Browsing by Author "Figueiredo, A. Cristina"
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- Antioxidant, Anti-inflammatory and Anti-hyperglycaemic Activities of Essential Oils from Thymbra capitata, Thymus albicans, Thymus caespititius, Thymus carnosus, Thymus lotocephalus and Thymus mastichina from PortugalPublication . S, Azza; EL-GEUNDOUZ, Soukaina; Miguel, Maria; Antunes, Maria Dulce; Faleiro, Maria Leonor; Correia, A. Isabel; Figueiredo, A. CristinaThe in vitro antioxidant, anti-inflammatory, anti-hyperglycaemic, and anti-acetylcholinesterase activities of the essential oils (EOs) isolated from six Lamiaceae species (Thymbra capitata, Thymus albicans, Th. caespititius, Th. carnosus, Th. lotocephalus and Th. mastichina) grown in Portugal, were evaluated. Th. caespititius and T. capitata carvacrol/thymol-rich EOs showed the best capacity for preventing lipid peroxidation, and scavenging the 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and peroxyl free radicals, as well as for inhibiting lipoxygenase and alpha-amylase. However, Th. caespititius and Th. lotocephalus 1,8-cineole and linalool rich EOs were the best inhibitors of alpha-glucosidase. T. capitata, Th. lotocephalus and Th. albicans EOs were the most active for inhibiting acetylcholinesterase. Th. caespititius and Th. mastichina EOs were the main scavengers of nitric oxide (NO) radicals. The comparison between the present data with a survey of the existing literature on the in vitro biological activities of the essential oils isolated from the same species from Portuguese origin, using other methodologies, showed some differences. For instance the use of two oxidizable substrates (egg yolk and lecithin liposomes) led to distinct results mainly for those samples with relatively low activity. In addition, the EOs capacity for scavenging peroxyl radicals was also influenced by the presence of cyclodextrins, as a synergism seemed to occur between EOs and those carbohydrates.
- Characterization of volatiles from Moroccan propolis samplesPublication . EL-GEUNDOUZ, Soukaina; Lyoussi, Badiaa; Miguel, Maria Graca; Figueiredo, A. CristinaThe volatiles from 24 propolis samples collected from different geographical locations in Morocco were evaluated. Propolis volatiles isolated by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Cluster analysis based on propolis samples’ volatile chemical composition defined two main uncorrelated clusters. Cluster I, with 23 of the 24 samples analyzed, included three subgroups, Ia, Ib1 and Ib2, dominated by βeudesmol (11–30%), cedrol (7–40%) and n-tricosane (6–34%), respectively. Cluster II included just one sample, with ar-curcumene (32%) as the main component. The results obtained contributed to increase the knowledge on the chemical composition and variability of Moroccan propolis samples. The volatile profile of these samples was distinct from those of Algeria, Canary Islands and Ethiopia, the sole African propolis volatiles studied so far.
- Chemical characterization and biological properties of royal jelly samples from the mediterranean areaPublication . EL-GEUNDOUZ, Soukaina; Machado, Alexandra M.; AAZZA, Smail; Lyoussi, Badiaa; Miguel, Maria; Mateus, Maria; Figueiredo, A. CristinaRoyal jelly (RJ) is a bee product that has high nutritional value and is beneficial for the human health, earning importance as a functional food. Thus, the characterization of its main biological properties is with high importance. In this work, 6 RJ samples obtained in Morocco, Portugal, and Spain were evaluated in terms of total phenol and flavone/flavonol contents; total protein; 10-hydroxy-2-decenoic acid (10-HDA); volatiles composition; antioxidant and anti-inflammatory properties; and inhibition of tyrosinase, xanthine oxidase (XO), and acetylcholinesterase (AChE) activities. Total phenolic content ranged from 3 to 9 mg gallic acid equivalent/g RJ, and flavone/flavonol content from 0.1 to 0.5 mg quercetin equivalent/g RJ. 10-Hydroxy-2-decenoic acid content varied from 0.9% to 1.2% and total protein from 5.5% to 29.7%. Gas chromatography-flame ionization detector and gas chromatography-mass spectrometry analysis showed RJ volatiles dominated by linolenic acid, 2-decenoic acid, and octanoic acid in variable amounts. The antioxidant activity was monitored through nitric oxide (NO) scavenging activity and hydrogen peroxide (H2O2) scavenging capacity, where the IC50 ranged from 2.3 to 3.4 and 0.2 to 1.5 mg/mL, respectively. Anti-AChE activity IC50 ranged from 0.7 to 4.6 mg/mL, while XO inhibition IC50 ranged from 3.3 to 11.9 mg/mL. The results showed that phenols and flavonoids highly contributed to the RJ biological properties in contrast to 10-HDA and proteins.
- Composition, chemical variability and effect of distillation time on leaf and fruits essential oils of Myrtus communis from north western AlgeriaPublication . Hennia, Aicha; Miguel, Maria Graça; Brada, Moussa; Nemmiche, S.; Figueiredo, A. CristinaThe chemical variability of the essential oils isolated from Myrtus communis L. leaves and fruits collected from the North western Algeria was evaluated along with a hydrodistillation timecourse study of the essential oil main components. M. communis essential oils were isolated by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). The essential oils yields ranged between 0.28% and 0.77% (w/d.w.). Although in variable ranges the leaf (L) and the fruits (F) essential oils were characterized by the dominance of the same compounds: α-pinene (23–49% and 21–43% for L and F, respectively), 1,8-cineole (10–24% and 5-31% for L and F, respectively); limonene (11–30% and 9–35% for L and F, respectively); and linalool (2–32% and 1–7% for L and F, respectively). For the first time, Algerian linalool-rich myrtle essential oils (>30%) are described. Higher relative amounts of α-pinene, 1,8-cineole, limonene and linalool can be obtained with shorter distillation times.
- Mineral and volatile composition of agua-mel from PortugalPublication . Miguel, Maria Graça; AAZZA, Smail; Antunes, Maria Dulce; Faleiro, Maria Leonor; Barroso, José G.; Pedro, Luis G.; Figueiredo, A. CristinaAgua-mel (honey-water) is a typical honey-based product produced by the Portuguese beekeepers, particularly in southern Portugal. Agua-mel was characterized by mineral content and volatiles contents. Mineral content evaluation was performed based on a random sampling of 14 samples from a total of 16 samples provided by local producers. Mineral content showed that potassium predominated in agua-mel samples (1270-4105 mg/kg). The concentration of aluminium in one sample was tenfold higher (5.8 mg/kg) than in the remaining samples (0.3-0.6 mg/kg). Agua-mel volatiles were isolated by hydrodistillation and analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) from a subset of eight samples. Cluster analysis showed two poorly correlated clusters (S (corr) < 0.3). Cluster I only sample was dominated by trans-beta-ocimene (19 %), gamma-terpinene (15 %) and 2-furfural (9 %). Cluster II that included the remaining seven samples showed two moderately correlated subclusters (S (corr) < 0.5). The six samples with high correlation from subcluster IIa were dominated by 2-furfural (18-41 %) and benzene acetaldehyde (12-39 %). n-Nonadecane (14 %), n-heneicosane and 2-furfural (both 13 %) were the main components of subcluster IIb sample. Although the presence of some volatile compounds can help in the correlation between agua-mel and honey botanical source, the final product varies largely according to the preparation process even for the same producer, in different years. Agua-mel detailed characterization may assist in bringing added value to this typical Portuguese honey-based product.
- β-Cyclodextrin inclusion complexes of combined Moroccan Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium volatile oil: production optimization and release kinetics in food modelsPublication . El Kharraf, Sara; Farah, Abdellah; EL-GUENDOUZ, Soukaina; Lourenço, João P.; Rosa Da Costa, Ana; El Hadrami, El Mestafa; Machado, Alexandra M.; Tavares, Cláudia S.; Figueiredo, A. Cristina; Miguel, MGA combined volatile oil (VO) was extracted from Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium by simultaneous hydro- and steam-distillation, and encapsulated in beta-cyclodextrin by co-precipitation. Response surface methodology (RSM) was used to optimize microencapsulation conditions. The variable recovered powder, VO retention degree, and inclusion efficiency were investigated based on two factors: solid-to-liquid and liquid-to-liquid (ethanol/water) ratios. The responses were influenced by the concentration of ethanol in the reaction mixture and the amount of VO used. VO release from the inclusion complexes was investigated in 10% ethanol and in 3% acetic acid. The obtained data were fitted to the first-order Korsmeyer-Peppas, Higuchi, and Peppas-Sahlin models. The Higuchi model gave the fittest approach for the VO release profile in both cases, showing that the release mechanism was controlled by Fickian diffusion.