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Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae
Guedes, A. Catarina; Gião, Maria S.; Seabra, Rui; Ferreira, António César Silva; Tamagnini, Paula; Moradas-Ferreira, Pedro; Malcata, F. XavierA growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae) and 23 species of (eukaryotic) microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-s...
Plant aqueous extracts: Antioxidant capacity via haemolysis and bacteriophage
Gião, Maria S.; Leitão, Isabel; Pereira, Ana; Borges, André B.; Guedes, Catarina J.; Fernandes, João C.; Belo, Luís; Santos-Silva, Alice; Hogg, Tim A.The bacteriophage P22/Salmonella Typhimurium system, as well as human erythrocytes have been used to assay for protection, against forced oxidation caused by hydrogen peroxide, brought about by several aqueous extracts of selected adventitious plants grown in Portugal. This study proved, for the first time, that the aforementioned bacteriophage-based system is a suitable method to assess the antioxidant activit...
Antioxidant activity of chitooligosaccharides upon two biological systems: Eryt...
Fernandes, João C.; Eaton, Peter; Nascimento, Henrique; Gião, Maria S.; Ramos, Óscar S.; Belo, Luís; Santos-Silva, Alice; Pintado, Manuela E.Most of the reports to date on the antioxidant capacity of chitosans and chitooligosaccharides (COS) are based on strictly chemical methods. When studying antioxidants with potential in vivo applications, the method used to evaluate the antioxidant activity should be representative of the conditions in which the antioxidant might have a protective effect. In this work we evaluate the antioxidant activity of two...
Effect of particle size upon the extent of extraction of antioxidant power from...
Gião, Maria S.; Pereira, Cláudia I.; Fonseca, Susana C.; Pintado, Manuela E.; Malcata, F. XavierThe dependence of the extent of aqueous extraction of antioxidant compounds on particle size and contact time was studied for three important medicinal plants, that are commonly used in infusions: agrimony, sage and savoury. The effect of extraction time was dependent on the plant considered; however, ca. 5 min can be taken as the minimum period required to assure an acceptable degree of extraction of those com...
Protection of deoxyribose and DNA from degradation by using aqueous extracts of...
Gião, Maria S.; González-Sanjose, M. L.; Muñiz, Pilar; Rivero-Pérez, M. D.; Kosinska, Monika; Pintado, Manuela E.; Malcata, F. XavierBACKGROUND: Aqueous extracts of 48 herbal plants were obtained via alternative extraction protocols, and were assayed for their capacity to protect deoxyribose and DNA itself from degradation (or, conversely, for their capacity to promote DNA degradation), using electrophoresis as analytical tool. RESULTS: For a given (constant) volume of extract, deoxyribose protection ranged from 14.13 ± 1.35% (mean ± SD) in...
Antioxidant activity of sugar molasses, including protective effect against DNA...
Guimarães, Carla M.; Gião, Maria S.; Martinez, Sidónia S.; Pintado, Ana I.; Pintado, Manuela E.; Bento, Luís S.; Malcata, F. XavierExtracts were obtained from molasses, a byproduct of the sugar industry, via a number of chromatographic steps. Their antioxidant capacity was studied, including the inhibitory effect upon DNA oxidative damage;the phenolic compound profile there of was ascertained as well. Two extracts exhibited significant antioxidant features, expressed by their capacity to decolorize ABTS radical cation and to scavenge hydro...
Infusions of Portuguese medicinal plants: dependence of final antioxidant capac...
Gião, Maria S.; González-Sanjosé, Maria L.; Rivero-Pére, Maria D.; Pereira, Cláudia I.; Pintado, Manuela E.; Malcata, F. XavierBACKGROUND: Aqueous extracts of most medicinal plants traditionally employed in Portugal (at the ratio of 1 g plant: 110mL water) have been assayed for total antioxidant capacity and phenol content, in order to elucidate their claimed medicinal features. RESULTS: The antioxidant activity was assessed by theABTS•+ method; the ascorbic acid equivalent values ranged from 1.4280 ± 0.1261 g L−1 for avocado (Persea a...
Incorporation and survival of probiotic bacteria in whey cheese matrices
Madureira, Ana R.; Gião, Maria S.; Pintado, Manuela E.; Gomes, Ana M. P.; Freitas, A. Cristina; Malcata, F. XavierThe viabilities of probiotic strains of Lactobacillus acidophilus, Lactobacillus paracasei, Bifidobacterium animalis, and Lactobacillus brevis were studied following incorporation in a whey cheese matrix. Experimental production of plain, as well as sugar-added or salt-added whey cheeses, was based on the traditional manufacture protocol of Requeijäo, a Portuguese whey cheese that essentially results from prote...
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