Browsing by Author "Silva, Branca M."
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- Destaques das "I Jornadas sobre intoxicações - intoxicações, interacções e reacções adversas a medicamentos"Publication . Pimenta, Adriana; Silva, Branca M.; Carvalho, Márcia; Souto, Renata; Catarino, RitaAs “i jornadas sobre intoxicações - intoxicações, interacções e reacções Adversas a medicamentos” reuniram alguns profissionais do nosso país que partilharam experiências e conhecimentos com o objectivo de contribuir para minimizar a incidência e/ou gravidade das reacções adversas a fármacos. neste artigo pretende-se compilar a informação partilhada durante as jornadas e aprofundá-la, contribuindo para que os profisionais de saúde possam evitar e/ou reconhecer a ocorrência de reacções adversas e interacções decorrentes do uso de medicamentos. The “i meeting About intoxications - intoxications, interactions and Adverse reactions to Drugs” was held to bring expertises from around the country together to find answers and share experience in order to minimize the incidence and severity of drug interactions, intoxications and side effects. the information shared in the meeting and here analysed is intended to help health professionals in avoiding and recognizing drug interactions and adverse reactions.
- 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.
- 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).
- 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.
- Estudo preliminar da actividade antimicrobiana das folhas de cydonia oblonga millerPublication . Filipe, Catarina; Silva, Ricardo; Miranda, Ana; Oliveira, Andreia P.; Silva, Branca M.; Sousa, João Carlos; Cerqueira, FátimaO marmelo é reconhecido como uma importante fonte de compostos promotores da saúde sendo que a actividade antimicrobiana dos extractos da sua polpa, casca e sementes foi já avaliada. Não existem porém estudos da actividade antimicrobiana das folhas de marmeleiro. Este estudo preliminar teve como objectivo determinar a actividade dos seus extractos metanólicos. Concluiu-se que os extractos testados não apresentam actividade em E. coli, S. aureus, C. albicans, C. glabrata, A. niger, A. fumigatus, Mucor spp e Absídia spp pelo que novos extractos devem ser preparados sendo posteriormente avaliados. Quince fruit is recognized an important source of health promoting compounds being the antimicrobial activities of the quince pulp, peel grape and seed extracts already evaluated. No results are known for quince leaves antimicrobial activity. This preliminary work intended to determine the activity of quince leaves methanolic extracts. These had no antimicrobial activity either against E. coli, S. aureus, C. albicans, C. glabrata, A. niger, A. fumigatus, Mucor spp e Absídia spp and new extracts must be prepared and evaluated.
- Evaluation of free radical-scavenging and antihemolytic activities of quince (Cydonia oblonga) leaf: a comparative study with green tea (Camellia sinensis)Publication . Costa, Rossana M.; Magalhães, Ana S.; Pereira, José A.; Andrade, Paula B.; Valentão, Patrícia; Carvalho, Márcia; Silva, Branca M.This study aimed to determine the phenolic profile and to investigate the antioxidant potential of quince (Cydonia oblonga) leaf, comparing it with green tea (Camellia sinensis). For these purposes, methanolic extracts were prepared and phenolics content of quince leaf was determined by HPLC/UV. The antioxidant properties were assessed by Folin-Ciocalteu reducing capacity assay and 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.5-O-Caffeoylquinic acid was found to be the major phenolic compound in quince leaf extract. Quince leaf exhibited a significantly higher reducing power than green tea (mean value of 227.8 +/- 34.9 and 112.5 +/- 1.5 g/kg dry leaf, respectively). Quince leaf extracts showed similar DPPH radical-scavenging activities (EC50 mean value of 21.6 +/- 3.5 microg/ml) but significantly lower than that presented by green tea extract (EC50 mean value of 12.7 +/- 0.1 microg/ml). Under the oxidative action of AAPH, quince leaf methanolic extract significantly protected the erythrocyte membrane from hemolysis in a similar manner to that found for green tea (IC50 mean value of 30.7 +/- 6.7 and 24.3 +/- 9.6 microg/ml, respectively, P > 0.05). These results point that quince leaf may have application as preventive or therapeutic agent in diseases in which free radicals are involved.
- First report on Cydonia oblonga Miller anticancer potential: differential antiproliferative effect against human kidney and colon cancer cellsPublication . Carvalho, Márcia; Silva, Branca M.; Silva, Renata; Valentão, Patrícia; Andrade, Paula B.; Bastos, Maria L.The present study reports the phenolic profile and antiproliferative properties of quince (Cydonia oblonga Miller) leaf and fruit (pulp, peel, and seed) against human kidney and colon cancer cells. The phenolic profiles of quince methanolic extracts were determined by high-performance liquid chromatography (HPLC)/diode array detector (DAD). 5-O-Caffeoylquinic acid was always one of the two major phenolic compounds present in all extracts, except for seed. Our results revealed that quince leaf and fruit extracts exhibited distinctive antiproliferative activities. The extracts from quince leaf showed concentration-dependent growth inhibitory activity toward human colon cancer cells (IC(50) = 239.7 +/- 43.2 microg/mL), while no effect was observed in renal adenocarcinoma cells. Concerning the fruit, seed extracts exhibited no effect on colon cancer cell growth, whereas strong antiproliferative efficiency against renal cancer cells was observed for the highest concentration assayed (500 microg/mL). The antiproliferative activity of pulp and peel extracts was low or absent in the selected range of extract concentrations. This is the first report showing that C. oblonga may be useful as a cancer chemopreventive and/or chemotherapeutic agent.
- Green tea: a promising anticancer agent for renal cell carcinomaPublication . Carvalho, Márcia; Jerónimo, Carmen; Valentão, Patrícia; Andrade, Paula B.; Silva, Branca M.Renal cell carcinoma (RCC) is one of the most lethal amongst the urologic malignancies, comprising three percent of all human neoplasms, and its incidence appears to be rising. RCC is refractory to both chemotherapy and radiotherapy. Therefore, the discovery of new strategies for therapeutic intervention remains a priority. Green tea (Camellia sinensis) and tea polyphenols have been proposed to exert protective effects against several types of cancer, based on preclinical and clinical trial data; however, the anticarcinogenic activity of green tea towards RCC is unknown. In this study, a targeted metabolite analysis on a green tea leaves methanolic extract was performed by HPLC/DAD and the antiproliferative activity of the extract was assayed using human renal cancer cell lines A-498 and 769-P. The total phenolic content was very high (31.8% of methanolic extract), and the main compounds were flavan-3-ols (94.3% of the total phenolic content), and especially (−)-epigallocatechin-3-gallate (35.9% of the total phenolic content). In addition, two methylxanthines – theophylline and caffeine – were also present in the extract, caffeine being the most abundant. Green tea extract strongly inhibited the growth of both RCC cell lines in a concentration-dependent manner, with IC50 values of 54 ± 10 and 129 ± 28 μg/ml for A-498 and 769-P cells, respectively. This is the first report showing that green tea is likely to be an effective anticancer agent for renal cell carcinoma.
- 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.
- 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.