Percorrer por autor "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; Vilas-Boas, Miguel; Miguel, Maria 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.
- Antioxidant activity of six Portuguese thyme species essential oilsPublication . Dandlen, S. Anahi; Lima, Ana Sofia; Mendes, Marta D.; Miguel, Maria da Graça; Faleiro, Maria Leonor; Sousa, Maria João; Pedro, Luís G.; Barroso, José G.; Figueiredo, Ana CristinaThe essential oils of Thymus caespititius, T. camphoratus, T. capitellatus, T. carnosus, T. pulegioides, T. zygis subsp. zygis and T. zygis subsp. sylvestris collected in diff erent regions of Portugal, including the Azores islands, were evaluated for preventing lipid peroxidation and scavenging free radicals, and hydroxyl and superoxide anions. T. zygis subsp. zygis oil possessed the best capacity for preventing lipid peroxidation (IC50 = 0.030 ± 0.003 mg/ml), immediately followed by the oils isolated from T. zygis subsp. sylvestris collected in diff erent regions of Portugal. IC50 values ranged from 0.066 ± 0.003 to 0.087 ± 0.001 mg/ml in oils isolated from samples from Alcanena and Duas Igrejas, respectively. The oils isolated from T. zygis subsp. sylvestris, independent of the harvesting region, were shown to be the most eff ective for scavenging free radicals (0.358– 0.453 mg/ml). The best capacity for scavenging hydroxyl radicals was found in the oils of T. camphoratus collected in Espartal and of T. caespititius of Lordelo, with IC50 < 0.5 mg/ml. The low oil amount did not allow IC50 values for the superoxide anion scavenging determination, therefore considering a unique oil concentration (5 mg/ml), the highest inhibition percentages (>50%) were registered with the essential oils of T. zygis subsp. sylvestris from Duas Igrejas and Covão do Coelho, and of T. capitellatus from Sines. Copyright © 2010 John Wiley & Sons, Ltd.
- Antioxidant and Antiproliferative Activities of the Essential Oils from Thymbra capitata and Thymus Species Grown in PortugalPublication . Miguel, Maria da Graça; Gago, Custódia; Antunes, Maria Dulce; Megías, Cristina; Cortés-Giraldo, Isabel; Vioque, Javier; Lima, Ana Sofia; Figueiredo, Ana CristinaThe antioxidant and antiproliferative activities of the essential oils from Thymbra capitata and Thymus species grown in Portugal were evaluated. Thymbra and Thymus essential oils were grouped into two clusters: Cluster I in which carvacrol, thymol, p-cymene, α-terpineol, and γ-terpinene dominated and Cluster II in which thymol and carvacrol were absent and the main constituent was linalool. The ability for scavenging ABTS < sup > ·+ < /sup > and peroxyl free radicals as well as for preventing the growth of THP-1 leukemia cells was better in essential oils with the highest contents of thymol and carvacrol. These results show the importance of these two terpene-phenolic compounds as antioxidants and cytotoxic agents against THP-1 cells.
- Avaliação de propriedades biológicas em mel dos Açores – atividade antioxidante e antimicrobianaPublication . Machado, Alexandra M.; Miguel, Maria da Graça; Vilas-Boas, Miguel; Faleiro, Maria Leonor; Figueiredo, Ana CristinaO mel e os seus produtos derivados são geralmente consumidos devido às suas características nutricionais e terapêuticas, bem como igualmente empregues em fragrâncias ou cosméticos [1]. Em Portugal, existem nove denominações de origem protegida de mel reconhecidas, entre as quais a do mel dos Açores [2], cujas propriedades biológicas estão pouco estudadas. O objetivo deste trabalho consistiu no estudo de oito méis dos Açores, provenientes das ilhas de São Miguel, Santa Maria, Terceira e Pico, relativamente à quantificação do teor em compostos fenólicos totais e flavonoides, à determinação da atividade antioxidante e anti-inflamatória por métodos espetrofotométricos, bem como o controlo de qualidade microbiológico e a avaliação da atividade antimicrobiana. O teor de fenóis totais variou entre 12 μg e 460 μg equivalentes de ácido gálico (EAG)/g de mel e para os flavonóides entre 0,6 μg e 55 μg equivalentes de quercetina (EQ)/g de mel. A atividade antioxidante determinada pelo método ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) foi relativamente baixa nos oito méis, comparativamente ao padrão utilizado (Trolox), sendo apenas possível determinar o IC50 (concentração de amostra necessária para diminuir ou reduzir a concentração inicial do radical ABTS em 50%) de uma amostra, cujo valor foi 8 mg/mL. Relativamente à capacidade quelante de iões ferro(II), esta foi somente detetada em três amostras de mel, cujas percentagens de inibição variaram entre 5 e 18%. A captação do radical superóxido foi também avaliada. Os valores de IC50 variaram entre 23 e 73 mg/L. A capacidade de inibição da enzima xantina oxidase foi observada em cinco amostras de mel, sendo particularmente elevada numa delas. No que diz respeito ao controlo de qualidade microbiológico dos méis analisados, não foi observada contaminação microbiana. A atividade antimicrobiana dos oito méis foi testada contra Escherichia coli, Staphylococcus aureus, Candida albicans e Pseudomonas aeruginosa, tendo sido verificada ação inibitória dos oito méis para Escherichia coli, de quatro méis em Staphylococcus aureus e de três méis em Pseudomonas aeruginosa. Não foi observada atividade inibitória contra Candida albicans.
- Biological activity of 6,7-Dehydroxyroyleanone and derivatives obtained from Plectranthus aliciae (Codd) A.J.PatonPublication . Filipe, Márcia Santos; Domínguez-Martín, Eva M.; Pires, Tânia C.S.P.; Finimundy, Tiane C.; Melgar Castañeda, Bruno; Mandim, Filipa; Isca, Vera M. S.; Pereira, Raquel; Teixidó-Trujillo, Silvia; Capote, Natalia A.; Nikolić, Milan; Filipović, Nenad; Díaz-Lanza, Ana M.; Figueiredo, Ana Cristina; Barros, Lillian; Rijo, PatríciaThe Plectranthus genus (Lamiaceae) is known to be rich in abietane diterpenes. The bioactive 6,7-dehydroxyroyleanone (DHR, 1) was previously isolated from Plectranthus madagascariensis var. madagascariensis and var. aliciae. This study aimed to explore the occurrence of DHR, 1, in P. aliciae and the potential bioactivities of new semisynthetic derivatives from DHR, 1. Several extraction methods were evaluated, and the hydrodistillation, using a Clevenger apparatus, afforded the highest yield (77.8 mg/g of 1 in the essential oil). Three new acyl derivatives (2-4) were successfully prepared from 1 (yields of 86-95%). Compounds 1-4 showed antioxidant activity, antibacterial effects, potent cytotoxic activity against several cell lines, and enhanced anti-inflammatory activity that surpassed dexamethasone (positive control). These findings encourage further exploration of derivatives 2-4 for potential mechanisms of antitumoral, antioxidant, and anti-inflammatory capabilities, studying both safety and efficacy.
- Chemical Characterization and Biological Properties Assessment of Euphorbia resinifera and Euphorbia officinarum Moroccan PropolisPublication . Boutoub, Oumaima; El-Guendouz, Soukaïna; Matos, Isabel; El Ghadraoui, Lahsen; Costa, Maria Clara; Carlier, Jorge D.; Faleiro, Maria Leonor; Figueiredo, Ana Cristina; Estevinho, Leticia M.; Miguel, Maria GraçaAlthough 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 alpha-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 mu L/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.
- In vitro biological activity and phenolic profile of selected portuguese monofloral honeysPublication . Machado, Alexandra M.; Marto, Joana; Gonçalves, Lídia Maria; Ribeiro, Helena Margarida; Duarte, Aida; Tomás, Andreia; Falcão, Soraia; Vilas-Boas, Miguel; Miguel, Maria Graça; Figueiredo, Ana CristinaPortuguese monofloral honeys from carob tree, chestnut, bell heather, eucalyptus, incense, orange, and strawberry tree, were evaluated in vitro for antimicrobial, antioxidant, wound healing, and cell viability effect, compared to manuka honey 850+. Antimicrobial activity was determined against Gram+-and Gram- bacteria and yeast. Antioxidants, wound healing, and cell viability effects were studied in the Human Keratinocyte (HaCaT) cell line. Chestnut, bell heather, eucalyptus, manuka and strawberry tree honeys were most effective against S. aureus with a minimum inhibitory concentration (MIC) of 12.5%-25.0% (w/v), and greater ability to decrease reactive oxygen species (ROS) production (> 75%), than manuka honey (68%). Incense and orange honeys exhibited high wound healing rates, 89% and 86%, respectively, higher than manuka honey, 53%. Honeys showed cell viability > 76%. Bell heather and strawberry tree honeys exhibited the highest total phenolic content, 38 and 137 mg/100 g honey respectively, being more effective against the microorganisms tested and showing greater antioxidant activity. Opposite, incense, and orange honeys with lower phenolic amounts, 11 and 15 mg/100g honey, respectively, achieved higher wound healing ability. Flavonoid aglycones were the most abundant flavonoids in all honeys. This knowledge can be further explored in formulations that take the best out of each honey type composition and biological activity capacity.
- Levisticum officinale hairy root cultures: influence of light and light type on growth and essential oil productionPublication . Lima, Ana Sofia; Sousa, Maria João; Pedro, Luís G.; Figueiredo, Ana Cristina; Barroso, José G.; Deans, S.G.; Scheffer, J.J.C.The essential oils of Levisticum officinale W.D.J. Koch (Apiaceae), including those isolated from the roots, are used in the cosmetic, pharmaceutical and food industries [1]. This perennial and herbaceous plant, commonly known as lovage, is widely known by its aromatic, ornamental and medicinal properties. The effect of light and light type on growth and essential oil production of lovage hairy root cultures was studied by comparison of cultures maintained under “blue-basic” (400-550nm) and “day-light” 16h light photoperiod with control cultures maintained under darkness. All cultures were maintained in SH medium [2] and kept at 24ºC on orbital shakers at 80 r.p.m. Growth was evaluated by fresh weight (f.w.), dry weight (d.w.) and by the dissimilation method. The essential oil samples were isolated by distillation-extraction and analysed by GC and GC-MS. Control hairy root cultures showed a fifteen-fold d.w. biomass increase at the end of the growth period (six weeks), whereas an approximately eight-fold and ten-fold increase was obtained with “blue-basic” and “day-light” grown cultures, respectively. These differences were supported by morphological and histochemical analyses. Major changes were detected in the essential oil composition, but Z-falcarinol was in all cases the major oil constituent: in darkness, “day-light” and “blue-basic” grown cultures (75%, 94% and 61%, respectively).
- Óleos essenciais: uma solução para o controlo da Varroa?Publication . Lima, Ana Sofia; Vilas-Boas, Miguel; Figueiredo, Ana CristinaO ácaro Varroa destructor, assim como os vírus que transmite, constituem a maior ameaça da história do sector apícola mundial. Este parasita beneficia de condições favoráveis do ambiente da colónia para o seu próprio desenvolvimento e reprodução, debilitando a abelha e a colmeia, tornando-a mais suscetível a outras doenças [1]. A Varroa tem vindo a desenvolver mecanismos de resistência a alguns dos tratamentos acaricidas disponíveis no mercado, e estes acaricidas levam à acumulação de resíduos químicos nos produtos da colmeia. Para minimizar os resíduos e reduzir os custos associados à sanidade da colmeia, a utilização de fitoacaricidas, e em particular os óleos essenciais (OEs), surgem como uma alternativa atrativa para o tratamento e controlo sustentável da Varroa. No decorrer dos últimos 4 anos avaliouse a bioatividade de diversos OEs isolados de algumas espécies da flora portuguesa tais como tomilhos, lavanda, erva-príncipe, arruda, entre outras. Utilizando o método de exposição completa [2], foram realizados bioensaios de atividade acaricida dos OEs contra a Varroa e avaliada a sua toxicidade em abelhas adultas e emergentes (≤ 24h de vida), provenientes de colónias altamente infestadas com o ácaro. Testaramse 6 concentrações de OEs (0,25% a 7,5%, v/v) em condições controladas de temperatura e humidade relativa, e observou-se o efeito após 6, 12, 24 e 48h. Em simultâneo foram realizados, nas mesmas condições, brancos, controlos negativos e positivos, utilizando água, solvente e timol, respetivamente. O procedimento de avaliação dose-resposta de OEs estabelece uma eficácia de mortalidade das Varroas superior a 80% para que a atividade acaricida seja considerada ótima, registando em simultâneo uma baixa toxicidade nas abelhas adultas (<20%) [3]. Neste princípio, dos OEs avaliados, pelo menos seis mostraram com uma boa eficácia acaricida em abelhas adultas, registando valores de LC50 entre 0,04% e 2,39%, após 48h de ensaio. Adicionalmente, não se verificaram diferenças significativas entre os brancos e os controlos negativos (ANOVA: F(1, 6)=0,04; p=0,848), pelo que o potencial acaricida registado se pode atribuir efetivamente aos compostos voláteis dos OEs, tais como hidrocarbonetos monoterpénicos, monoterpenos oxigenados e fenilpropanóides. No entanto, quase todos os OEs testados revelaram ser letais para as abelhas emergentes, o que poderá dever-se ao seu estado de desenvolvimento fisiológico incompleto. Atualmente, estão a ser consideradas diferentes formulações acaricidas com os 6 OEs para posteriores ensaios de campo, abrindo portas a um potencial tratamento de inverno.
- Quality assessment of Portuguese monofloral honeys. Physicochemical parameters as tools in botanical source differentiationPublication . Machado, Alexandra M.; Tomás, Andreia; Russo-Almeida, Paulo; Duarte, Aida; Antunes, Marília; Vilas-Boas, Miguel; Miguel, Maria da Graça; Figueiredo, Ana CristinaThe quality evaluation and physicochemical parameters assessment of Portuguese monofloral honeys were performed. Fifty-one monofloral honeys were collected from several regions from mainland Portugal, and from the Azores islands, producer labelled as carob tree (n = 5), chestnut (n = 2), eucalyptus (n = 5), bell heather (n = 6), incense (n = 4), lavender (n = 8), orange (n = 9), rape (n = 2), raspberry (n = 2), rosemary (n = 1), sunflower (n = 3), and strawberry tree (n = 4). Pollen analysis and microbiological safety were evaluated, and the parameters such as colour index, moisture content, electrical conductivity, hydroxymethylfurfural, pH, free and total acidity, diastase activity, proline, and sugar profile were assessed for physicochemical characterization, in all 51 monofloral honeys. After melissopalynological examination, the honeys were either confirmed as monofloral, or classified as multifloral with predominance of a specific pollen type or multifloral. Microbiological analysis showed that honeys were safe for human consumption. Pairwise comparisons of physicochemical parameters, using only honey types with n ≥ 3, revealed significant differences between honey types. Despite some homogeneity in sugar profile among honeys, eucalyptus honey was significantly different in glucose, maltose and maltulose content compared to incense, orange and sunflower honeys, and also exhibited a higher isomaltose amount compared to all analyzed honeys. Electrical conductivity, colour index, free and total acidity, and diastase activity showed significant differences between the analyzed honeys, indicating that these parameters may provide an additional tool in monofloral honey identification.