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Branca M. Silva

Bio: Branca M. Silva is an academic researcher from University of Beira Interior. The author has contributed to research in topics: DPPH & Oxidative stress. The author has an hindex of 39, co-authored 111 publications receiving 4600 citations. Previous affiliations of Branca M. Silva include University of Porto & Fernando Pessoa University.


Papers
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TL;DR: The evaluation of the antioxidant activity of methanolic extracts showed that peel extract was the one presenting the highest antioxidant capacity, which seems to indicate that the phenolic fraction gives a higher contribution for the antioxidant potential of quince fruit and jam.
Abstract: To study the antioxidant activity of quince fruit (pulp, peel, and seed) and jam, methanolic extracts were prepared. Each extract was fractionated into a phenolic fraction and an organic acid fraction and was analyzed by high-performance liquid chromatography (HPLC)/diode array detection and HPLC/UV, respectively. Antiradical activities of the extracts and fractions were evaluated by a microassay using 1,1'-diphenyl-2-picrylhydrazyl. The phenolic fraction always exhibited a stronger antioxidant activity than the whole methanolic extract. Organic acid extracts were always the weakest in terms of antiradical activity, which seems to indicate that the phenolic fraction gives a higher contribution for the antioxidant potential of quince fruit and jam. The evaluation of the antioxidant activity of methanolic extracts showed that peel extract was the one presenting the highest antioxidant capacity. The IC50 values of quince pulp, peel, and jam extracts were correlated with the caffeoylquinic acids total content. Among the phenolic fractions, the seed extract was the one that exhibited the strongest antioxidant activity. The IC50 values of quince pulp, peel, and jam phenolic extracts were strongly correlated with caffeoylquinic acids and phenolics total contents. For organic acid fractions, the peel extract was the one that had the strongest antiradical activity. The IC50 values of quince pulp, peel, and jam organic acid fractions were correlated with the ascorbic acid and citric acid contents.

332 citations

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TL;DR: In this paper, the phenolic compounds present in 29 samples of olive fruits were analysed by reversed-phase HPLC/DAD and/or HPLC-DAD/ESI-MS/MS.

313 citations

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TL;DR: Ion trap HPLC-PAD-ESI/MS/MS has been used to study C-glycosyl flavones in quince seeds and deductions were made about the nature of the sugar units and the positions of C- Glycosylation.
Abstract: Ion trap HPLC-PAD-ESI/MS/MS has been used to study C-glycosyl flavones in quince seeds. Comparative analysis of the ions [(M-H)-60]-, [(M-H)-90]- and [(M-H)-120]- from 6-C- and 8-C-glycosyl flavone isomers, together with their respective retention times, allowed deductions to be made about the nature of the sugar units and the positions of C-glycosylation. Vicenin-2 (6,8-di-C-glucosyl apigenin), lucenin-2 (6,8-di-C-glucosyl luteolin), stellarin-2 (6,8-di-C-glucosyl chrysoeriol), isoschaftoside (6-C-arabinosyl-8-C-glucosyl apigenin), schaftoside (6-C-glucosyl-8-C-arabinosyl apigenin), 6-C-pentosyl-8-C-glucosyl chrysoeriol and 6-C-glucosyl-8-C-pentosyl chrysoeriol were identified in quince seed.

275 citations

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TL;DR: The results obtained herein strongly indicate that walnut tree constitute an excellent source of effective natural antioxidants and chemopreventive agents.

268 citations

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TL;DR: This is the first study comparing the chemical composition and biological potential of F. carica pulps, peels and leaves and leaves' organic acids profile presented oxalic, citric, malic, quinic, shikimic and fumaric acids.

228 citations


Cited by
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TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

Journal Article
Fumio Tajima1
30 Oct 1989-Genomics
TL;DR: It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.

11,521 citations

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TL;DR: A review of phenolic and polyphenolic compounds can be found in this article, which summarizes both the synthetic and natural phenolic antioxidants, emphasizing their mode of action, health effects, degradation products and toxicology.

1,800 citations

Journal ArticleDOI
TL;DR: This overview provides a cursory account of the source, extraction and analysis of phenolics in fruits, vegetables and cereals.

1,251 citations

Journal Article
TL;DR: In this article, the authors examined the safety and possible efficacy of consuming the equivalent of > or =10 cups (> or =2.4 L) of green tea per day.

758 citations