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- Phytochemical profiles and inhibitory effect on free radical-induced human erythrocyte damage of Dracaena draco leaf: a potential novel antioxidant agentPublication . Santos, Rui P.; Mendes, Lídia S.; Silva, Branca M.; Guedes de Pinho, Paula; Valentão, Patrícia; Andrade, Paula B.; Pereira, José A.; Carvalho, MárciaThe present study reports for the first time the metabolite profile and antioxidant activity of aqueous extract obtained from Dracaena draco L. leaf. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 34 compounds being identified, distributed by distinct chemical classes: 2 alcohols, 5 aldehydes, 16 carotenoid derivatives and 8 terpenic compounds. Carotenoid derivative compounds constituted the most abundant class in leaf (representing 45% of total identified compounds). Phenolics profile was determined by HPLC/DAD and 9 constituents were identified: 2 hydroxycinnamic acid derivatives – 5-O-caffeoylquinic and 3,5-O-dicaffeoylquinic acids; 4 hydroxycinnamic acids – caffeic, p-coumaric, ferulic and sinapic acids and 3 flavonol glycosides – quercetin-3-O-rutinoside, kaempferol-3-O-glucoside and kaempferol-3-O-rutinoside. The most abundant phenolic compound is quercetin-3-O-rutinoside (representing 50.2% of total polyphenols). Organic acids composition was also characterised, by HPLC–UV and oxalic, citric, malic and fumaric acids were determined. Oxalic and citric acids were present in higher amounts (representing 47%, each). The antioxidant potential of this material was assessed by the ability to protect against free radical-induced biomembrane damage, using human erythrocyte as in vitro model. Leaf extract strongly protected the erythrocyte membrane from haemolysis (IC50 of 39 ± 11 μg/ml), in a time- and concentration-dependent manner. This is the first report showing that D. draco leaf is a promising antioxidant agent.
- Marmelo (cydonia oblonga miller): fonte de compostos biologicamente activosPublication . Oliveira, Andreia; Silva, Branca M.O marmelo é consumido em grande quantidade no nosso país, sobretudo na forma de marmelada e geleia. na última década, a composição química deste fruto tem sido bastante estudada, tendo-se verificado que se trata de uma excelente fonte de compostos fenólicos e de ácidos orgânicos, compostos bioactivos com reconhecida actividade antioxidante. pretende-se incentivar o consumo do marmelo e alertar para a possibilidade de utilizar os desperdícios da indústria dos seus derivados para produzir novos fármacos que poderão vir a ser usados na prevenção de diversas doenças crónicas. Quince is highly consumed in our country, especially as jam and jelly. In the last decade, quince chemical composition has been studied by several authors, who have considered this fruit as an excellent source of phenolics and organic acids, bioactive compounds which are recognized as powerful antioxidants. In this revision, we intend to promote quince consumption and to alert for the possible use of its derivatives industry byproducts to produce new drugs that may have relevance in the prevention of chronic diseases.
- Human cancer cell antiproliferative and antioxidant activities of Juglans regia L.Publication . Carvalho, Márcia; Ferreira, Pedro J.; Mendes, Vanda S.; Silva, Renata; Pereira, José A.; Jerónimo, Carmen; Silva, Branca M.Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. Walnuts contain several phenolic compounds which are thought to contribute to their biological properties. The present study reports the total phenolic contents and antioxidant properties of methanolic and petroleum ether extracts obtained from walnut (Juglans regia L.) seed, green husk and leaf. The total phenolic contents were determined by the Folin-Ciocalteu method and the antioxidant activities assessed by the ability to quench the stable free radical 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and to inhibit the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of human erythrocytes. Methanolic seed extract presented the highest total phenolic content (116 mg GAE/g of extract) and DPPH scavenging activity (EC(50) of 0.143 mg/mL), followed by leaf and green husk. In petroleum ether extracts, antioxidant action was much lower or absent. Under the oxidative action of AAPH, all methanolic extracts significantly protected the erythrocyte membrane from hemolysis in a time- and concentration-dependent manner, although leaf extract inhibitory efficiency was much stronger (IC(50) of 0.060 mg/mL) than that observed for green husks and seeds (IC(50) of 0.127 and 0.121 mg/mL, respectively). Walnut methanolic extracts were also assayed for their antiproliferative effectiveness using human renal cancer cell lines A-498 and 769-P and the colon cancer cell line Caco-2. All extracts showed concentration-dependent growth inhibition toward human kidney and colon cancer cells. Concerning A-498 renal cancer cells, all extracts exhibited similar growth inhibition activity (IC(50) values between 0.226 and 0.291 mg/mL), while for both 769-P renal and Caco-2 colon cancer cells, walnut leaf extract showed a higher antiproliferative efficiency (IC(50) values of 0.352 and 0.229 mg/mL, respectively) than green husk or seed extracts. The results obtained herein strongly indicate that walnut tree constitute an excellent source of effective natural antioxidants and chemopreventive agents.
- Development of an HPLC/DAD method for determination of phenolic profile in portuguese olive fruitsPublication . Ferreira da Vinha, Ana; Andrade, Paula B.; Silva, Branca M.; Pereira, José A.; Valentão, Patrícia; Seabra, Rosa M.; Oliveira, M. BeatrizPolyphenolic compounds inliuence the sensorial properties of olive fruits and virgin olive oils and are imporlant markers for studying fruit characteristics of different cultivars and for controlling oil production processes . A few chromatographic methods have been used to study the phenolic compounds of olive fruit . This communication reports the development of a new HPLCIDAD methodology to separate, identify aml quanlily lhe phenolic compounds from Portuguese olive fruit cultivars (Cobrançosa, Madura/and Verdeal).
- Protective effect of quince (Cydonia oblonga Miller) fruit against oxidative hemolysis of human erythrocytesPublication . Magalhães, Ana S.; Silva, Branca M.; Pereira, José A.; Andrade, Paula B.; Valentão, Patrícia; Carvalho, MárciaThe aim of this study was to determine the phenolic content and evaluate the antioxidant activity of quince (Cydonia oblonga) fruit. For this purpose, fruits were separated into pulps, peels and seeds and methanolic extracts were prepared. The phenolic profiles were determined by HPLC/UV and antioxidant properties were studied for their ability to quench the stable free radical 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and to inhibit the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of human erythrocytes. The main phenolic compounds were 5-O-caffeoylquinic acid for pulp and peel (57% and 29%, respectively) and stellarin-2 for seed (18%). Total phenolics content was 2.5, 6.3 and 0.4g/kg of methanolic extract for pulp, peel and seed, respectively. Pulp and peel extracts showed similar DPPH free radical scavenging activities (EC(50) of 0.6 and 0.8 mg/ml, respectively), while seed extract presented much lower antioxidant potential (EC(50) of 12.2mg/ml). Under the oxidative action of AAPH, pulp and peel extracts showed significant protection of the erythrocyte membrane from hemolysis, in a time- and concentration-dependent manner. Seed extracts by themselves induced extensive hemolysis. These results indicate higher antioxidant activity for certain parts of quince fruit, namely pulp and peel, that may therefore represent accessible sources of natural antioxidants with potential application in nutritional/pharmaceutical fields, as preventive or therapeutic agents in diseases in which free radicals are implicated.
- Phenolic profiles of portuguese olive fruits (Olea europaea L.): influences of cultivar and geographical originPublication . Ferreira da Vinha, Ana; Ferreres, Federico; Silva, Branca M.; Valentão, Patrícia; Gonçalves, Ana; Pereira, José; Oliveira, M. Beatriz P.P.; Seabra, Rosa M.; Andrade, Paula B.The phenolic compounds present in 29 samples of olive fruits were analysed by reversed-phase HPLC/DAD and/or HPLC-DAD/ ESI-MS/MS. All samples were collected during the normal picking period for olive oil production, in north and central Portugal, and were obtained from 18 different olive cultivars. Two different extraction methods were necessary for the complete quantification of phenolic compounds, a methanolic extraction and an extraction which included a solid-phase extraction (SPE) cleaning step. The analyses showed that all samples presented a similar profile, which included at least six identified phenolic compounds: hydroxytyrosol, luteolin 7-O-glucoside, oleuropein, rutin, apigenin 7-O-glucoside and luteolin. Several samples also contained 5-O- caffeoylquinic acid, verbascoside, quercetin 3-O-rhamnoside, cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside. In all samples, hydroxytyrosol and oleuropein were the major compounds identified while, in general, rutin and luteolin 7-O- glucoside were the two main flavonoids. The influences of maturation index, nature of the cultivar and geographical origin are discussed.
- Dracaena draco L. fruit: phytochemical and antioxidant activity assessmentPublication . Silva, Branca M.; Santos, Rui P.; Mendes, Lídia S.; Guedes de Pinho, Paula; Valentão, Patrícia; Andrade, Paula B.; Pereira, José A.; Carvalho, MárciaThe present study reports for the first time the metabolite profile and antioxidant activity of aqueous extract obtained from Dracaena draco L. fruit. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 9 compounds being identified, distributed by several distinct chemical classes: 1 alcohol, 3 aldehydes, 2 carotenoid derivatives, and 3 terpenic compounds. Aldehydes constituted the most abundant class in this exotic berry, representing 59% of total identified volatile compounds. Phenolics profile was determined by HPLC/DAD and 5 constituents were identified: 5-O-caffeoylquinic, 3,5-O-dicaffeoylquinic, ferulic and sinapic acids, and quercetin-3-O-rutinoside. The major phenolic compound is quercetin-3-O-rutinoside, comprising 42% of the total phenolic content. Organic acids composition was also characterized, by HPLC-UV, and oxalic, citric, l-ascorbic, malic, quinic and shikimic acids were determined. The most abundant is quinic acid, representing 39% of the total organic acid content. The antioxidant potential of this matrix was assessed by (i) reducing power of Fe3+/ferricyanide complex, (ii) scavenging effect on DPPH free radicals, and (iii) ability to inhibit the 2,2´-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis in human erythrocytes. Strawberry (Fragaria × ananassa Duch. cv. Camarosa) extract was used for comparison purposes. All assay models showed remarkable concentration dependent antioxidant activity, reducing power and radical scavenging efficiency for D. draco fruit, being invariably higher than that of strawberry extract. This is the first report showing that D. draco fruit is a promising new antioxidant agent.
- O perfil fenólico como parâmetro de autenticidade de derivados de marmeloPublication . Silva, Branca M.; Oliveira, Andreia P.Frequentemente, a indústria dos derivados de marmelo usa outros frutos na confecção dos mesmos. A pêra e a maçã são as mais utilizadas para o efeito, por serem facilmente acessíveis, de baixo custo e terem uma textura semelhante à do marmelo. Também é comum a utilização de frutos por descascar na produção de marmeladas, embora tal não seja permitido pela legislação Portuguesa. Pretende-se demonstrar a utilidade da determinação do perfil fenólico na avaliação da autenticidade de derivados do marmelo. Frequently, quince products industry uses other fruits in its manufacture. Pear and apple seem to be the most used for this effect, once they are easily accessible, of low cost and have a similar texture of quince. Unpeeled fruits utilization is also very usual in the production of quince jams, although not allowed by Portuguese legislation. In this revision paper, we intend to demonstrate the great utility of phenolic profile determination in the evaluation of quince derivatives authenticity.
- Development and evaluation of an HPLC-DAD method for the phenolic compounds from olive fruitsPublication . Ferreira da Vinha, Ana; Silva, Branca M.; Andrade, Paula B.; Seabra, Rosa M.; Pereira, José A.; Oliveira, M. Beatriz P.P.A new HPLC=DAD methodology for separating nine phenolic compounds is described. This methodology is applied to the definition of qualitative and quantitative profiles of three Portuguese olive fruit cultivars (Cobranc¸osa, Madural and Verdeal). Two different extraction methods were needed for the complete definition of their profiles, one of them including a Sep-pack C18 cleaning step.The chromatographic separation was achieved using a Spherisorb ODS2 (25.060.46 cm; 5 mm, particle size) column.The solvent system used was a gradient of water-formic acid (19:1) and methanol, with a flow rate of 0.9 mL=min. The detection limit values for phenolic compounds were between 0.04 and 4.32 mg=mL and the method was precise. As ageneral rule, the recovery values were high. This technique can also be useful in the discrimination of Portuguese olive fruit cultivars.
- Recent patents on Camellia sinensis: source of health promoting compoundsPublication . Moderno, Patrícia M.; Carvalho, Márcia; Silva, Branca M.In recent years, the scientific community, food industry, consumers and media have revealed a growing interest regarding the potential benefits of tea consumption for human health. Several studies indicate that phenolic compounds, especially flavan-3-ols (catechins), are the main components responsible for the medicinal effects of this beverage due to their recognized antioxidant properties. Antioxidants are ascribed to reduce cells and biomolecules oxidative damage caused by reactive oxygen/nitrogen species (ROS/RNS). In fact, ROS and RNS have been implicated in the oxidative deterioration of food products, as well as in the pathogenesis of several chronic and/or ageing diseases such as atherosclerosis, diabetes mellitus, chronic inflammation, neurodegenerative disorders, including Alzheimer's disease, and certain types of cancer. (-)-Epigallocatechin-3-gallate, the main component of white and green teas, for which chemical synthesis is complex, not only possesses strong antiradicalar activity but also can inhibit nitration reactions, modulate carcinogen-metabolizing enzymes, trap ultimate carcinogens and inhibit cancer cell proliferation. The recent patents on the tea manufacture, extracts preparation and health-promoting properties are reviewed in this manuscript, especially in what concerns the chemopreventive and chemotherapeutic activities of tea polyphenols.