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- Effect of storage time at low temperature on the volatile compound composition of Sevillana and Maravilla raspberriesPublication . Morales, M. L.; Callejon, R. M.; Ubeda, C.; Guerreiro, Adriana; Gago, Custódia; Miguel, Maria Graça; Antunes, Maria DulceIn this study, the effect of storage time at low temperature on volatile compounds in two cultivars of raspberry, Rubus idaeus L. cv. Sevillana and Maravilla, was determined. A total of 28 compounds were identified in both cultivars and showed quantitative differences between the cultivars. The Sevillana cultivar was richer in volatile compounds than the Maravilla cultivar. beta-Ionone had the highest concentration in both cultivars. We observed opposing trends in the volatile compound composition for the cultivars during storage at low temperature, in which 'Sevillana' lost compounds and 'Maravilla' was enriched. Therefore, storage at low temperature causes important changes in the volatile compound profile of raspberry, particularly the Sevillana cultivar, with significant decreases in C-13-norisoprenoids and increases in terpenes. These changes are most likely responsible for the aromatic differences between the cultivars because of the presence of terpenes in 'Sevillana' and C-13-norisoprenoids in 'Maravilla'. (C) 2014 Elsevier B.V. All rights reserved.
- Pomegranate (Punica granatum L.): A medicinal plant with myriad biological properties - A short reviewPublication . Miguel, Maria Graça; Neves, M. A.; Antunes, Maria DulceThe pomegranate, Punica granatum L., which can be found throughout the Mediterranean region, in Southeast Asia, California and Arizona in USA was in ancient times referred as possessing powers of fertility, abundance and good luck (fruit). The biological properties of extracts (antimicrobial, antioxidant, anticancer, anti-inflammatory, among other properties) obtained from several parts of pomegranate is reported in the present work. Due to such properties, the extracts have been used in therapeutics, such as in the prevention of infection, inflammation, cancer, among other applications. However, other aspects are also referred in the present work such as the good practices of culture and fruit preservation, search of new compounds, selection of cultivars through biotechnological techniques for obtaining juice or fruits ready to eat. Such compilation of information was based on the search in the ISI Web of Knowledge (Thomson Reuters) from 2009 up to the beginning of October 2010.
- Bioproducts from forest biomass II. Bioactive compounds from the steam-distillation by-products of Cupressus lusitanica Mill. and Cistus ladanifer L. wastesPublication . Tavares, Claudia S.; Martins, Alice; G, Miguel; Carvalheiro, Florbela; Duarte, Luis C.; Gameiro, Jose A.; Cristina Figueiredo, A.; Roseiro, Luisa B.Obtaining essential oils and hydrolates from underutilized biomass is an economic and sustainable way for production of these high added-value bioproducts. However, this process still generates large amounts of residues as the by-products obtained during distillation, which can be a concern for the environment, but also adequate substrates for other applications. Considering this fact, the waste distilled by-products remaining after steam distillation of underutilized biomass from Cupressus lusitanica and Cistus ladanifer, were evaluated as a natural source of other high value products with biological activities, namely, phenolic compounds. Thus, the remaining extracted solid residues (ESRs) were characterized and subject to further treatments by ultrasound-assisted extraction (UAE) with ethanol and 70 % acetone, in order to prepare phenolic-rich extracts thereof: ESRs (EtOH) and ESRs(70 % Ace). Together with the distiller condensation waters (DCWs), these extracts were characterized for their phenolic content (total phenols, tannins and flavonoids). Their antioxidant activity was also evaluated by different methodologies. the phenolic profile of DCWs, ESRs(EtOH) and ESRs(70 % Ace) from both waste species was obtained by capillary zone electrophoresis (CZE) and phenolic compounds were tentatively identified. Results obtained for C. lusitanica biomass are here disclosed for the first time. Generally, all samples revealed to be rich in phenolic compounds, being C. ladanifer biomass the one with higher phenolic content. DCWs presented values of 140 mgGAE/g for C. lusitanica and 210 mg GAE/g for C. ladanifer, from which ca. 60 % were tannins. Extracts obtained with 70 % acetone were the ones with the highest results, except for the antioxidant activity by xanthine oxidase and superoxide inhibition, which was higher in DCWs. Catechins were the major compounds found for both species, but gallocatechins and gallic acid were only identified in C. ladanifer. Hydroxycinnamic acid derivatives and salicylic acid were also identified in C. ladanifer, partly justifying the anti-inflammatory effect referred for this species.
- Stability of fried olive and sunflower oils enriched with thyrnbra capitata essential oilPublication . Miguel, Maria; Antunes, Maria Dulce; Rohaim, Abdulrahman; Figueired, Ana Cristina; Pedro, Luis G.; Barroso, Jose G.The stability of olive and sunflower oils for domestic uses after frying cow steak or only heating were evaluated in the presence or absence of the carvacrol-rich essential oil of Thymbra capitata. The treatments consisted of sunflower and olive oils either enriched with 200 mg/l of T capitata oil or without it, heating at 180 degrees C for 20 min, or frying 100 g cow steak at the same temperature and for the same period of time. In all assays, acid, peroxide, and p-anisidine values were followed over time. The fatty acid profile was estimated before heating or frying as well as at the end of the experiment. The results showed that the type of fat as well as the type of treatment (frying or heating) was determinant for the acid, peroxide, and p-anisidine values found. The presence of the essential oil also demonstrated to affect those values depending on the type of the oil as well as on the type of the treatment (frying or heating). In contrast, the fatty acid profile did not change greatly.
- Propolis volatiles characterisation from acaricide-treated and -untreated beehives maintained at Algarve (Portugal)Publication . Miguel, Maria Graça; Nunes, S.; Cruz, C.; Duarte, J.; Antunes, Maria Dulce; Cavaco, A. M.; Mendes, M. D.; Lima, A. S.; Pedro, L. G.; Barroso, J. G.; Figueiredo, A. C.The variability of the volatile profile of 70 propolis samples from acaricide-treated and -untreated beehives maintained at Algarve (Portugal) was evaluated. Propolis samples were collected in three regions of Algarve at three different periods. Cluster analysis based on the propolis volatiles' chemical composition defined two main clusters, not related to the time of year, collection site, altitude, temperature or humidity ranges, and was based mainly on the relative amounts of viridiflorol, n-tricosane and n-nonadecane for cluster I. Cluster II was mainly characterised by the high thymol content, followed by viridiflorol, n-tricosane and n-nonadecane. The presence of higher thymol levels in propolis samples from cluster II may reflect the long use of an acaricide with thymol as main active ingredient. All samples showed an intense rock-rose aroma supported by the presence of characteristic Cistus and labdanum oil volatile components. Given the nowadays frequent propolis household use, volatiles thorough characterisation may assist in its quality assessment.
- Antioxidant and anti-lipoxygenase activities of extracts from different parts of Lavatera cretica L. grown in Algarve (Portugal)Publication . Ben Nasr, S.; S, Azza; Mnif, W.; Miguel, Maria GraçaBackground: Lavatera cretica L. was used in folk medicine as anti-inflammatory among other applications. As inflammation is many times associated with oxidative processes, the aim of the present work was to evaluate the ability of aqueous extracts obtained from different parts of L. cretica to prevent oxidation or inflammation using several methods in vitro. Materials and Methods: The capacity of samples for preventing lipid peroxidation, scavenging free radicals, chelating metal ions, reducing power, and inhibiting lipoxygenase activity was investigated. This last assay also permits to evaluate the anti-inflammatory activity. The quantification of total phenols was performed using Folin-Chiocalteu reagent. Results: The highest concentrations of total polyphenols and flavonoids were found in the leaf extract (254.62 6.50 mg gallic acid equivalent/gram; dry weight). Leaf and flower extracts were the most active for scavenging 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radicals [Inhibition concentration (IC 50 = 2.88 0.54 and IC50 = 4.37 0.54 g/mL, respectively)], and leaf extract was also the best for scavenging hydroxyl radicals (IC 50 = 0.81 0.05 g/mL). Bract plus sepal extract possessed the best capacity for preventing lipid peroxidation when lecithin liposome was the lipid substrate (IC 50 = 0.19 0.03 g/mL) and scavenging superoxide anion radicals (IC 50 = 1.13 0.48 g/mL). Leaf and flower extracts were the best lipoxygenase inhibitors (IC 50 = 0.013 0.0034 g/mL in both extracts). Conclusions: L. cretica extracts were able to scavenge free radicals, inhibit lipid peroxidation and lipoxygenase activity. With these attributes, this plant can have an important role in the treatment of neurodegenerative disorders.
- Aromatic plants, spices and volatiles in food and beveragesPublication . Figueiredo, A. C.; Miguel, Maria GraçaThe use of spices, common nowadays, was once a sign of high position, luxury and wealth. The value of food ingredients is thus determined by the time in which one lives, that is, it is a product of fashion, since they are always used in a social context. Many plants used as spices enjoyed fame and undeniable importance in the past but their reign was more or less ephemeral, as they were rejected in favour of others for food seasoning, or simply upstaged and/or used for other purposes.
- Anti-oxidant, Anti-inflammatory and Anti-proliferative Activities of Moroccan Commercial Essential OilsPublication . S, Azza; Lyoussi, B.; Megias, C.; Cortes Giraldo, I.; Vioque, J.; Figueiredo, A. C.; Miguel, Maria GraçaEssential oils (EO) possess antimicrobial, anti-inflammatory, insect repellent, anti-cancer, and antioxidant properties, among others. In the present work, the antioxidant, anti-inflammatory and anti-proliferative activities of Moroccan commercial EOs (Citrus aurantium, C. union, Cupressus sempervirens, Eucalyptus globulus, Foeniculum vulgare and Thymus vulgaris) were evaluated and compared with their main constituents. T. vulgaris EO showed the best free radicals scavenging capacity. This EO was also the most effective against lipid peroxidation along with C. limon and F. vulgare EOs. C. sempervirens EO was the most effective in scavenging NO free radicals, whereas C. limon EO showed the best chelating power. Not all of the major compounds of the EO were responsible for the whole activity of the EOs. T. vulgaris EO showed the best anti-proliferative activity against THP-1 cells in contrast to that of F. vulgare. The antioxidant and anti-inflammatory activities of the EOs were plant species dependent and not always attributable to the EOs main components. Nevertheless, the EOs anti-proliferative activities were more related to their main components, as with T. vulgaris, C. limon, E. globulus and C. sempervirens.
- Chemical variability of the essential oils from Rosa canina L. and Rosa sempervirens L. flowers collected at TunisiaPublication . Ghazghazi, H.; Miguel, Maria Graça; Weslati, M.; Hasnaoui, B.; Sebei, H.; Barroso, J. G.; Pedro, L. G.; Figueiredo, A. C.The chemical variability of the essential oils of Rosa canina L. and R. sempervirens L. flowers collected at seven localities from northern Tunisia was investigated by gas chromatography (GC) and GC-mass spectrometry (GC-MS). The essential oils yields ranged between 0.7% and 1.4% (v/f.w.) for R. canina and R. sempervirens, respectively. Forty-one components were identified in R. canina and twenty-six in R. sempervirens oils. Rosa canina essential oil, from plants collected at Ain Draham, was dominated by beta-caryophyllene (32%) and geraniol (21%), whereas in the oils from plants collected at Boussalem n-heneicosane (29%), p-cymene (12%) and beta-caryophyllene (11%) predominated. However, the oil isolated from the samples collected at Fernana was dominated by 2,4,6-trimethyl-octane (9%), n-undecane (8%) and geraniol (8%). p-Cymene (14%), limonene (11%) and gamma-terpinene (11%) were the main components of the oil isolated from Feija samples. Rosa sempervirens oils, from plants collected at Ain Draham and Fernana, were characterized by a high 2-phenylethyl alcohol content (29% and 93%, respectively). The major components of the oil isolated from Tabarka samples were p-cymene (16%) and gamma-terpinene (12%). Cluster analysis of the essential oils composition from the studied populations, confirmed the major chemical variability.
- Physicochemical Characterization and Antioxidant Activity of Commercial Portuguese HoneysPublication . AAZZA, Smail; Lyoussi, B.; Antunes, Maria Dulce; Miguel, Maria GraçaThe present study evaluated the physicochemical characteristics and antioxidant activity of 13 commercial honeys from diverse floral origin, produced in Portugal. The values of electrical conductivity of cardoon and pennyroyal honeys were superior to the maximum limits defined by European legislation. Citrus, strawberry tree, and 1 sample of lavender honeys had values of diastase activity below those determined by European legislation. Strawberry tree, pennyroyal, and cardoon honeys had the highest amounts of potassium that coincided with the highest electrical conductivity. Strawberry tree honey was the most effective as antioxidant along with cardoon and heather honeys. This ability was strongly correlated with the amounts of phenols and flavonoids and not with the levels of vitamin C or proline.