Browsing by Author "Figueiredo, Ana Cristina"
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- Antimicrobial and wound healing effects associated to cytocompatibility and the relationship with phytochemical profile of selected Portuguese monofloral honeysPublication . Machado, Alexandra M.; Marto, Joana; Gonçalves, Lídia Maria; Ribeiro, Helena Margarida; Duarte, Aida; Tomás, Andreia; Falcão, Soraia I.; Vilas-Boas, Miguel; Miguel, Maria da Graça; Figueiredo, Ana CristinaOwing to its applications in both food and pharmaceutical industries honey is regarded as a functional product. This study evaluated 32 Portuguese monofloral honeys and their activity was compared with manuka honey 850 +. The antimicrobial activity was determined against Gram-positive and negative bacteria, and yeast. Antioxidant activity, wound healing ability, and cell viability were studied in the human keratinocyte cell line (HaCaT). Phytochemical profile analysis was performed by UPLC/DAD/ESI-MSn. Chestnut, bell heather, eucalyptus, manuka, and strawberry tree honeys demonstrated higher antioxidant activity and were effective against S. aureus. Incense and orange honeys showed wound healing rates of 89 % and 86 %, respectively. All the honeys had cell viability above 76 %. Bell heather and strawberry tree honeys showed the highest total phenolic content, while incense and orange honeys, showed the lower ones. Phytochemical profile analysis evidenced two main clusters, one dominated by isoprenoids and norisoprenoids, as well as phenolic acids and derivatives, while the other included flavonoids as main compounds. Blending different Portuguese monofloral honeys may be an alternative to faster wound healing, by combining their diverse bioactive components. The gathered knowledge can be further explored in formulations that consider the biological activity capacity and composition of each honey.
- Biochemical characterization of Euphorbia resinifera floral cyathiaPublication . Boutoub, Oumaima; Jadhav, Sagar; Zheng, Xiongjie; El Ghadraoui, Lahsen; Al Babili, Salim; Fernie, Alisdair R.; Figueiredo, Ana Cristina; Miguel, Maria; Borghi, MonicaEuphorbia resinifera O. Berg is a plant endemic to the Northern and Central regions of Morocco known since the ancient Roman and Greek times for secreting a poisonous latex containing resiniferatoxin. However, E. resinifera pseudo -inflorescences called cyathia are devoid of laticifers and, therefore, do not secrete latex. Instead, they exudate nectar that local honey bees collect and craft into honey. Honey and cyathium water extracts find a broad range of applications in the traditional medicine of Northern Africa as ointments and water decoctions. Moreover, E. resinifera monofloral honey has received the Protected Geographic Indication certification for its outstanding qualities. Given the relevance of E. resinifera cyathia for bee nutrition, honey production, and the health benefit of cyathium-derived products, this study aimed to screen metabolites synthesized and accumulated in its pseudo -inflorescences. Our analyses revealed that E. resinifera cyathia accumulate primary metabolites in considerable abundance, including hexoses, amino acids and vitamins that honey bees may collect from nectar and craft into honey. Cyathia also synthesize volatile organic compounds of the class of benzenoids and terpenes, which are emitted by flowers pollinated by honey bees and bumblebees. Many specialized metabolites, including carotenoids, flavonoids, and polyamines, were also detected, which, while protecting the reproductive organs against abiotic stresses, also confer antioxidant properties to water decoctions. In conclusion, our analyses revealed that E. resinifera cyathia are a great source of antioxidant molecules and a good food source for the local foraging honeybees, revealing the central role of the flowers from this species in mediating interactions with local pollinators and the conferral of medicinal properties to plant extracts.
- Chemical characterization and biological properties assessment of Euphorbia resinifera and Euphorbia officinarum Moroccan PropolisPublication . Boutoub, Oumaima; El-Guendouz, Soukaina; Matos, Isabel; El Ghadraoui, Lahsen; Costa, Maria Clara; Carlier, Jorge; Faleiro, Maria Leonor; Figueiredo, Ana Cristina; Estevinho, Letícia M.; Miguel, MariaAlthough the plants of the genus Euphorbia are largely exploited by therapists in Morocco, the composition and antibacterial activities of propolis from these plants are still unknown. To address this gap, this study aimed to characterize the pollen type, the volatile compounds, and the phenolic and mineral profiles of three Euphorbia propolis samples collected in Morocco and evaluate their antimicrobial activities. The minimum inhibitory concentration of the propolis samples was determined by the microdilution method, and the anti-adherence activity was evaluated by the crystal violet assay. The examination of anti-quorum-sensing proprieties was performed using the biosensor Chromobacterium violaceum CV026. Pollen analysis revealed that Euphorbia resinifera pollen dominated in the P1 sample (58%), while E. officinarum pollen dominated in the P2 and P3 samples (44%). The volatile compounds were primarily composed of monoterpene hydrocarbons, constituting 35% in P1 and 31% in P2, with α-pinene being the major component in both cases, at 16% in P1 and 15% in P2. Calcium (Ca) was the predominant mineral element in both E. resinifera (P1) and E. officinarum (P2 and P3) propolis samples. Higher levels of phenols, flavonoids and dihydroflavonoids were detected in the E. officinarum P2 sample. The minimum inhibitory concentration (MIC) value ranged from 50 to 450 µL/mL against Gram-positive and Gram-negative bacteria. Euphorbia propolis displayed the ability to inhibit quorum sensing in the biosensor C. violaceum CV026 and disrupted bacterial biofilm formation, including that of resistant bacterial pathogens. In summary, the current study evidences the potential use of E. officinarum propolis (P2 and P3) to combat important features of resistant pathogenic bacteria, such as quorum sensing and biofilm formation.
- 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.
- Honey volatiles as a fingerprint for botanical origin: a review on their occurrence on monofloral honeysPublication . Machado, Alexandra M.; Miguel, Maria; Vilas-Boas, Miguel; Figueiredo, Ana CristinaHoneys have specific organoleptic characteristics, with nutritional and health benefits, being highly appreciated by consumers, not only in food but also in the pharmaceutical and cosmetic industries. Honey composition varies between regions according to the surrounding flora, enabling its characterization by source or type. Monofloral honeys may reach higher market values than multifloral ones. Honey's aroma is very specific, resulting from the combination of volatile compounds present in low concentrations. The authentication of honey's complex matrix, according to its botanical and/or geographical origin, represents a challenge nowadays, due to the different sorts of adulteration that may occur, leading to the search for reliable marker compounds for the different monofloral honeys. The existing information on the volatiles of monofloral honeys is scarce and disperse. In this review, twenty monofloral honeys and honeydews, from acacia, buckwheat, chestnut, clover, cotton, dandelion, eucalyptus, fir tree, heather, lavender, lime tree, orange, pine, rape, raspberry, rhododendron, rosemary, strawberry tree, sunflower and thyme, were selected for volatile comparison purposes. Taking into consideration the country of origin, the technique of isolation and analysis, the five main volatiles from each of the honeys are compared. Whereas some compounds were found in several types of monofloral honey, and thus not considered good volatile markers, some monofloral honeys revealed characteristic volatile compounds independently of their provenance.
- 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.
- The effect of nanocoatings enriched with essential oils on ‘Rocha’ pear long storagePublication . Gago, Custódia; Antão, Rui; Dores, Cristino; Guerreiro, Adriana; G, Miguel; Faleiro, Maria Leonor; Figueiredo, Ana Cristina; Antunes, Maria DulceThe effect of coating 'Rocha' pears with alginate-based nanoemulsions enriched with lemongrass essential oil (LG) or citral (Cit) was investigated. Fruit were treated with the nanoemulsions: sodium alginate 2% (w/w) + citral 1% (w/w) (Cit1%); sodium alginate 2% (w/w) + citral 2% (w/w) (Cit2%); sodium alginate 2% (w/w) + lemongrass 1.25% (w/w) (LG1.25%); sodium alginate 2% (w/w) + lemongrass 2.5% (w/w) (LG2.5%). Then, fruit were stored at 0 °C and at 95% relative humidity, for six months. Fruit samples were taken after two, four and six months, and then placed at 22 °C. Upon removal and after 7 d shelf-life, fruit were evaluated for colour CIE (L*, h◦), firmness, soluble solids content (SSC), titratable acidity (TA), weight loss, electrolytic leakage, microbial growth, symptoms of superficial scald and internal browning. All nanoemulsions had droplets in the nano range <500 nm, showed uniformity of particle size and stable dispersion. Cit-nanoemulsions had lower droplet size and higher stability than LG. No nanoemulsion showed cytotoxicity. Coatings reduced fruit colour evolution and preserved better firmness than control. After shelf-life, better firmness was found in LG-coated fruit. Coatings did not affect SSC and TA. Microbial growth was below the safety limits in all treatments. Fruit treated with LG-nanoemulsions did not show scald symptoms and panelists preferred LG1.25% coated fruit. Cit2% treated fruit showed the highest scald and internal browning symptoms, while LG1.25% did not show any disorders. This study suggests that LG-nanocoatings have the potential for preserving the quality of 'Rocha' pear.
- Trichome density in relation to volatiles emission and 1,8-Cineole synthase gene expression in Thymus albicans vegetative and reproductive organsPublication . Marques, N T.; Filipe, Alexandra; Barroso, Jose; Trindade, Helena; Power, Deborah; Figueiredo, Ana Cristina; Pinto, Patricia IS1,8-Cineole is the main volatile produced by Thymus albicans Hoffmanns. & Link 1,8-cineole chemotype. To understand the contribution of distinct plant organs to the high 1,8-cineole production, trichome morphology and density, as well as emitted volatiles and transcriptional expression of the 1,8-cineole synthase (CIN) gene were determined separately for T. albicans leaves, bracts, calyx, corolla and inflorescences. Scanning electron microscopy (SEM) and stereoscope microscopy observations showed the highest peltate trichome density in leaves and bracts, significantly distinct from calyx and corolla. T. albicans volatiles were collected by solid phase micro extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC/MS) and by GC for component identification and quantification, respectively. Of the 23 components identified, 1,8-cineole was the dominant volatile (57-93 %) in all T. albicans plant organs. The relative amounts of emitted volatiles clearly separated vegetative from reproductive organs. Gene expression of CIN was assigned to all organs analyzed and was consistent with the relatively high emission of 1,8-cineole in leaves and bracts. Further studies will be required to analyze monoterpenoid biosynthesis by each type of glandular trichome.
- Unassisted and carbon dioxide-assisted hydro- and Steam-distillation: modelling kinetics, energy consumption And chemical and biological activities of volatile oilsPublication . Sara, EL KHARRAF; EL-GUENDOUZ, Soukaina; Abdellah, Farah; El Hadrami, El Mestafa; Machado, Alexandra M.; Tavares, Cláudia S.; Figueiredo, Ana Cristina; Miguel, MariaThe demand for more suitable eco-friendly extraction processes has grown over the last few decades and driven research to develop efficient extraction processes with low energy consumption and low costs, but always assuring the quality of the volatile oils (VOs). The present study estimated the kinetic extraction and energy consumption of simultaneous hydro- and steam-distillation (SHSD), and SHSD assisted by carbon dioxide (SHSDACD), using an adopted modelling approach. The two isolation methods influenced the VOs yield, chemical composition and biological activities, namely, antioxidant, anti-glucosidase, anti-acetylcholinesterase and anti-inflammatory properties. SHSDACD provided higher VOs yields than the SHSD at a shorter extraction time: 2.8% at 30 min vs. 2.0% at 120 min, respectively, for Rosmarinus officinalis, 1.5% at 28 min vs. 1.2% at 100 min, respectively, for Lavandula angustifolia, and 1.7% at 20 min vs. 1.6% at 60 min, respectively, for Origanum compactum. The first order and sigmoid model fitted to SHSD and SHSDACD, respectively, with R2 value at 96% and with mean square error (MSE) < 5%, where the k distillation rate constant of SHSDACD was fivefold higher and the energy consumption 10 times lower than the SHSD. The rosemary SHSD and SHSDACD VOs chemical composition were similar and dominated by 1,8-cineole (50% and 48%, respectively), and camphor (15% and 12%, respectively). However, the lavender and oregano SHSDACD VOs were richer in linalyl acetate and carvacrol, respectively, than the SHSD VOs. The SHSDACD VOs generally showed better capacity for scavenging the nitric oxide and superoxide anions free radicals as well as for inhibiting α-glucosidase, acetylcholinesterase, and lipoxygenase.
- Volatile characterization of honey with dominance of Bupleurum spinosum pollenPublication . Elamine, Youssef; Machado, Alexandra M.; Estevinho, Letícia M.; Lyoussi, Badiâa; Figueiredo, Ana Cristina; Miguel, MariaMoroccan honey with Bupleurum spinosum (Apiaceae/Umbelliferae) as the main pollen source is locally known as Zantaz honey. In the present work, the volatiles from 18 honeys of this type, were isolated by hydrodistillation and analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS), for volatiles quantification and identification. The percentage composition of the volatiles and pollen profiling was used to determine the relationship between the different samples by cluster analysis. Two poorly correlated clusters were defined in volatiles analysis. Cluster A, with 17 out of the 18 samples, included four subgroups dominated by straight-chain hydrocarbons and fatty acids in variable proportions. Cluster B included just one sample, with 1-phenyldodec-1-en-3-one as the main component. Mono- and sesquiterpene hydrocarbons, as well as oxygen-containing mono- and sesquiterpenes occurred always B. spinosum and Populus sp. pollen. The one sample from Cluster B was moderately correlated with Cluster A and showed the lowest percentage of B. spinosum pollen. Pollen volatiles analysis would be relevant in assessing the presence of putative pollen volatile marker compounds and the importance of pollen profile on honey volatiles.