Browsing by Author "Seca, Ana M. L."
Now showing 1 - 10 of 77
Results Per Page
Sort Options
- 2019 é o Ano Internacional da Tabela Periódica dos Elementos QuímicosPublication . Seca, Ana M. L.[…]. A Tabela Periódica é um quadro com 18 colunas e 7 linhas (não incluindo as terras raras), onde estão todos os elementos químicos conhecidos ate a data (91 existentes na natureza e 27 produzidos em laboratório), organizados por ordem crescente do número atómico de cada elemento. O que a Tabela Periódica tem de tão extraordinário, é que justifica ser-lhe dedicada 12 meses de comemorações, e o facto de nela estar resumido tudo o que existe no universo, é organizado de tal forma que as propriedades físicas e químicas dos elementos exibem uma variação periódica ao longo de cada linha (período) e de cada coluna (grupo). Esta organização permite, facilmente, compreender, reconhecer e prever a forma como cada elemento químico se comporta na natureza e em laboratório. Torna-se assim possível compreender, por exemplo, o porque de alguns elementos químicos se encontrem sempre na forma combinada com outros, dando origem a uma diversidade de substâncias quase incontável, enquanto outros elementos só existem na forma elementar pura. […].
- Advances on Applications of Bioactive Natural CompoundsPublication . Seca, Ana M. L.; Gallardo, Eugenia
- An overview of Salicornia genus : the phytochemical and pharmacological profilePublication . Isca, Vera M. S.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.Salicornia L. (Chenopodiaceae) is a genus of annual, apparently leafless halophytic herb that have articulated and succulent stems. The Salicornia species comprise the most salttolerant land plant and frequently occur in saline areas. The use of glasswort as food is referred by the forensic palynology as a reality at least from 550 years ago. Nowadays it is much appreciated as a gourmet product in Europe but particularly in Asian countries, where is used in fresh salads and pickles. Some of the Salicornia species display applications on folk medicine (for treatment of bronchitis, hepatitis and diarrhea) and showed important biological properties such as antioxidant, anti-inflammatory, hypoglycemic and cytotoxic activities. The phythochemical studies on this genus reported the presence of fatty acids, sterols, saponins, chlorogenic acid derivatives, alkaloids, flavonoids and other kind of phenolic compounds.The purpose of this review is to highlight the advances in Salicornia genus knowledge by presenting its biological and medicinal applications, phytochemical studies and the relationship between the isolated compounds with the described biological and/or medicinal properties.
- Anti-aging activity of Lobophora variegata ethanolic and methanolic extracts and their fractionsPublication . Rosa, Gonçalo P.; Costa, Ana C.; Medeiros, D.; Seca, Ana M. L.; Barreto, Maria do CarmoSeaweed have promising applications within food, cosmetic and health industries, which led to an increased interest in studying these organisms [1]. In several coastal areas, thousands of tons of macroalgae are cast on beaches and shorelines and it would be very interesting if this biomass could be managed, allowing the extraction of added-value compounds. In this context, polar extracts (methanol and ethanol) of a macroalgal beach cast sample mainly composed of “Lobophora variegate” were prepared and the anti-aging and antioxidant activities were evaluated. The preliminary results showed interesting results, and thus these crude extracts were then fractionated sequentially by their solubility in dichloromethane, acetone and ethyl acetate, resulting in 4 semi-pure fractions each, which were also tested. Fractions A1.1.1 and A1.2.3 were very good tyrosinase inhibitors (IC₅₀ = 37.87 and 24.01 μg/mL, respectively) and fractions A1.1.2 and A1.2.2 presented very good inhibition of elastase (IC₅₀ = 44.76 and 20.86 μg/mL, respectively). However, none of the fractions was active against collagenase. These results show that further purifications of these fractions can lead to the isolation of bioactive added-value compounds.
- Antioxidant activity evaluation from Artemisia gorgonum extractsPublication . Rodrigues, Neidy; Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Helena; Pereira, M. LourdesArtemisia gorgonum (Asteraceae) known as “losna or lorna” is used in Cape Verde in traditional medicine to treat inflammation, fever and gastroenteritis. The antioxidant activity of methanol, 70% ethanol, chloroform-methanol and chloroform extracts from A. gorgonum leaves was evaluated using the DPPH assay and the results presented.
- Antioxidant and anticholinesterasic activities of Morella faya (Aiton) Wilbur extractsPublication . Silva, Bruno J. C.; Seca, Ana M. L.; Moreno-Rodriguez, L.; Barreto, Maria do CarmoMorella faya (Aiton) Wilbur (Myricaceae), formerly Myrica faya, is a shrub or small tree native to Macaronesia, Spain and Portugal and invasive in Hawai'i [1]. In the present study, bioactivities of extracts from leaves and bark collected in S. Miguel, Azores, were determined. Extracts were prepared by sequentially extracting the dry material with dichloromethane and acetone at room temperature. The antioxidant activity of the extracts was determined by the DPPH radical scavenging and FeCl3 reduction assays, total phenolics by the Folin-Ciocalteau method and in vitro anticholinesterasic (anti-AChE) activity by a modification of the Ellman method [2]. The dichloromethane extracts did not present any of these activities between 4.9 and 1250 µg/mL. Both acetone extracts presented a high antioxidant activity. For the DPPH scavenging activity, EC50= 17.7 ± 0.13 and 16.9 ± 0.36 µg/mL for leaves and bark, respectively and 4.5 ± 1.1 µg/mL for quercetin (positive control). In the FeCl3reduction assay, EC50 values were 3.8 ± 0.40 and 3.9 ± 0.16 µg/mL for leaves and bark respectively, and 0.995 ± 0.06 µg/mL for gallic acid (positive control). The acetone extracts also showed anti-AChE activity, stronger for the bark, with IC50= 82.9 ± 6.16 µg/mL and weaker for the leaves, with IC50= 333.0 ± 27.3 µg/mL, which are interesting values for whole extracts. Anti-AChE activity was inversely proportional to the amount of phenolic compounds, 639.3 ± 17.8 mg GAE/g of leaf extract and 95.3 ± 6.55 mg GAE/g of bark extract, therefore the compounds responsible for this effect do not belong to this group. The antioxidant activity cannot be explained by the amount of these compounds alone, since it was quite similar for both acetone extracts and did not therefore reflect the differences in polyphenol content.
- Antitumor activities of invasive allien species from the AzoresPublication . Bettencourt, Ana; Pereira, Joana M.; Costa, Ana C.; Seca, Ana M. L.; Barreto, Maria do Carmo
- Applications of sesquiterpene lactones : a review of some potential success casesPublication . Moujir, Laila M.; Callies, Oliver; Sousa, Pedro M. C.; Sharopov, Farukh; Seca, Ana M. L.Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.
- Aqueous and Ethanolic Plant Extracts as Bio-Insecticides : Establishing a Bridge between Raw Scientific Data and Practical RealityPublication . Tavares, Wilson R.; Barreto, Maria do Carmo; Seca, Ana M. L.Global demand for food production is causing pressure to produce faster and bigger crop yields, leading to a rampant use of synthetical pesticides. To combat the nefarious consequences of its uses, a search for effective alternatives began in the last decades and is currently ongoing. Nature is seen as the main source of answers to crop protection problems, supported by several examples of plants/extracts used for this purpose in traditional agriculture. The literature reviewed allowed the identification of 95 plants whose extracts exhibit insecticide activity and can be used as bio-pesticides contributing to sustainable agriculture. The option for ethanol and/or water extracts is more environmentally friendly and resorts to easily accessible solvents, which can be reproduced by farmers themselves. This enables a bridge to be established between raw scientific data and a more practical reality. Azadirachta indica, Capsicum annuum, Nicotiana tabacum and Tagetes erecta are the most researched plants and have the potential to be viable options in the pest management approach. Azadirachta indica showed the most promising results and Brevicoryne brassicae was the most targeted pest species, being tested against the aqueous and/or ethanolic extracts of 23 different plants. Maceration using dried material (usually leaves) is the extraction method preferred by the majority of authors.
- Asparagopsis armata da costa Açoriana : uma alga em estudoPublication . Seca, Ana M. L.A alga vermelha Asparagopsis armata (figura 1), é nativa do hemisfério Sul, mas atualmente está distribuída desde o Atlântico Norte ate a costa do Senegal incluindo a bacia do Mediterrâneo. É considerada uma alga invasora que causa um impacto negativo quer na biodiversidade quer indiretamente na economia ao afetar o turismo, a pesca e a aquicultura. O ciclo de vida da Asparagopsis armata decorre em duas fases dotadas de morfologias muito distintas sendo que é na 2.ª fase que esta alga apresenta maior biomassa e maior potencial tecnológico e comercial. […].