Browsing by Author "Miguel, Maria Graca"
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- A review of plant metabolites with metal interaction capacity: a green approach for industrial applicationsPublication . Nobahar, Amir; Carlier, Jorge Dias; Miguel, Maria Graca; Costa, Maria ClaraRapid industrial development is responsible for severe problems related to environmental pollution. Many human and industrial activities require different metals and, as a result, great amounts of metals/heavy metals are discharged into the water and soil making them dangerous for both human and ecosystems and this is being aggravated by intensive demand and utilization. In addition, compounds with metal binding capacities are needed to be used for several purposes including in activities related to the removal and/or recovery of metals from effluents and soils, as metals' corrosion inhibitors, in the synthesis of metallic nanoparticles and as metal related pharmaceuticals, preferably a with minimum risks associated to the environment. Plants are able to synthesize an uncountable number of compounds with numerous functions, including compounds with metal binding capabilities. In fact, some of the plants' secondary metabolites can bind to various metals through different mechanisms, as such they are excellent sources of such compounds due to their high availability and vast diversity. In addition, the use of plant-based compounds is desirable from an environmental and economical point of view, thus being potential candidates for utilization in different industrial activities, replacing conventional physiochemical methods. This review focuses on the ability of some classes of compounds that can be found in relatively high concentrations in plants, having good metal binding capacities and thus with potential utilization in metal based industrial activities and that can be involved in the progressive development of new environmentally friendly strategies.
- AFLP assessment of the genetic relationships among 12 Thymus taxa occurring in PortugalPublication . da Silva, David V.; Duarte, Joao; Miguel, Maria Graca; Leitão, JoséThymus is a widely distributed genus in the Mediterranean region with several species endemic to the Iberian Peninsula. The genetic relationships among the 12 major Thymus taxa, T. albicans, T. caespititius, T. camphoratus, T. capitellatus, T. carnosus, T.lotocephalus, T. mastichina L. ssp. mastichina, T. pulegioides, T. villosus ssp. lusitanicus, T. villosus ssp. villosus, T. zygis ssp. sylvestris and T. zygis ssp. zygis, which occur in Portugal were assessed by AFLP (Amplified Fragment Length Polymorphisms) markers. A general agreement was found between the genetic relationships estimated by the AFLP markers and the accepted Thymus taxonomy based on morphological traits and essential oil content. The AFLP markers also supported suggestions for refinement of the taxonomy of this genus.
- Biological properties of latex, aqueous extracts and bee products of Euphorbia Officinarum L.: a short reviewPublication . Boutoub, Oumaima; Ghadraoui, Lahsen El; Miguel, Maria GracaEuphorbia officinarum L. is a Moroccan endemic plant known as “Tikiout” and “Daghmus” that can also be found in Mauritania, Western Sahara, and Algeria. In the present review, “Euphorbia officinarum”, “metabolites” “hemisynthesis” were the keywords used for the research in the Web search engine Google Scholar and in the database Web of Science. Triterpenes, phytosterols and ingol diterpenes were isolated and identified in the latex of Moroccan E. officinarum. More than sixty triterpenes were obtained by hemisynthesis from natural triterpenes. Some of these derivatives had insecticidal and antimicrobial activity (phytopathogenic bacteria). The total phenol content and the antioxidant and anti-α-glucosidase activities were dependent on the time and temperature of extractions and also on the plant solvent ratio. The antioxidant activity of monofloral honey of E. officinarum origin was attributed to the phenol fraction (this fraction, previously isolated from honey samples, had better activity than the entire honey).
- 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.
- Effect of essential oils on the release of TNF-α and CCL2 by LPS-Stimulated THP‑1 CellsPublication . Miguel, Maria Graca; Silva, Carina Isabel da; Farah, Luana; Castro Braga, Fernão; Figueiredo, Ana CristinaPlants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory tract or causing gastrointestinal or joint problems, among others. To support the traditional uses of plant extracts, EOs have been assessed for their alleged anti-inflammatory properties. However, the effect of EOs on the release of cytokines and chemokines has been much less reported. Considering their traditional use and commercial relevance in Portugal and Angola, this study evaluated the effect of EOs on the in vitro inhibition of the cytokine tumor necrosis factor-α (TNF-α) and the chemokine (C-C motif) ligand 2 (CCL2) by lipopolysaccharide (LPS)-stimulated human acute monocytic leukemia cells (THP-1 cells). Twenty EOs extracted from eighteen species from seven families, namely from Amaranthaceae (Dysphania ambrosioides), Apiaceae (Foeniculum vulgare), Asteraceae (Brachylaena huillensis, Solidago virgaurea), Euphorbiaceae (Spirostachys africana), Lamiaceae (Lavandula luisieri, Mentha cervina, Origanum majorana, Satureja montana, Thymbra capitata, Thymus mastichina, Thymus vulgaris, Thymus zygis subsp. zygis), Myrtaceae (Eucalyptus globulus subsp. maidenii, Eucalyptus radiata, Eucalyptus viminalis) and Pinaceae (Pinus pinaster) were assayed for the release of CCL2 and TNF-α by LPS-stimulated THP-1 cells. B. huillensis, S. africana, S. montana, Th. mastichina and Th. vulgaris EOs showed toxicity to THP-1 cells, at the lowest concentration tested (10 μg/mL), using the tetrazolium dye assay. The most active EOs in reducing TNF-α release by LPS-stimulated THP-1 cells were those of T. capitata (51% inhibition at 20 μg/mL) and L. luisieri (15-23% inhibition at 30 μg/mL and 78-83% inhibition at 90 μg/mL). L. luisieri EO induced a concentration-dependent inhibition of CCL2 release by LPS‑stimulated THP-1 cells (23%, 54% and 82% inhibition at 10, 30 and 90 μg/mL, respectively). These EOs are potentially useful in the management of inflammatory diseases mediated by CCL2 and TNF‑α, such as atherosclerosis and arthritis.
- Effect of essential oils on the release of TNF-α and CCL2 by LPS-stimulated THP‑1 CellsPublication . Miguel, Maria Graca; da Silva, Carina Isabel; Farah, Luana; Castro Braga, Fernão; Figueiredo, Ana CristinaPlants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory tract or causing gastrointestinal or joint problems, among others. To support the traditional uses of plant extracts, EOs have been assessed for their alleged anti-inflammatory properties. However, the effect of EOs on the release of cytokines and chemokines has been much less reported. Considering their traditional use and commercial relevance in Portugal and Angola, this study evaluated the effect of EOs on the in vitro inhibition of the cytokine tumor necrosis factor-α (TNF-α) and the chemokine (C-C motif) ligand 2 (CCL2) by lipopolysaccharide (LPS)-stimulated human acute monocytic leukemia cells (THP-1 cells). Twenty EOs extracted from eighteen species from seven families, namely from Amaranthaceae (Dysphania ambrosioides), Apiaceae (Foeniculum vulgare), Asteraceae (Brachylaena huillensis, Solidago virgaurea), Euphorbiaceae (Spirostachys africana), Lamiaceae (Lavandula luisieri, Mentha cervina, Origanum majorana, Satureja montana, Thymbra capitata, Thymus mastichina, Thymus vulgaris, Thymus zygis subsp. zygis), Myrtaceae (Eucalyptus globulus subsp. maidenii, Eucalyptus radiata, Eucalyptus viminalis) and Pinaceae (Pinus pinaster) were assayed for the release of CCL2 and TNF-α by LPS-stimulated THP-1 cells. B. huillensis, S. africana, S. montana, Th. mastichina and Th. vulgaris EOs showed toxicity to THP-1 cells, at the lowest concentration tested (10 μg/mL), using the tetrazolium dye assay. The most active EOs in reducing TNF-α release by LPS-stimulated THP-1 cells were those of T. capitata (51% inhibition at 20 μg/mL) and L. luisieri (15–23% inhibition at 30 μg/mL and 78–83% inhibition at 90 μg/mL). L. luisieri EO induced a concentration-dependent inhibition of CCL2 release by LPS‑stimulated THP-1 cells (23%, 54% and 82% inhibition at 10, 30 and 90 μg/mL, respectively). These EOs are potentially useful in the management of inflammatory diseases mediated by CCL2 and TNF‑α, such as atherosclerosis and arthritis.
- Growth, photosynthetic pigments, phenolic content and biological activities of Foeniculum vulgare Mill., Anethum graveolens L. and Pimpinella anisum L. (Apiaceae) in response to zincPublication . MAJDOUB, Nesrine; EL-GEUNDOUZ, Soukaina; Rezgui, Marwa; Carlier, Jorge; Clara Costa, Maria; Ben Kaab, Leila Bettaieb; Miguel, Maria GracaThe effect of zinc (Zn) on phenols, antioxidant activities (free radicals' scavenging activities, inhibition of lipid peroxidation, chelating activity and reducing power), and enzyme inhibition activities of acetylcholinesterase, lipoxygenase and tyrosinase of anise, dill and two cultivars of fennel [Latina" (F-L) and "Doux de Florence" (F-DF)] aqueous extracts was evaluated for the first time. At the same time, growth and photosynthetic pigment contents were also estimated. A significant decrease in all growth parameters, such as plant height, fresh and dry weights of aerial parts and roots was statistically proved in the presence of 2 mM Zn. An enhancement of Zn accumulation was observed, particularly in aerial part. Exposure to 2 mM Zn induced quantitative changes in the phenols of all tested extracts. In fennel extracts, a decrease of phenol content was observed when treated with Zn, whereas an increase was found in dill and anise extracts submitted to Zn treatment. All samples, either in the presence or absence of Zn, showed antioxidant activity, independent on the tested assay, with the exception of the cultivar F-DF (treated and non-treated), which was unable to scavenge NO radicals. Zn-treated dill and anise presented usually higher antioxidant activity. Concerning inhibitory activities against acetylcholinesterase, lipoxygenase and tyrosinase enzymes, both treated and non-treated F-DF did not inhibit acetylcholinesterase activity. Zinc-treated F-DF was also unable to inhibit lipoxygenase activity. The remaining species presented capacity for inhibiting those enzymes and tyrosinase as well, but their abilities varied in response to Zn excess.
- Impact of fifteen combinations of the main components of rosemary, lavender and citrus essential oils on in vitro biological activitiesPublication . Kharraf, Sara El; EL-GUENDOUZ, Soukaina; Farah, Abdellah; Mateus, Maria Da Conceição; Hadrami, El Mestafa El; Miguel, Maria GracaSince ancient times, essential oils or their volatiles have been used in food, health and aromatherapy. Essen-tial oils are complex mixtures constituted by dozens of compounds, which makes it difficult to attribute their biological properties to this or that compound or compound combinations. Moreover, the quantification of the volatiles is generally made through their relative percentage abundances. In the present study, the major volatiles isolated from Rosmarinus officinalis, Lavandula angustifolia, and Citrus aurantium essential oils extracted by simultaneous hydrodistillation-steam distillation were quantified through the external standard calibration method. Fifteen volatile mixtures were made using individual volatiles identified in the essential oils (EOs) to better find their role in the biological activities (antioxidant, anti-glucosidase, anti-inflammatory, anti-tyrosinase and anti-acetylcholinesterase activities). For almost mixtures assayed, the in vitro biological activities were generally poorer than those obtained for crude EOs, with the exception of the inhibitory effect on the a-glucosidase activity. In this case, 1,8-cineole and a-terpineol seem to have a positive role in inhibit-ing a-glucosidase activity, in contrast to camphor and borneol, which had the opposite action. Therefore there was a possible antagonist effect of both camphor and borneol in the volatile mixtures assayed on inhibiting the a-glucosidase activity. This approach also permitted us to conclude that there were several other factors not determined in the present work that were responsible for the activities found in the EOs,(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.
- Molecular cloning and functional characterization of a monoterpene synthase isolated from the aromatic wild shrub Thymus albicansPublication . Filipe, Alexandra; Cardoso, João; Miguel, Maria Graca; Anjos, Liliana; Trindade, Helena; Figueiredo, Ana Cristina; Barroso, Jose; Power, Deborah; Marques, N T.The essential oil of Thymus albicans Hoffmanns. & Link, a native shrub from the Iberian Peninsula, is mainly composed of monoterpenes. In this study, a 1,8-cineole synthase was isolated from the 1,8-cineole chemotype. A partial sequence that lacked the complete plastid transit peptide but contained an extended C-terminal when compared to other related terpene synthases was generated by PCR and Rapid Amplification of cDNA Ends (RACE). The predicted mature polypeptide was 593 amino acids in length and shared 78% and 77% sequence similarity with the homologue 1,8-cineole synthase from Rosmarinus officinalis and Salvia officinalis, respectively. The putative protein possessed the characteristic conserved motifs of plant monoterpene synthases including the RRx(8)W and DDxxD motifs and phylogenetic analysis indicated that the amplified 1,8-cineole synthase bears greater sequence similarity with other 1,8-cineole synthases from Lamiaceae family relative to the terpene synthases from the genus Thymus. Functional expression of the recombinant protein in Escherichia coli revealed that in the presence of geranyl diphosphate (GPP) 1,8-cineole was the major product but that its production was too low for robust quantification. Other minor conversion products included a-pinene, beta-pinene, sabinene and beta-myrcene suggesting the isolated 1,8-cineole synthase may be a multi-product enzyme. To our knowledge, this is the first report of a functionally characterized monoterpene synthase from Thymus albicans.
- Myrtus communis essential oils: insecticidal, antioxidant and antimicrobial activities: a reviewPublication . Hennia, Aicha; Nemmiche, Said; Dandlen, Susana; Miguel, Maria GracaMyrtle (Myrtus communis L.) is a wild aromatic plant that laboratorial works have demonstrated the insecticidal, antioxidant, anti-inflammatory and antimicrobial activities of myrtle essential oils (EOs). The chemical composition may change according to several factors; nevertheless, it was constant in practically all EOs the presence of 1,8-cineole and α-pinene, as main components (>5%). The biological activities, generally low or moderate depended on the organism (insecticidal) and microorganism and on the chemical composition. Generally, the contribution of the components on the biological activities was not determined; nevertheless, they were generally attributed to the presence of the main components (1,8-cineole, α-pinene, eugenol, methyleugenol, myrtenyl acetate, among other components depending on the property). The antioxidant activity of myrtle oil was predominantly determined in cell-free methods, though very few works also used cell model methods. In all cases, the activities were also low to moderate due to the absence of phenol compounds.