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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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Targeted metabolites and biological activities of Cydonia oblonga Miller leavesPublication . Oliveira, Andreia P.; Costa, Rossana M.; Magalhães, Ana S.; Pereira, José A.; Carvalho, Márcia; Valentão, Patrícia; Andrade, Paula B.; Silva, Branca M.Natural products continue to play a significant role in drug discovery and development processes, and many plants have already provided valuable clues for potentially bioactive compounds. Additionally, in recent years it has become evident that significant health risks and benefits are associated with dietary food choice. Nutritional studies recommend the regular consumption of fruits and vegetables, which constitute an essential part of the Mediterranean diet, to favor a healthy life. Several works have showed that quince tree (Cydonia oblonga Miller) is a good and low cost natural source of metabolites with interesting biological properties. Extensive research has been performed on the metabolic profile and biological potential of this species. In particular, quince leaves revealed to constitute a promising natural source of bioactive phytochemicals, suitable for application in nutritional/pharmaceutical fields. In this review phenolics and organic acids composition of quince leaf is overviewed, as well as its antioxidant and antiproliferative properties, in chemical and cellular in vitro systems. Comparisons with green tea, considered by the scientific community as an effective natural antioxidant, were established.
- 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.
- 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.