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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.
- Phenolic compounds in three portuguese olive fruits varietiesPublication . Ferreira da Vinha, Ana; Andrade, Paula B.; Silva, Branca M.; Pereira, José A.; Valentão, Patrícia; Seabra, Rosa M.; Oliveira, M. BeatrizThis book looks at the biosynthesis and significance of phytochemicals, their analysis and antioxidant behaviour, paying special attention to their anti-oxidant properties.
- 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.
- 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.
- 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.
- 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.
- 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.