Browsing by Author "Domingues, Maria R.M."
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- Antioxidant activities of plants enriched in rosmarinic acidPublication . Pereira, Olívia R.; Perez, María J.; Macias, Rócio I.R.; Domingues, Maria R.M.; Marín, Jose J.G.; Cardoso, Susana M.The present study aims to evaluate the in vitro antioxidant potential of Lavandula dentata and Mentha aquatica plant extracts. For that, ethanolic extracts of the two plants were prepared and their phenolic composition was determined through combined methods of HPLC-DAD and ESI-MS. Moreover, the antioxidant activity of the plant extracts was estimated by: i) evaluation of DPPH scavenging potential and ii) monitoring the protective effects against the generation of reactive oxygen species (ROS) induced by potassium dichromate in human hepatoblastoma HepG2 cells. M. aquatica ethanolic extract was much enriched in phenolic compounds, in comparison with that of L. dentata. Both extracts contained rosmarinic acid in similar concentrations but M. aquatica also contained significant amounts of other phenolics, including rutinoside derivatives of eriodictyol and luteolin. The plant extracts showed high radical scavenging activity against DPPH radical and significantly diminished intracellular ROS production under oxidative stress conditions. The latter protection was mostly evidenced in the L. dentata extract and was also observed for the rosmarinic acid used as reference. Attending that rosmarinic acid is a major phenolic component of L. dentata and M. aquatica ethanolic extracts, the present results suggest that this phenolic compound can be involved in the antioxidant properties of both plants.
- Antioxidant activities of plants enriched in rosmarinic acidPublication . Pereira, Olívia R.; Perez, María J.; Macias, Rócio I.R.; Domingues, Maria R.M.; Marín, Jose J.G.; Cardoso, Susana M.The present study aims to evaluate the in vitro antioxidant potential of Lavandula dentata and Mentha aquatica plant extracts. For that, ethanolic extracts of the two plants were prepared and their phenolic composition was determined through combined methods of HPLC-DAD and ESI-MS. Moreover, the antioxidant activity of the plant extracts was estimated by: i) evaluation of DPPH scavenging potential and ii) monitoring the protective effects against the generation of reactive oxygen species (ROS) induced by potassium dichromate in human hepatoblastoma HepG2 cells. M. aquatica ethanolic extract was much enriched in phenolic compounds, in comparison with that of L. dentata. Both extracts contained rosmarinic acid in similar concentrations but M. aquatica also contained significant amounts of other phenolics, including rutinoside derivatives of eriodictyol and luteolin. The plant extracts showed high radical scavenging activity against DPPH radical and significantly diminished intracellular ROS production under oxidative stress conditions. The latter protection was mostly evidenced in the L. dentata extract and was also observed for the rosmarinic acid used as reference. Attending that rosmarinic acid is a major phenolic component of L. dentata and M. aquatica ethanolic extracts, the present results suggest that this phenolic compound can be involved in the antioxidant properties of both plants.
- Antioxidant activities of plants enriched in rosmarinic acidPublication . Pereira, Olívia R.; Perez, María J.; Macias, Rócio I.R.; Domingues, Maria R.M.; Marín, Jose J.G.; Cardoso, Susana M.The present study aims to evaluate the in vitro antioxidant potential of Lavandula dentata and Mentha aquatica plant extracts. For that, ethanolic extracts of the two plants were prepared and their phenolic composition was determined through combined methods of HPLC-DAD and ESI-MS. Moreover, the antioxidant activity of the plant extracts was estimated by: i) evaluation of DPPH scavenging potential and ii) monitoring the protective effects against the generation of reactive oxygen species (ROS) induced by potassium dichromate in human hepatoblastoma HepG2 cells. M. aquatica ethanolic extract was much enriched in phenolic compounds, in comparison with that of L. dentata. Both extracts contained rosmarinic acid in similar concentrations but M. aquatica also contained significant amounts of other phenolics, including rutinoside derivatives of eriodictyol and luteolin. The plant extracts showed high radical scavenging activity against DPPH radical and significantly diminished intracellular ROS production under oxidative stress conditions. The latter protection was mostly evidenced in the L. dentata extract and was also observed for the rosmarinic acid used as reference. Attending that rosmarinic acid is a major phenolic component of L. dentata and M. aquatica ethanolic extracts, the present results suggest that this phenolic compound can be involved in the antioxidant properties of both plants.
- Antioxidant and anti-inflammatory activities of cytisus multiflorusPublication . Saraiva, Susana C.; Pereira, Olívia R.; Liberal, Joana; Batista, Maria T.; Domingues, Maria R.M.; Cruz, Maria T.; Cardoso, Susana M.Cytisus multiflorus(white spanish broom) is a plant used in folk medicine in the Iberian Peninsula, where it is claimed to have various health benefits. However, the usage is totally based on the available ethnopharmacological information, as no scientific data regarding its biological effects has been delivered. In this sense, is the aim of this work to contribute to the scientific knowledge of the antioxidant and anti-inflammatory properties of C. multiflorus. The extract was rich in phenolic compounds mainly chrysin-7-O-glycopyranoside and a dihydroxyflavone isomer of chrysin which accounted for 49.4±7.3 mg/g and 21.8±3.8 mg/g, respectively. The low EC50 values, determined by DPPH and reducing power assays, indicated that the C. multiflorus purified ethanolic extract has a high antioxidant capacity. Moreover, the extract did not cause cytotoxicity against RAW 264.7 macrophages for high concentrations and the treatment of this cell line with purified extract induced a significant decrease in the levels of NO. Overall, the gathered data suggests that C. multiflorus is in fact a good antioxidant and anti-inflammatory plant, as believed by the folk knowledge.
- Antioxidant and antimicrobial activities of aqueous extracts of Anthemis nobilisPublication . Pereira, Sara I.; Cardoso, Susana M.; Pereira, Olívia R.; Domingues, Maria R.M.; Ferreira, Fernanda M.Introduction: Anthemis nobilis L. (roman chamomille) is an autochthonous plant, very common in North America and in Iberian Peninsula territory. The yellow flower buttons of this plant are widely used in traditional medicine and thus, they are commonly found in herbal stores. Anthemis nobilis L. is used as a potential therapeutic agent for all body illnesses, in particular for fever, inflammatory processes, skin infections and as a tranquilizer (1). In accordance, the main goal of this work was the evaluation of A. nobilis therapeutic potential, with focus on its antioxidant and antimicrobial activities. Methodology: Aqueous extracts of A. nobilis button flowers were prepared by maceration with water at room temperature during 2 hours or by decoction. Both extracts were analysed by electrospray mass spectrometry in the negative mode and their phenolic content was determined by the Folin–Ciocalteu method (2). Antioxidant activity was evaluated through ABTS radical-scavenging activity (3),TBARS method (4) and red blood cells haemolysis (5). Potential antibacterial action of the two extracts was evaluated as the antibiogram potential, analyzing Staphyllococcus aureus and Escherichia coli growth. Results: The aqueous extracts (crude and decoccion) of A. nobilis button flowers showed high antioxidant activity, as evaluated by ABTS, TBARS and haemolysis of red blood cells assays. Moreover, this activity was higher for the decoction extract, in good agreement with its greater phenolic content. As revealed by the mass spectrometry analysis, the potent antioxidant ability of aqueous A. nobilis extracts can result from the presence of quinic acid and caffeic acid derivatives. In opposition, the two aqueous extracts of A. nobilis button flowers showed no inhibitory effect on the growth of S. aureus and E. coli (common Gram+ and Gram- bacteria), thus indicating that this plant is not is not suitable for the treatment of health problems associated to those microorganisms.
- Antioxidant capacity and toxicological evaluation of pterospartum tridentatum flower extractsPublication . Ferreira, Fernanda M.; Dinis, Lia Tânia; Azedo, Pedro; Galhano, Cristina; Cardoso, Susana M.; Domingues, Maria R.M.; Pereira, Olívia R.; Simões, Anabela; Palmeira, Carlos M.; Peixoto, Francisco P.Pterospartum tridentatum Willk. (prickled broom) is an autochthonous plant, common in Portuguese territory. The yellow flowers are used in traditional medicine, as a potential cure for all body illnesses, mainly for throat irritation treatment or for diabetes, hypertension and hypercholesterolemia therapy.Despite its traditional use, no toxicological assessment has been performed as we know. A high antioxidant activity of P. tridentatum flower water extract was acessed in good agreement with its ESI-MS spectrum that revealed the presence of several flavonoids, as luteolin-O-(O-acetyl)-glucuronide, luteolin-O- glucuronide or isorhamnetin-O-hexoside. Mitocondrial respiratory rates (state 4, state 3 and FCCP-stimulated respiration) and respiratory indexes (respiratory control and P/O ratios) showed no consistent decrease of respiratory and phosphorylative efficiencies for the concentrations tested (up to 500 μg.mL-1). Cytotoxicity evaluation, using MTT assay, was reliable with the previous results. In conclusion, for the concentration range commonly used P. tridentatum flowers usage can be regarded as harmless and trustworthy.
- Characterization of 2,3-diarylxanthones by electrospray mass spectrometry: gas-phase chemistry versus known antioxidant activity propertiesPublication . Silva, Eduarda M.P.; Barros, Cristina M.R.F.; Santos, Clementina M.M.; Barros, António S.; Domingues, Maria R.M.; Silva, ArturXanthones (XH) are a class of heterocyclic compounds widely distributed in nature that hold numerous noteworthy biological and antioxidant activities. Therefore, it is of utmost importance to achieve relevant detailed structural information to understand and assist prediction of their biological properties. The potential relationship between radical-mediated xanthone chemistry in the gas phase and their promising antioxidant activities has not been previously explored.
- Characterization of new phenolic derivatives in Portuguese propolis by electrospray mass spectroscopyPublication . Falcão, Soraia; Vilas-Boas, Miguel; Freire, Cristina; Domingues, Maria R.M.; Cardoso, Susana M.This research outlines an extensive characterization of the phenolic composition of a propolis sample from the northeast of Porto gal. For that, ao ethanolic extract was prepared, fractionated by HPLC and the identification of the phenolic compounds was done by electro spray mass spectrometry in the negative mode. This technical approach allowed the identification of 37 phenolic compounds in the Portoguese propolis sample, including seven that were described for the first time. Two of these new compounds had [M-Hr ions at mlz 403, aod the others had [M-Hr ions at mlz 433, mlz 461, mlz 417, mlz 475, and mlz 565. In general, the molecular weight of these compounds was higher thao the common phenolic compounds of propolis aod their fragmentation pattern suggested that they belong to the flavonoid family probably lioked with a phenylpropanoic acid moiety in the position C5 (mlz 403, 433, 461, 475) and C3 (mlz 403, 417), corresponding to pinocembrio and pinobaoksin derivatives. The ion at mlz 565 seems to be a p-counlaric ester derivative dimer.
- Characterization of new phenolic derivatives in Portuguese propolis by electrospray mass spectroscopyPublication . Falcão, Soraia; Vilas-Boas, Miguel; Freire, Cristina; Domingues, Maria R.M.; Cardoso, Susana M.Propolis is a resinous substance collected by honeybees from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. This product is widely used in traditional medicine [I] and it has recently gained popularity as a health food supplement. Currently, it is extensively used in foods and beverages, and it is claimed to improve health and prevent diseases such as inflammation, heart disease, diabetes and cancer.
- Characterization of the phenolic constituents and the antioxidant activity of cytisus multiflorusPublication . Pereira, Olívia R.; Domingues, Maria R.M.; Cardoso, Susana M.The specific interest in naturally occurring antioxidants has lead to an exponential investigation of many traditional medicinal plants, as they are potential candidates for finding new therapeutic and supplementary health products. Cytisus multiflorus, also known as White Spanish Broom, is a leguminous shrub native from Iberian Peninsula that is u sed in folk medicine mainly due to its diuretic and anti-inflammatory properties. Still, despite its common usage for centuries, this plant has been far less studied than other species of the same genus. This study aimed to determine the phenolic composition and to evaluate the antioxidant capacity of Cytisus multiflorus. For that, an ethanolic extract was prepared and its total phenolics and flavone contents were determined. The antioxidant activity was accessed by measuring the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging potential. Also, the extract was fractionated by reversed-phase HPLC and the major phenolic compounds of each fraction were identified by ESI-MS and MSn analysis, in order to establish the specific phenolic profile of the plant. The total amount of phenolic compounds and of flavones accounted for 140 mg/g and 47 mg/g of the ethanolic extract from Cytisus multiflorus, respectively. Also, it exhibited a high antioxidative capacity, with an EC50 value of 29,7 μg/ml. Moreover, the interpretation of the fragmentation pathways under ESI-MS/MS of the collected HPLC fractions allowed concluding that the main phenolic compounds in the plant included chrysin and some glycoside derivatives of luteonine and quercetin. Thus, the overall results suggest that the phenolic extract of the Cytisus multiflorus can be claimed as a good source of natural antioxidants.