Strategic Project - LA 6 - 2011-2012

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Publications

Valuable compounds in macroalgae extracts

Publication . Andrade, Paula B.; Barbosa, Mariana; Matos, Rui Pedro; Lopes, Graciliana; Vinholes, Juliana; Mouga, Teresa; Valentão, Patrícia

Bioactive 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.

2013Journal article

Restricted access

Phlorotannin Extracts from Fucales Characterized by HPLC-DAD-ESI-MSn: Approaches to Hyaluronidase Inhibitory Capacity and Antioxidant Properties

Publication . Ferreres, Federico; Lopes, Graciliana; Gil-Izquierdo, Angel; Andrade, Paula; Sousa, Carla; Mouga, Teresa; Valentão, Patrícia

Purified 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.

2012Journal article

Open access

A gas chromatography-mass spectrometry multi-target method for the simultaneous analysis of three classes of metabolites in marine organisms

Publication . 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.

2012Journal article

Restricted access

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

Bacterial 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.

2012Journal article

Open access