Browsing by Author "Andrade, Paula B."
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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.
- 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.
- A gas chromatography-mass spectrometry multi-target method for the simultaneous analysis of three classes of metabolites in marine organismsPublication . Pereira, David M.; Vinholes, Juliana; de Pinho, Paula Guedes; Valentao, Patricia; Mouga, Teresa; Teixeira, Natercia; Andrade, Paula B.In this work a fast and simple multi-target gas chromatography–mass spectrometry (GC–MS) method for the simultaneous detection and absolute quantification of amino acids, fatty acids and sterols in marine organisms is proposed. The methodology was applied to the characterization of the echinoderm Marthasterias glacialis Linnaeus spiny sea star extracts. The main factors influencing the extraction of target compounds were evaluated by using different extraction procedures, solvent systems and temperature conditions and a comparison with a reference technique was performed. The most suitable procedure, capable of successfully extract the three classes of target compounds, was ethanol as solvent at 40 1C under magnetic stirring. Good analytical parameters were obtained since calibrations curves for the 40 compounds under analysis (15 amino acids, 16 fatty acids and 9 sterols) showed regression coefficients (r 2 ) ranging from 0.9844 to 0.9978, with low RSD (from 0.00 to 9.45%), and detection limits varying from 0.03 to 15.40 mg/L. The RSD values for intra- and interday variations studies were also good (RSDo13.5%, for both) and recoveries were higher than 92%. Variation in samples from different harvests and origins and their chemical composition during the year is reported. The fact that no previous treatment of samples is required can make this a useful technique for metabolite profiling in marine organisms, among others, both in biomedical and nutritional studies. Moreover, due to the fast and robust character of the proposed method it seems to be suitable for the implementation as routine analysis.
- 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.
- 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.
- The biotechnological potential of Asparagopsis armata: what is known of its chemical composition, bioactivities and current market?Publication . Félix, Rafael; Dias, Pedro; Félix, Carina; Cerqueira, Teresa; Andrade, Paula B.; Valentão, Patricia; Lemos, Marco F.L.Marine biomass is a resource with great potential to fuel a circular bioeconomy addressing the current economic and environmental world crisis, while seaweeds are known to be a great source of bioactive compounds with potential use for human and animal nutrition, novel natural preservatives, phytopharmaceuticals, cosmeceuticals, biopharmaceuticals, among others. Asparagopsis armata (Harvey, 1855) is a seaweed with high biomass production and exquisite biotechnological potential due to a myriad of produced secondary metabolites. Furthermore, it is one of the most aggressive invasive seaweed species becoming an economic and ecological problem in Europe. Simultaneously, it is a resource with market demand for its applications in cosmetics and, more recently, for its potential anti-methanogenic activity in ruminants. There is an appreciable amount of literature concerning the chemistry and the bioactivity of this seaweed species (and particularly its gametophyte, the focus of this review), as well as multiple products in the cosmetics market, but all this information is scattered and therefore poorly used. To potentiate the bioindustry of A. armata, the available scientific knowledge is here reviewed and an overview of the market for this species is comprehensively provided. Thus, the chemical composition of A. armata (primary metabolism, polysaccharide characteristics, amino acid profile, and nonhalogenated and halogenated secondary metabolites), its bioactivities (antibacterial, antifungal, antiviral, antiprotozoal, antioxidant, antitumor, anti-inflammatory, among others) and the existent, marketed extracts (cosmetic ingredients) are thoroughly compiled and discussed herein.
- Valuable compounds in macroalgae extractsPublication . Andrade, Paula B.; Barbosa, Mariana; Matos, Rui Pedro; Lopes, Graciliana; Vinholes, Juliana; Mouga, Teresa; Valentão, PatríciaBioactive compounds present in ethanolic extracts from 18 macroalgae of the Portuguese coast were analysed by gas chromatography–mass spectrometry (GC–MS), leading to the characterization of 14 compounds: proline, phloroglucinol, mannitol, 8 fatty acids and 3 sterols. A dose-dependent response against enzymes with biological significance (a-glucosidase, acetylcholinesterase and butyrylcholinesterase) and free radicals (DPPH, nitric oxide, superoxide and hydroxyl) was found, Phaeophyta being the most promising group. A PCA analysis was performed and allowed the establishment of a correlation between the algae chemical composition and the biological activity. Cystoseira tamariscifolia (Hudson) Papenfuss, Cystoseira nodicaulis (Withering) M. Roberts, Cystoseira usneoides (Linnaeus) M. Roberts and Fucus spiralis Linnaeus are among the most active species, which is in accordance with their higher contents in phloroglucinol, mannitol, oleic, arachidonic and eicosapentaenoic acids, and fucosterol. The results point to the potential interest of the use of Phaeophyta species as food additives, due to their potent antiradical activities, and especially highlights the importance of F. spiralis in the food chain of Mediterranean countries. Moreover, the incorporation of the extracts of these species in food products, nutraceutical and pharmaceutical preparations for human health should also be instigated, since they can suppress hyperglycemia and inhibit cholinesterases.