Browsing by Author "Dias, Cristina Barrocas"
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- Comparative study of the antioxidant and enzyme inhibitory activities of two types of moroccan euphorbia entire honey and their phenolic extractsPublication . Boutoub, Oumaima; El-Guendouz, Soukaïna; Manhita, Ana; Dias, Cristina Barrocas; Estevinho, Leticia M.; Paula, Vanessa B.; Carlier, Jorge D.; Costa, Maria Clara; Rodrigues, Brígida; Raposo, Sara; Aazza, Smail; El Ghadraoui, Lahsen; Miguel, Maria da GraçaHoney is a natural food product very famous for its health benefits for being an important source of antioxidant and phenolic compounds. Euphorbia honeys obtained from different regions of Morocco were evaluated for their ability to inhibit acetylcholinesterase, lipoxygenase, tyrosinase and xanthine oxidase activities. Their antioxidant properties were evaluated using the: 2,2-diphenyl- 1-picrylhydrazyl (DPPH) radical-scavenging capacity, nitric oxide scavenging activity (NO) and scavenging ability of superoxide anion radical. Then, the phenolic extracts of the same entire honey samples were evaluated by liquid chromatography coupled to diode array detection and mass spectrometry (LC-DAD-MS) and tested for the biological activities previously evaluated on the entire honeys, in order to conduct a comparative study between both (honey and phenolic extracts). The chromatographic profiles for the studied Euphorbia honey extracts were different. Phenolic compounds gallic acid, 4-hydroxybenzoic acid and p-coumaric acid were detected in all samples, whereas kampferol was only present in two samples. Physicochemical parameters and total phenolic content were also determined. Entire honey that recorded the highest rate of phenols was sample M6 (E. resinifera) = 69.25 mg GAE/100 g. On the other hand, the phenolic extracts had better antioxidant and enzyme inhibitory activities than the entire honeys, regardless the monofloral honey type. In conclusion, the studied Euphorbia honeys may have a great potential as antioxidant, anti-inflammatory and anti-tyrosinase sources for pharmaceutical and cosmetic applications.
- Multivariate geostatistical analysis of stable isotopes in Portuguese varietal extra virgin olive oilsPublication . Jiménez-Morillo, Nicasio T.; Palma, Vera; Garcia, Raquel; Pereira, J.A.; Dias, Cristina Barrocas; Cabrita, Maria JoãoStable isotope contents of carbon, hydrogen and oxygen are known to reflect the geo-climatic conditions under which olives grown. This study aims to unravel the correlation between some of the main geographic variables and the isotopic composition of different Portuguese varietal extra virgin olive oil (EVOO) samples. Thus, the isotopic composition (δ13C, δ18O and δ2H) of 38 EVOO samples from 11 olive varieties from 2 Portuguese regions (Alentejo and Trás-os-Montes) was studied using an elemental analyzer coupled to an isotope ratio mass spectrometry. Multivariate analysis indicated that bulk δ13C, δ2H and δ18O values were enough to significantly (P < 0.05) predict altitude, latitude, longitude, temperature, rainfall, and sea distance. This work showed that the assessment of EVOO isotopic composition give information not only on the geographic origin, but also on the environmental conditions. To the best of our knowledge, this is the first report on bulk isotopic composition of Portuguese EVOOs.