EMBEDDED SYSTEMS FOR ELLIPTIC CURVE

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Targeting excessive free radicals with peels and juices of citrus fruits: grapefruit, lemon, lime and orange

Publication . Guimarães, Rafaela; Barros, Lillian; Barreira, João C.M.; Sousa, Maria João; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.

A comparative study between the antioxidant properties of peel (flavedo and albedo) and juice of some commercially grown citrus fruit (Rutaceae), grapefruit (Citrus paradisi), lemon (Citrus limon), lime (Citrus aurantiifolia) and sweet orange (Citrus sinensis) was performed. Different in vitro assays were applied to the volatile and polar fractions of peels and to crude and polar fraction of juices: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, reducing power and inhibition of lipid peroxidation using b-carotene–linoleate model system in liposomes and thiobarbituric acid reactive substances (TBARS) assay in brain homogenates. Reducing sugars and phenolics were the main antioxidant compounds found in all the extracts. Peels polar fractions revealed the highest contents in phenolics, flavonoids, ascorbic acid, carotenoids and reducing sugars, which certainly contribute to the highest antioxidant potential found in these fractions. Peels volatile fractions were clearly separated using discriminant analysis, which is in agreement with their lowest antioxidant potential.

2010Journal article

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Systematic evaluation of the antioxidant potential of different parts of Foeniculum vulgare Mill. from Portugal

Publication . Barros, Lillian; Heleno, Sandrina A.; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.

Fennel (Foeniculum vulgare Mill.) is a widespread perennial umbeliferous (Apiaceae) herb, traditionally used for medicinal purposes and human consumption. It is highly recommended for diabetes, bronchitis and chronic coughs, and for the treatment of kidney stones; some of those chronic diseases are related to the production of radical species involved in the oxidative stress. Therefore, the antioxidant potential of this herb might explain some of their empirical uses in folk medicine. This is the first time that a systematic study on different parts of fennel is performed, in order to understand differences in the antioxidant potential of shoots, leaves, steams, and inflorescences, particularly related to their composition in antioxidant compounds such as vitamins (ascorbic acid and tocopherols) and phenolics. The shoots seems to have the highest radical-scavenging activity and lipid peroxidation inhibition capacity (EC50 values < 1.4 mg/ml), which is in agreement with the highest content in phenolics (65.85 ± 0.74 mg/g) and ascorbic acid (570.89 ± 0.01 lg/g) found in this part. The shoots also revealed high concentration of tocopherols (34.54 ± 1.28 lg/g) and were the only part with flavonoids.

2009Journal article

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Cistus ladanifer as a source of phenolic compounds with antifungal activity

Publication . Barros, Lillian; Dueñas, Montserrat; Alves, Carlos Tiago; Silva, Sónia; Henriques, Mariana; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.

A screening of the antifungal potential of phenolic extract of Cistus ladanifer from Northeast Portugal, against Candida species was performed. The extract was characterized by HPLC-DAD-ESI/MS. Phenolic acids and derivatives, ellagic acid derivatives and flavonoids, such as catechins, flavonols and flavones, were found in the sample. The most abundant group was ellagic acid derivatives in which punicalagin gallate, a derivative of punicalagin attached to gallic acid, was found in highest amount. These compounds could be related to the strong inhibition of C. albicans, C. glabrata and C. parapsilosis growth. Moreover, the best antifungal activity was against C. glabrata, where the studied extract was able to cause at least 3 Log of reduction at concentrations below 50 µg/mL and a total growth inhibition at concentrations above 625 µg/mL.

2012Conference object

Open access

Avaliação da atividade antioxidante e análise cromatográfica de açúcar e tocoferóis em iogurtes com fruta: pêssego, ananás, ameixa e manga

Publication . Pereira, Eliana; Barros, Lillian; Ferreira, Isabel C.F.R.

Tem-se verificado, nos últimos tempos, um grande interesse na incorporação de aditivos naturais ao iogurte, incluindo vários frutos conhecidos como ótimas fontes de antocianinas. A finalidade desta inclusão tem como objetivo aumentar a atividade antioxidante e funcionalidade desses alimentos melhorando, desta forma, a proteção do consumidor contra patologias relacionadas com os radicais livres [1-3]. Neste trabalho, desenvolveu-se um estudo comparativo do potencial antioxidante de iogurtes com pedaços de manga, ananás, ameixa e pêssego. Os açúcares e os tocoferóis foram identificados e quantificados por cromatografia líquida de alta eficiência acoplada a deteção por índice de refração (HPLC-RI) e por HPLC-fluorescência, respetivamente. Fenóis e flavonóides foram determinados por meio de técnicas espectrofotométricas tendo-se avaliado, também, a atividade captadora de radicais DPPH (2,2-difenil-1-picril-hidrazilo), poder redutor e inibição da peroxidação lipídica. O estudo realizado revela que os açúcares presentes são a frutose, glucose, galactose, sacarose e lactose, encontrados em maior e menor quantidade nos iogurtes de manga e ameixa, respetivamente. Destaca-se ainda o facto do valor obtido para os açúcares totais ser idêntico ao indicado no rótulo. No que diz respeito aos tocoferóis, foram encontradas as isoformas α, γ e δ-tocoferol, realçando-se o iogurte de pêssego que apresentou maior teor da totalidade dos mesmos, assim como, com o menor valor de EC50 nos ensaios da atividade captadora de DPPH e inibição da peroxidação lipídica (20,67 e 37,22 mg/mL, respetivamente). A quantidade de fenóis variou entre 1,07 e 6,90 mg/g extrato, surgindo em maior abundância no iogurte de ananás. Assim, a adição de fruta ao iogurte para além de lhe alterar as características organoléticas, contribui com compostos antioxidantes que beneficiam o organismo no fortalecimento do sistema imunológico e combate a doenças relacionadas com o stresse oxidativo.

2012Conference object

Open access

Study and characterization of selected nutrients in wild mushrooms from Portugal by gas chromatography and high performance liquid chromatography

Publication . Heleno, Sandrina A.; Barros, Lillian; Sousa, Maria João; Martins, Anabela; Ferreira, Isabel C.F.R.

The present work aims at contributing to the documentation of the nutritional composition of wild mushrooms. Fatty acid and sugar profiles of 10 different Portuguese wild mushrooms were obtained by gas chromatography coupled to a flame ionization detector (GC/FID) and high performance liquid chromatography coupled to a refraction index detector (HPLC/RID), respectively, the latter methodology being then completely validated. The macronutrient profile in general revealed that the wild mushrooms were rich sources of protein (24.32–76.63 g/100 g) and carbohydrates (10.35–55.48 g/100 g), and had low amounts of fat (0.36–2.63 g/ 100 g). The highest energetic contribution was guaranteed by Hygrophoropsis aurantiaca. The analysis of fatty acid composition allowed the quantification of 25 fatty acids. Unsaturated fatty acids and, in particular, oleic and linoleic acids, were predominant (17–61% and 20–54%, respectively). In the analysis of free sugars, all the compounds were separated in a period of time of 10 min; the method used proved to be sensitive, reproducible and accurate. Arabinose (1.53–7.66 g/100 g), mannitol (0.38–18.41 g/100 g) and trehalose (0.21–18.66 g/ 100 g) were the most abundant sugars.

2009Journal article

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