as the by-products obtained during distillation, which can be a concern for the environment, but also adequate substrates for other applications. Considering this fact, the waste distilled by-products remaining after steam-distillation of underutilized biomass from Cupressus lusitanica and Cistus ladanifer, were evaluated as a natural source of other high value products with biological activities, namely, phenolic compounds. Thus, the remaining extracted solid residues (ESRs) were characterized and subject to further treatments by ultrasound-assisted extraction (UAE) with ethanol and 70 % acetone, in order to prepare phenolic-rich extracts thereof: ESRs(EtOH) and ESRs(70 % Ace). Together with the distiller condensation waters (DCWs), these extracts were characterized for their phenolic content (total phenols, tannins and flavonoids). Their antioxidant activity was also evaluated by different methodologies. The phenolic profile of DCWs, ESRs(EtOH) and ESRs(70 % Ace) from both waste species was obtained by capillary zone electrophoresis (CZE) and phenolic compounds were tentatively identified. Results obtained for C. lusitanica biomass are here disclosed for the first time. Generally, all samples revealed to be rich in phenolic compounds, being C. ladanifer biomass the one with higher phenolic content. DCWs presented values of 140 mgGAE/g for C. lusitanica and 210 mg GAE/g for C. ladanifer, from which ca. 60 % were tannins. Extracts obtained with 70 % acetone were the ones with the highest results, except for the antioxidant activity by xanthine oxidase and superoxide inhibition, which was higher in DCWs. Catechins were the major compounds found for both species, but gallocatechins and gallic acid were only identified in C. ladanifer. Hydroxycinnamic acid derivatives and salicylic acid were also identified in C. ladanifer, partly justifying the anti-inflammatory effect referred for this species.
- Bioproducts from forest biomass: Essential oils and hydrolates from wastes of Cupressus lusitanica Mill. and Cistus ladanifer L.Publication . Tavares, Cláudia S.; Martins, Alice; Faleiro, M. Leonor; Miguel, M. Graça; Duarte, Luís C.; Gameiro, José A.; Roseiro, Luísa B.; Figueiredo, A. CristinaUnattended forest wastes are, among others, a potential source of wildfires, as well as a growth media for forest pests. As a way of lowering the detrimental effect of these wastes, it is important to convert these under-valued resources into a value-generating market forest wastes use. Essential oils (EOs) and hydrolates (Hs) from Cupressus lusitanica and Cistus ladanifer waste products, resulting from forest landscaping in Portugal, were evaluated for chemical composition and biological activity. Essential oils and Hs were obtained by steam-distillation (SD) and hydrodistillation (HD). Essential oils and Hs volatiles were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC–MS). The antimicrobial activity of EOs was studied by disk agar diffusion method against Escherichia coli, Staphylococcus aureus and Candida albicans. Antioxidant activity of EOs and Hs was evaluated by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical, superoxide anion radical formation, xanthine oxidase and chelating metal ions assays. Antiinflammatory activity of Hs was assessed by albumin denaturation assay. Monoterpene hydrocarbons and oxygen-containing monoterpenes dominated C. lusitanica EO (SD, 82–86 %, HD, 80–85 %) and Hs volatiles (SD, 93–94 %; HD 64–81 %), respectively. α-Pinene (14–36 %), limonene (8–21 %), δ-3-carene (8–19 %) and sabinene (6–18 %) were the main EO constituents. Hydrolates volatiles were dominated by cis-3-hexen-1-ol (0.1–13 %), camphor (1–11 %), umbellulone (t-48 %), p-cymene-8-ol (11–16 %) and terpinen-4-ol (21–31 %). C. ladanifer EOs were dominated by monoterpene hydrocarbons (SD, 48–80 % and HD, 29 %) and Hs by oxygencontaining monoterpenes (SD, 38–43 %, HD, 39 %). The EO major constituents were α-pinene (13–28 %) and camphene (5–25 %), whereas 2,6,6-trimethyl cyclohexanone (2–12 %) and trans-pinocarveol (5–13 %) dominated the Hs volatiles. This study reports for the first time the chemical composition of the hydrolate volatiles of these two species and their anti-inflammatory properties. Among the studied biological activities, the EOs showed the best antioxidant properties while Hs demonstrated higher anti-inflammatory activity.
- Deep Eutectic Systems: A Game Changer for Marine Bioactives RecoveryPublication . Amador, Sandro; Martins, Alice; Matias, Margarida; Pedrosa, Rui; Pinteus, SuseteThe extraction of bioactive compounds from marine natural products has gained increasing attention due to their diverse applications, such as in pharmaceuticals, nutraceuticals, and cosmetics. Yet, low extraction yields and toxicity associated with common solvents are a major bottleneck. Deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs) have emerged as promising green alternatives to conventional organic solvents, offering advantages such as biodegradability, greater environmental and economic sustainability, low toxicity, and enhanced extraction selectivity. This review provides a comprehensive analysis of the principles, physicochemical properties, and applications of DESs/NADESs to obtain bioactive compounds from marine organisms. Among the most recent works, it is possible to verify the success of NADESs to extract carrageenan from the seaweed Kappaphycus alvarezii; pigments from Palmaria palmata; and polyphenols and proteins from different brown seaweeds. NADESs have also shown high potential to extract other valuable compounds from marine by-products, such as chitin from crabs and shrimp shells, and also lipids and proteins from different fish species and protein rich extracts from tilapia viscera. The challenges for DESs/NADESs use at industrial scale are also discussed, and success cases are revealed, highlighting their potential as game changers for extracting bioactive compounds from marine organisms and driving the development of innovative biotechnological products.
- Disclosing the potential of eleganolone for Parkinson’s disease therapeutics: neuroprotective and anti-inflammatory activitiesPublication . Silva, Joana; Alves, Celso; Pinteus, Susete; Susano, Patrícia; Simões, Marco; Guedes, Miguel; Martins, Alice; Rehfeldt, Stephanie; Gaspar, Helena; Goettert, Márcia Inês; Alfonso, Amparo; Pedrosa, RuiThe treatment of Parkinson´s disease (PD) has benefited from significant advances resulting from the increasing research efforts focused on new therapeutics. However, the current treatments for PD are mostly symptomatic, alleviating disease symptoms without reversing or retarding disease progression. Thus, it is critical to find new molecules that can result in more effective treatments. Within this framework, this study aims to evaluate the neuroprotective and anti-inflammatory effects of three compounds (eleganolone, eleganonal and fucosterol) isolated from the brown seaweed Bifurcaria bifurcata. In vitro neuroprotective effects were evaluated on a PD cellular model induced by the neurotoxin 6-hydroxydopamine (6-OHDA) on SH-SY5Y human cells, while lipopolysaccharide (LPS) -stimulated RAW 264.7 macrophages were used to evaluate the anti-inflammatory potential. Additionally, the underlying mechanisms of action were also investigated. Compounds were isolated by preparative chromatographic methods and their structural elucidation attained by NMR spectroscopy. Among the tested compounds, eleganolone (0.1–1 μM; 24 h) reverted the neurotoxicity induced by 6-OHDA in about 20%. The neuroprotective effects were mediated by mitochondrial protection, reduction of oxidative stress, inflammation and apoptosis, and inhibition of NF-kB pathway. The results suggest that eleganolone may provide advantages in the treatment of neurodegenerative conditions and, therefore, should be considered for future preclinical studies.
- Exploring marine resources against neurological disorders: the neuroprotective and anti‑inflammatory potential of the brown seaweed Bifurcaria bifurcataPublication . Silva, Joana; Alves, Celso; Susano, Patrícia; Martins, Alice; Pinteus, Susete; Gaspar, Helena; Alfonso, Amparo; Pedrosa, RuiOxidative stress is strongly involved in the pathogenesis of neurodegenerative diseases, like Parkinson´s disease (PD). Particularly, an excess of reactive oxygen species (ROS) released by the cells promotes an oxidative stress condition, which is a main cause of tissue injury leading to nervous system dysfunction. In this work, the antioxidant, neuroprotective and antiinflammatory activities of different fractions from the brown seaweed Bifurcaria bifurcata are presented and related with their chemical profile. The antioxidant capacity was evaluated by the Folin-Ciocalteu method, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Neuroprotective capacity was evaluated to prevent neurological cell death mediated by the neurotoxin 6-hydroxydopamine (6-OHDA) on SH-SY5Y cells, and their anti-inflammatory effects on RAW 264.7 macrophages. The ethyl acetate fractions (100 μg mL−1) exhibited significant antioxidant and neuroprotective activities in the in vitro models assayed. Furthermore, two of the most polar fractions obtained with methanol and water also evidenced a significant neuroprotective potential. Bifurcaria bifurcata fractions treatment decreased ROS production, mitochondrial dysfunction, and Caspase-3 activity. Regarding the anti-inflammatory potential, five fractions (100 μg mL−1) inhibited nitric oxide (NO) production and reduced the interleukin – 6 (IL-6) and tumor necrosis factor (TNF-α) levels. Mannitol, identified as the major component of the most bioactive fraction, protected SH-SY5Y cells against the 6-OHDA neurotoxicity mediating ROS generation mitigation, mitochondrial dysfunction, and DNA damage, together with the Caspase-3 activity inhibition. Results suggest that B. bifurcata is a relevant source of neuroprotective agents, with particular interest for preventive therapeutics.
- 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.
- Highlighting the biological potential of the brown seaweed Fucus spiralis for skin applicationsPublication . Freitas, Rafaela; Martins, Alice; Silva, Joana; Alves, Celso; Pinteus, Susete; Alves, Joana; Teodoro, Fernando; Ribeiro, Helena Margarida; Gonçalves, Lídia; Petrovski, Zeljko; Branco, Luís; Pedrosa, RuiSkin 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.
- Loliolide, a new therapeutic option for neurological diseases? In vitro neuroprotective and anti-inflammatory activities of a monoterpenoid lactone isolated from codium tomentosumPublication . Silva, Joana; Alves, Celso; Martins, Alice; Susano, Patrícia; Simões, Marco; Guedes, Miguel; Rehfeldt, Stephanie; Pinteus, Susete; Gaspar, Helena; Rodrigues, Américo; Goettert, Márcia Inês; Alfonso, Amparo; Pedrosa, RuiParkinsons Disease (PD) is the second most common neurodegenerative disease worldwide, and is characterized by a progressive degeneration of dopaminergic neurons. Without an effective treatment, it is crucial to find new therapeutic options to fight the neurodegenerative process, which may arise from marine resources. Accordingly, the goal of the present work was to evaluate the ability of the monoterpenoid lactone Loliolide, isolated from the green seaweed Codium tomentosum, to prevent neurological cell death mediated by the neurotoxin 6-hydroxydopamine (6-OHDA) on SH-SY5Y cells and their anti-inflammatory effects in RAW264.7 macrophages. Loliolide was obtained from the diethyl ether extract, purified through column chromatography and identified by NMR spectroscopy. The neuroprotective effects were evaluated by the MTT method. Cells’ exposure to 6-OHDA in the presence of Loliolide led to an increase of cells’ viability in 40%, and this effect was mediated by mitochondrial protection, reduction of oxidative stress condition and apoptosis, and inhibition of the NF-KB pathway. Additionally, Loliolide also suppressed nitric oxide production and inhibited the production of TNF- and IL-6 pro-inflammatory cytokines. The results suggest that Loliolide can inspire the development of new neuroprotective therapeutic agents and thus, more detailed studies should be considered to validate its pharmacological potential.
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