Browsing by Author "Silva, Branca M."
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- Analysis and quantification of flavonoidic compounds from Portuguese olive (Olea europeae L.) leaf cultivarsPublication . Meirinhos, Julieta; Silva, Branca M.; Valentão, Patrícia; Seabra, Rosa M.; Pereira, J.A.; Dias, Alberto; Andrade, Paula B.; Ferreres, FredericoTwenty three samples of 18 Portuguese olive leaf cultivars were analysed by a reversed-phase HPLC/DAD procedure and eight flavonoidic compounds were identified and quantified (luteolin 7,40-O-diglucoside, luteolin 7-O-glucoside, rutin, apigenin 7-O-rutinoside, luteolin 40-O-glucoside, luteolin, apigenin and diosmetin). Luteolin 7,40-O-diglucoside and luteolin 40-O-glucoside were identified by HPLC/DAD/MS/MS – ESI. The studied olive leaf samples showed a common phenolic pattern, in which luteolin 40-O-glucoside was almost always the major compound
- Characterization of Ficus carica L. cultivars by DNA and secondary metabolites analysis: Is genetic diversity reflected in the chemical composition?Publication . Oliveira, Andreia P.; Baptista, Paula; Andrade, Paula B.; Martins, Fátima; Pereira, J.A.; Silva, Branca M.; Valentão, PatríciaFicus carica L. is one of the first plants cultivated by humans, having a great economic impact in many countries, the fruit being an important constituent of the Mediterranean diet. Plants' metabolome may be influenced by their genetic diversity, environmental factors and their interaction. Thus, in this study we explored the chemical and morphological profiles and the DNA of five Portuguese F. carica cultivars, to try to establish a correlation between genetics and metabolome. Morphological and molecular markers of these cultivars were assessed for the first time. Besides the observed morphological differences, the rbcL chloroplastic DNA region allowed a better clustering of the cultivars and was more successful in the identification of the species; as so, it could be helpful for authenticity purposes. Phenolic compounds, sterols and triterpenes profiles were determined by HPLC/DAD, the last revealing to be less variable among cultivars, once only a significant difference in the betulol content of “Pingo de Mel” samples was observed. For almost all the accessions studied, no correlation between genetic diversity and composition was observed.
- Chemical assessment and in vitro antioxidant capacity of Ficus carica latexPublication . Oliveira, Andreia P.; Silva, Luís R.; Ferreres, Frederico; Pinho, P. Guedes de; Valentão, Patrícia; Silva, Branca M.; Pereira, J.A.; Andrade, Paula B.Ficus species possess latex-like material within their vasculatures, affording protection and selfhealing from physical attacks. In this work, metabolite profiling was performed on Ficus carica latex. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 34 compounds being identified, distributed by distinct chemical classes: 5 aldehydes, 7 alcohols, 1 ketone, 9 monoterpenes, 9 sesquiterpenes and 3 other compounds. Sesquiterpenes constituted the most abundant class in latex (ca. 91% of total identified compounds). Organic acids composition was also characterized, by HPLC-UV, and oxalic, citric, malic, quinic, shikimic and fumaric acids were determined. Malic and shikimic acids were present in higher amounts (ca. 26%, each). The antioxidant potential of this material was checked by distinct in vitro chemical assays. A concentration-dependent activity was noticed against DPPH, nitric oxide and superoxide radicals. Additionally, acetylcholinesterase inhibitory capacity was evaluated, but a weak effect was found.
- Comparative study on free amino acid composition of wild edible mushroom speciesPublication . Ribeiro, Bárbara; Andrade, Paula B.; Silva, Branca M.; Baptista, Paula; Seabra, Rosa M.; Valentão, PatríciaA comparative study on the amino acid composition of 11 wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, and Cantharellus cibarius) was developed. To define the qualitative and quantitative profiles, a derivatization procedure with dabsyl chloride was performed, followed by HPLC-UV-vis analysis. Twenty free amino acids (aspartic acid, glutamic acid, asparagine, glutamine, serine, threonine, glycine, alanine, valine, proline, arginine, isoleucine, leucine, tryptophan, phenylalanine, cysteine, ornithine, lysine, histidine, and tyrosine) were determined. B. edulis and T. equestre were revealed to be the most nutritional species, whereas F. hepatica was the poorest. The different species exhibited distinct free amino acid profiles. The quantification of the identified compounds indicated that, in a general way, alanine was the major amino acid. The results show that the analyzed mushroom species possess moderate amino acid contents, which may be relevant from a nutritional point of view because these compounds are indispensable for human health. A combination of different mushroom species in the diet would offer good amounts of amino acids and a great diversity of palatable sensations
- Determination of low molecular weight volatiles in Ficus carica using HS-SPME and GC/FIDPublication . Oliveira, Andreia P.; Silva, Luís R.; Andrade, Paula B.; Valentão, Patrícia; Silva, Branca M.; Pereira, J.A.; Pinho, P. Guedes deFicus carica L. is one of the earliest cultivated fruit trees, having an important consumption in Mediterranean countries. In this work, the volatile compound profiles of two characteristic Portuguese white varieties (‘‘Pingo de Mel” and ‘‘Branca Tradicional”) was determined by HS-SPME and GC/FID. Leaves, pulps and peels, submitted to freezing and lyophilisation treatments, were analysed. The two varieties presented a similar profile composed of eight volatile compounds: acetaldehyde, ethyl acetate, methanol, ethanol, hexanal, limonene, (E)-2-hexenal and octanal. The total volatile content was different among the vegetal materials, following the order leaves > peels > pulps. Methanol and ethanol are the major compounds in all samples. The developed procedure revealed to be rapid, sensitive, reproducible and accurate. The detection limit values were low, and the method precise. The recovery values for acetaldehyde, ethyl acetate, methanol and ethanol were generally high, suggesting that it will be most suitable for compounds with low molecular weight. Due to its rapidity and low cost, this technique can be useful in the quality control of fig fruit and leaves.
- Development and evaluation of an HPLC/DAD method for the analysis of phenolic compounds from olive fruitsPublication . Vinha, Ana F.; Silva, Branca M.; Andrade, Paula B.; Seabra, Rosa M.; Pereira, J.A.; Oliveira, BeatrizA 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 (Cobrançosa, 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 (25.0 × 0.46 cm; 5 μm, 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 μg/mL and the method was precise. As a general 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 . Vinha, Ana F.; Andrade, Paula B.; Silva, Branca M.; Pereira, J.A.; Valentão, Patrícia; Seabra, Rosa M.; Oliveira, Beatriz
- Dracaena draco L. fruit: phytochemical and antioxidant activity assessmentPublication . Silva, Branca M.; Santos, Rui P.; Mendes, Lídia S.; Pinho, P. Guedes de; Valentão, Patrícia; Andrade, Paula B.; Pereira, J.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.
- Effect of the conservation procedure on the contents of phenolic compounds and organic acids in Chanterelle (Cantharellus cibarius) MushroomPublication . Valentão, Patrícia; Andrade, Paula B.; Rangel, Joana; Ribeiro, Bárbara; Silva, Branca M.; Baptista, Paula; Seabra, Rosa M.To check the influence of the conservation procedure in the chemical composition of chanterelle mushroom, phenolic compounds and organic acids of samples preserved under four different conditions (drying, freezing, conservation in olive oil and in vinegar) were determined. Phenolics and organic acids were analyzed by HPLC-DAD and HPLC-UV, respectively. The results showed that chanterelle is characterized by the presence of six phenolic compounds (3-, 4-, and 5-O-caffeoylquinic acid, caffeic acid, p-coumaric acid, and rutin) and five organic acids (citric, ascorbic, malic, shikimic, and fumaric acids). Samples preserved in olive oil also exhibited hydroxytyrosol, tyrosol, luteolin, and apigenin, whereas conservation in vinegar led to the detection of hydroxytyrosol, tyrosol, and tartaric acid in the analyzed samples. The conservation procedures to which chanterelle samples were subjected seem to affect the qualitative and quantitative phenolics and organic acids profiles.
- 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, J.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 2,20-diphenyl-1-picrylhydrazyl (DPPH) and to inhibit the 2,20-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 lg/ml) but significantly lower than that presented by green tea extract (EC50 mean value of 12.7 ± 0.1 lg/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 lg/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.
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