Percorrer por autor "Valentão, Patrícia"
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- Can Phlorotannins Purified Extracts Constitute a Novel Pharmacological Alternative for Microbial Infections with Associated Inflammatory Conditions?Publication . Lopes, Graciliana; Sousa, Carla; Silva, Luís R.; Pinto, Eugénia; Andrade, Paula B.; Bernardo, João; Mouga, Teresa; Valentão, PatríciaBacterial and fungal infections and the emerging multidrug resistance are driving interest in fighting these microorganisms with natural products, which have generally been considered complementary to pharmacological therapies. Phlorotannins are polyphenols restricted to brown seaweeds, recognized for their biological capacity. This study represents the first research on the antibacterial, antifungal, anti-inflammatory and antioxidant activity of phlorotannins purified extracts, which were obtained from ten dominant brown seaweeds of the occidental Portuguese coast. Phlorotannins content was determined by the specific dimethoxybenzaldehyde (DMBA) method and a yield between 75 and 969 mg/Kg phloroglucinol units (dry matter) was obtained. Fucus spiralis ranked first, followed by three Cystoseira species. The antiinflammatory potential of the purified extracts was assessed via inhibitory effect on nitric oxide (NO) production by lipopolysaccharide-stimulated RAW 264.7 macrophage cells, Cystoseira tamariscifolia being the one showing promising activity for the treatment of inflammation. NO scavenging ability was also addressed in cell free systems, F. spiralis being the species with highest capacity. The antimicrobial potential of the extracts was checked against five Gram-positive and four Gram-negative bacteria and three fungi strains, that commonly colonize skin and mucosa and are responsible for food contamination. The different extracts were more effective against Gram-positive bacteria, Staphylococcus epidermidis being the most susceptible species. Concerning antifungal activity, Trichophyton rubrum was the most sensitive species. Although the molecular mechanisms underlying these properties remain poorly understood, the results obtained turn phlorotannins purified extracts a novel and potent pharmacological alternative for the treatment of a wide range of microbial infections, which usually also present an inflammatory component. In addition to the biological properties demonstrated herein, phlorotannins extracts may also be preferred, in order to avoid side effects and allergic reactions commonly associated with synthetic drugs.
- Can Phlorotannins Purified Extracts Constitute a Novel Pharmacological Alternative for Microbial Infections with Associated Inflammatory Conditions?Publication . Lopes, Graciliana; Sousa, Carla; Silva, Luís R.; Pinto, Eugénia; Andrade, Paula B.; Bernardo, João; Mouga, Teresa; Valentão, Patrícia; Mande HolfordBacterial and fungal infections and the emerging multidrug resistance are driving interest in fighting these microorganisms with natural products, which have generally been considered complementary to pharmacological therapies. Phlorotannins are polyphenols restricted to brown seaweeds, recognized for their biological capacity. This study represents the first research on the antibacterial, antifungal, anti-inflammatory and antioxidant activity of phlorotannins purified extracts, which were obtained from ten dominant brown seaweeds of the occidental Portuguese coast. Phlorotannins content was determined by the specific dimethoxybenzaldehyde (DMBA) method and a yield between 75 and 969 mg/Kg phloroglucinol units (dry matter) was obtained. Fucus spiralis ranked first, followed by three Cystoseira species. The anti-inflammatory potential of the purified extracts was assessed via inhibitory effect on nitric oxide (NO) production by lipopolysaccharide-stimulated RAW 264.7 macrophage cells, Cystoseira tamariscifolia being the one showing promising activity for the treatment of inflammation. NO scavenging ability was also addressed in cell free systems, F. spiralis being the species with highest capacity. The antimicrobial potential of the extracts was checked against five Gram-positive and four Gram-negative bacteria and three fungi strains, that commonly colonize skin and mucosa and are responsible for food contamination. The different extracts were more effective against Gram-positive bacteria, Staphylococcus epidermidis being the most susceptible species. Concerning antifungal activity, Trichophyton rubrum was the most sensitive species. Although the molecular mechanisms underlying these properties remain poorly understood, the results obtained turn phlorotannins purified extracts a novel and potent pharmacological alternative for the treatment of a wide range of microbial infections, which usually also present an inflammatory component. In addition to the biological properties demonstrated herein, phlorotannins extracts may also be preferred, in order to avoid side effects and allergic reactions commonly associated with synthetic drugs.
- Codium tomentosum and Plocamium cartilagineum: Chemistry and antioxidant potentialPublication . Valentão, Patrícia; Trindade, Pedro; Gomes, Daniela; Pinho, Paula Guedes de; Mouga, Teresa; Andrade, Paula B.The chemical composition of green Codium tomentosum Stackhouse and red Plocamium cartilagineum (Linnaeus) P.S. Dixon seaweeds from the Atlantic Ocean surrounding Portugal was studied. For the first time, the profile of organic acids was analysed in these matrices: seven and four organic acids were detected in green and red species, respectively. In P. cartilagineum these compounds were present in vestigial amounts, whilst C. tomentosum exhibited a higher content, with oxalic acid being the main compound. Phenolics, UV-absorbing compounds, were absent in both species. Volatiles profile was also determined for the first time and a total of 41 compounds were identified, which included alcohols, aldehydes, esters, halogenated compounds, ketones, monoterpenes (namely terrestrial ones), norisoprenoid derivatives, amongst others. Norisoprenoid derivatives and aldehydes were predominant. The main volatiles in green and red seaweeds were limonene and benzophenone, respectively. Additionally, both species revealed considerable antioxidant activity against both reactive oxygen (superoxide radical) and reactive nitrogen (nitric oxide) species, in a concentration-dependent manner.
- Evaluating the in vitro potential of natural extracts to protect lipids from oxidative damagePublication . Félix, Rafael; Valentão, Patrícia; Andrade, Paula B.; Félix, Carina; Novais, Sara C.; Lemos, Marco F.L.Lipid peroxidation is a chemical reaction known to have negative impacts on living organisms’ health and on consumer products’ quality and safety. Therefore, it has been the subject of extensive scientific research concerning the possibilities to reduce it, both in vivo and in nonliving organic matrices. It can be started by a variety of oxidants, by both ROS-dependent and -independent pathways, all of them reviewed in this document. Another feature of this reaction is the capacity of lipid peroxyl radicals to react with the non-oxidized lipids, propagating the reaction even in the absence of an external trigger. Due to these specificities of lipid peroxidation, regular antioxidant strategies—although being helpful in controlling oxidative triggers—are not tailored to tackle this challenge. Thus, more suited antioxidant compounds or technologies are required and sought after by researchers, either in the fields of medicine and physiology, or in product development and biotechnology. Despite the existence of several laboratory procedures associated with the study of lipid peroxidation, a methodology to perform bioprospecting of natural products to prevent lipid peroxidation (a Lipid Peroxidation Inhibitory Potential assay, LPIP) is not yet well established. In this review, a critical look into the possibility of testing the capacity of natural products to inhibit lipid peroxidation is presented. In vitro systems used to peroxidize a lipid sample are also reviewed on the basis of lipid substrate origin, and, for each of them, procedural insights, oxidation initiation strategies, and lipid peroxidation extent monitoring are discussed.
- HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling of cytotoxic carotenoids from the echinoderm Marthasterias glacialis (spiny sea-star)Publication . Ferreres, Federico; Pereira, David M.; Gil-Izquierdo, Angel; Valentão, Patrícia; Botelho, João; Mouga, Teresa; Andrade, Paula B.An HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling analysis was conducted on the marine echinoderm Marthasterias glacialis (spiny sea-star). Bio-guided purification of the methanolic extract led to the isolation of several carotenoids, namely zeaxanthin, astaxanthin and lutein. These compounds were characterized using both UV–Vis characteristics and MS spectra interpretation. No previous works addressed the MS analysis of carotenoids present in this organism. The purified carotenoid fraction displayed a strong cell proliferation inhibition against rat basophilic leukemia RBL-2H3 (IC25 5 268 mg/mL) cancer cell line. Against healthy V79 (rat lung fibroblasts (IC25 5411 mg/mL)) cell line, however, toxicity was lower, as it is desired for anti-cancer molecules. This study suggests that M. glacialis may constitute a good source of bioactive compounds that can be used as lead compounds for the pharmaceutical industry.
- Marine macroalgae, a source of natural inhibitors of Fungal PhytopathogensPublication . Vicente, Tânia F. L.; Lemos, Marco F.L.; Valentão, Patrícia; Félix, Rafael; Félix, CarinaFungal phytopathogens are a growing problem all over the world; their propagation causes significant crop losses, affecting the quality of fruits and vegetables, diminishing the availability of food, leading to the loss of billions of euros every year. To control fungal diseases, the use of synthetic chemical fungicides is widely applied; these substances are, however, environmentally damaging. Marine algae, one of the richest marine sources of compounds possessing a wide range of bioactivities, present an eco-friendly alternative in the search for diverse compounds with industrial applications. The synthesis of such bioactive compounds has been recognized as part of microalgal responsiveness to stress conditions, resulting in the production of polyphenols, polysaccharides, lipophilic compounds, and terpenoids, including halogenated compounds, already described as antimicrobial agents. Furthermore, many studies, in vitro or in planta, have demonstrated the inhibitory activity of these compounds with respect to fungal phytopathogens. This review aims to gather the maximum of information addressing macroalgae extracts with potential inhibition against fungal phytopathogens, including the best inhibitory results, while presenting some already reported mechanisms of action.
- Phlorotannin Extracts from Fucales Characterized by HPLC-DAD-ESI-MSn: Approaches to Hyaluronidase Inhibitory Capacity and Antioxidant PropertiesPublication . Ferreres, Federico; Lopes, Graciliana; Gil-Izquierdo, Angel; Andrade, Paula; Sousa, Carla; Mouga, Teresa; Valentão, PatríciaPurified phlorotannin extracts from four brown seaweeds (Cystoseira nodicaulis (Withering) M. Roberts, Cystoseira tamariscifolia (Hudson) Papenfuss, Cystoseira usneoides (Linnaeus) M. Roberts and Fucus spiralis Linnaeus), were characterized by HPLC-DAD-ESI-MSn . Fucophloroethol, fucodiphloroethol, fucotriphloroethol, 7-phloroeckol, phlorofucofuroeckol and bieckol/dieckol were identified. The antioxidant activity and the hyaluronidase (HAase) inhibitory capacity exhibited by the extracts were also assessed. A correlation between the extracts activity and their chemical composition was established. F. spiralis, the species presenting higher molecular weight phlorotannins, generally displayed the strongest lipid peroxidation inhibitory activity (IC50 = 2.32 mg/mL dry weight) and the strongest HAase inhibitory capacity (IC50 = 0.73 mg/mL dry weight). As for superoxide radical scavenging, C. nodicaulis was the most efficient species (IC50 = 0.93 mg/mL dry weight), followed by F. spiralis (IC50 = 1.30 mg/mL dry weight). These results show that purified phlorotannin extracts have potent capabilities for preventing and slowing down the skin aging process, which is mainly associated with free radical damage and with the reduction of hyaluronic acid concentration, characteristic of the process.
- Red seaweed-derived compounds as a potential new approach for acne vulgaris carePublication . Januário, Adriana P.; Félix, Rafael; Félix, Carina; Reboleira, João; Valentão, Patrícia; Lemos, Marco F.L.Acne vulgaris (AV) is a chronic skin disease of the pilosebaceous unit affecting both adolescents and adults. Its pathophysiology includes processes of inflammation, increased keratinization, sebum production, hormonal dysregulation, and bacterial Cutibacterium acnes proliferation. Common AV has been treated with antibiotics since the 1960s, but strain resistance has emerged and is of paramount concern. Macroalgae are known producers of substances with bioactive properties, including anti-viral, antibacterial, antioxidant, and anti-inflammatory properties, among several others. In particular, red algae are rich in bioactive compounds such as polysaccharides, phenolic compounds, lipids, sterols, alkaloids, and terpenoids, conferring them antioxidant, antimicrobial, and anti-inflammatory activities, among others. Thus, the exploration of compounds from marine resources can be an appealing approach to discover new treatment options against AV. The aim of this work is to provide an overview of the current knowledge of the potentialities of red macroalgae in the treatment of AV by reviewing the main therapeutic targets of this disease, and then the existence of compounds or extracts with bioactive properties against them.
- Seaweed as a natural source against phytopathogenic bacteriaPublication . Vicente, Tânia F.L.; Félix, Carina; Félix, Rafael; Valentão, Patrícia; Lemos, Marco F.L.Plant bacterial pathogens can be devastating and compromise entire crops of fruit and vegetables worldwide. The consequences of bacterial plant infections represent not only relevant economical losses, but also the reduction of food availability. Synthetic bactericides have been the most used tool to control bacterial diseases, representing an expensive investment for the producers, since cyclic applications are usually necessary, and are a potential threat to the environment. The development of greener methodologies is of paramount importance, and some options are already available in the market, usually related to genetic manipulation or plant community modulation, as in the case of biocontrol. Seaweeds are one of the richest sources of bioactive compounds, already being used in different industries such as cosmetics, food, medicine, pharmaceutical investigation, and agriculture, among others. They also arise as an eco-friendly alternative to synthetic bactericides. Several studies have already demonstrated their inhibitory activity over relevant bacterial phytopathogens, some of these compounds are known for their eliciting ability to trigger priming defense mechanisms. The present work aims to gather the available information regarding seaweed extracts/compounds with antibacterial activity and eliciting potential to control bacterial phytopathogens, highlighting the extracts from brown algae with protective properties against microbial attack.
- Sterol profiles in 18 macroalgae of the Portuguese coastPublication . Lopes, Graciliana; Sousa, Carla; Bernardo, João; Andrade, Paula B.; Valentão, Patrícia; Ferreres, Federico; Mouga, TeresaThe sterol profiles of dominant macroalgae occur-ring in the western Portuguese coast were evaluated.An analytical procedure, involving alkaline hydrolysisand extraction followed by separation by reversed-phase HPLC–diode array detection (HPLC–DAD),was optimized for the study of their sterols composi-tion. The validated methodology is short in analysistime (as the compounds are determined in <20 min),sensitive, reproducible, and accurate. It was thensuccessfully applied to the determination of campes-terol, cholesterol, desmosterol, ergosterol, fucosterol,stigmasterol, andb-sitosterol in 18 species (threeChlorophyta, five Rhodophyta, and 10 Phaeophyta).The profiles obtained for the several macroalgalspecies were considerably different. C29 sterolswere predominant in Phaeophyta and Chlorophyta(71%–95% of total sterol content), while in Rhodo-phyta cholesterol content is significantly higher(34%–87%). Among the studied species,AsparagopsisarmataHarv. contained the lowest sterol amount(555 mgÆkg)1dry weight), andCystoseira tamariscifo-lia(Huds.) Papenf. the highest one (6,502 mgÆkg)1dry weight). Data obtained may be helpful inidentifying suitable marine sources of sterols, withpotential applications in the food and pharmaceutical industries.