Browsing by Author "Silva, Artur M. S."
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- 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.
- Bioactive meroditerpenes from Cystoseira abies-marina, collected from the coast of S. Miguel islandPublication . Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Silva, Artur M. S.; Kijjoa, AnakeMany substances isolated from marine organisms have demonstrated to possess interesting biological and pharmacological activities and have been used as leads in the development of new pharmaceutical agents. Marine macroalgae are abundant and structuring organisms of the coastal area of all the islands in the Azores Archipelago; some have a markedly seasonal pattern and others are perennial and present during the whole year in the Azorean coasts. One of these is Cystoseira abies-marina which grows abundantly in the coast of the Azores archipelago. Interestingly, it was observed in situ that this alga was not attacked by common predators, such as marine gastropods which led to the suggestion that the great resistance to predation of this species was due to the presence of potentially active compounds, such as antifeedant and/or cytotoxic. Preliminary study on the extracts of Cystoseira abies-marina, collected in S. Miguel Island, showed very promising results for antitumour and antioxidant activities [3]. These results have increased our interest in this alga and led to its phytochemical study. Recently, we have reported the isolation and identification of benzoic acid and two new meronorsesquiterpenes [Cystoazores A (1) and Cystoazores B (2)] from the extracts of this marine alga [4]. Further investigation of this species led to isolation of other two new meroditerpene derivatives (3 and 4). We report here the isolation of the compounds 3 and 4, from Cystoseira abies-marina whose structures were established by 1D and 2D NMR spectral analysis as well as by MS. Additionally, the cytotoxic, anti-inflammatory and antioxidant activities of compounds 1-4 were evaluated and the results will be presented.
- Biomedical applications of Inula speciesPublication . Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Artur M. S.The vast genus Inula includes species used in traditional medicine, for the treatment of inflammatory conditions, diabetes, hypertension, and also as bactericides, among other applications. Some corroboration of these ethnopharmacological applications was attempted, for instance crude extracts activity has been evaluated and the main bioactive secondary metabolites have been identified as sesquiterpene lactones. The reported activities include anti-tumour/cytotoxic and anti-inflammatory activity just to mention a few. […].
- Chemical and biological studies from an Azorean macroalga: Ulva rigidaPublication . Silva, Madalena; Vieira, Luís M. M.; Almeida, Ana Paula; Silva, Artur M. S.; Kijjoa, Anake; Seca, Ana M. L.; Barreto, Maria do CarmoNew drugs from natural sources have been targets of the drug discovery program and some bioactive compounds from macroalgae such as sulfated polysaccharides, steroids and diterpens have found their applications in the pharmaceutical industry.[1,2] Consequently, we have investigated the chemical composition and the in vitro antitumor potential of the metabolites isolated from the macroalga Ulva rigida, collected from the Azorean coast, an environmentally healthy habitat with a high level of biodiversity. We hereby describe isolation of isofucosterol (1) and 7(E)-3ẞ-hidroxy-5α, 6α-epoxymegastigmane (2) from the methanol extract of Ulva rigida, collected in May of 2011 in the Sea of St Miguel Island - Azores archipelago. The process of isolation of these metabolites involved chlorophylls elimination by the method previously described[3] and fractionation by column chromatography. The structures of 1 and 2 were established by 1D and 2D NMR spectral analysis and specific rotation as well as comparison of their spectral data with those described in the literature.[4,5] Compounds 1 and 2 were evaluated for their capacity to inhibit the in vitro growth of three human cancer cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (human skin cell line), using the protein binding dye SRB method. The results showed that compound 1 exhibited only a weak activity against MCF-7 (GI50 = 122.2 ± 17.9 μM), NCI-H460 (GI50 = 128.4 ± 32.4 μM), A375-C5 (GI50 = 119.2 ± 28.9 μM), while compound 2 was inactive against all the three cell lines (GI50 >200 μM).
- The chemical composition of the Juniperus genus (1970-2004)Publication . Seca, Ana M. L.; Silva, Artur M. S.Juniperus is an important genus widely distributed in the North hemisphere and it is used in folk medicine as well as source of cedarwood oil, a natural product with several industrial applications. The genus has attracted a great interest in the scientific communits and it has been the subject ofmore than 320 published phytochemical studies in the last 35 years. It is mainly a source of sesquiterpenes, diterpenes and lignans, some of them with very promising biological activities. The compounds identified from Juniperus species during the period 1970-2004, except essential oils fractions, are compiled in this report togetherwith the biological activities of the Juniperus extracts and of the isolated pure compounds.
- Chemical study and biological activity evaluation of two Azorean Macroalgae: Ulva rigida and Gelidium microdonPublication . Silva, Madalena; Vieira, Luís M.; Almeida, Ana Paula; Silva, Artur M. S.; Seca, Ana M. L.; Barreto, Maria do Carmo; Neto, Ana I.; Pedro, Madalena; Pinto, Eugénia; Kijjoa, AnakeThe green macroalga Ulva rigida C. Agardh (Chlorophyta) and the red macroalga Gelidium microdon Kützing (Rhodophyta), collected from the Azorean archipelago, were investigated for their secondary metabolites and their in vitro growth inhibitory effect on three human tumor cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (melanoma), as well as for their antifungal and antibacterial activities. The methanol extract of U. rigida furnished isofucosterol (1), 7(E)-3β-hydroxy-5α,6α-epoxymegastigmane (2) and (+)-dehydrovomifoliol (3) while the methanol extract of G. microdon yielded cholesterol (4) and lumichrome (5). The crude extracts of both macroalgae were found to be moderately active against the three cell lines whereas compound 1 showed a weak effect and compound 2 was inactive. The crude extracts of the two macroalgae were found to be moderately active against some fungi and bacteria while compounds 1 and 2 were inactive against all microorganisms tested.
- Compounds identified on hexane and dichloromethane extracts of Salicornia ramosissimaPublication . Isca, Vera M. S.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.; Silva, HelenaSalicornia ramosissima J. Woods (common purple glasswort) is an annual halophyte, widely distributed in the salt marsh of Ria de Aveiro (Portugal), that belongs to the Salicornia L. genus (Chenopodiaceae).[4] Although phytochemical studies genus on this genus report the presence of compounds which are well-recognized for their biological activities, such as flavonoids, chromones and alkaloids,[3] too little is known about secondary metabolites on purple glasswort. In our previous work we were able to isolate and identify ethyl o-hydroxycinnamate, (E)-fatty alcohol ferulic acid and scopoletin from the dichloromethane extract of S. ramosissima aerial parts. The structure and spectroscopic characterization of some secondary metabolites isolated from dichloromethane crude extract also will be presented and discussed.
- The current status of bioactive metabolites from the genus JuniperusPublication . Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.The genus Juniperus (family Cupressaceae) is one of the most numerous genera of the conifers (there are 102 accepted Latin binominal names). The plants are evergreen shrubs or trees, widely distributed throughout the northern hemisphere from the sea level to above timberline. Some Juniperus species are frequently used in medicinal purposes, for example Juniperus communis L. is used traditionally to cure tuberculosis while Juniperus oxycedrus L. is used in Turkey as a folk remedy in the treatment of diabetes. The richness of Juniperus species in essential oils and secondary metabolites type diterpenes, flavonoids and lignans contributes to its use in the folk medicine. Details on the most recent and relevant pharmacological studies on the bioactive secondary metabolites isolated from Juniperus species will be summarized and thoroughly discussed.
- Cystoseira abies-marina life cycle : comparative study of its polar profile by RP-HPLC-DAD-MSPublication . Seca, Ana M. L.; Lopes, Diana; Gouveia, Vera L. M.; Silva, Artur M. S.; Pinto, Diana C. G. A.Macroalgae, are largely used in food, pharmaceutical and cosmetics industries. Cystoseira abies-marina (S.G. Gmelin) C. Agardh is a brown macroalgae (Phaeophyta) which belongs to Cystoseira genus and is distributed in the Mediterranean, Macaronesian Region and the coast of Africa. In the Azores lslands, it grows abundantly in the intertidal zone where it is pioneer and attains large size. Since intertidal seaweeds are exposed to extreme stress conditions (temperatura, UV, water levei) in addition to herbivory and fouling, they develop protective mechanisms, some of which involve the biosynthesis of metabolites with properties that may be useful to man (e.g. natural antioxidants, antifouling agents, novel UV sunscreens). The dichlormethane extract of C. abies-marina from Azares was studied revealing the presence of meronorditerpenoids with cytotoxic and antioxidant activities. In this research the antioxidant activity and chemical composition of the ethyl acetate fraction of C. abies-marina methanolic extract was studied. C. abies-marina was collected in two phases of its life cycle üuvenile phase and mature phase). […].
- Cytotoxic meroterpenoids from the macroalga Cystoseira abies-marinaPublication . Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Neto, Ana I.; Kijjoa, Anake; Silva, Artur M. S.Two new meronorsesquiterpenes (cystoazorones A and B) and two new meroditerpenes (cystoazorols A and B), along with benzoic acid were isolated from the brown macroalga Cystoseira abies-marina. The structures of the new compounds were established by 1D and 2D NMR as well as HRMS spectral analysis. The in vitro cytotoxicity and antioxidant activity of the isolated compounds were also evaluated. Cystoazorones A and B, and cystoazorol A exhibited in vitro growth inhibitory activity against HeLa cells. The HeLa cell line in log phase was found to be more sensitive to cystoazorol A than when it was in lag phase. Cystoazorol A also showed a selectivity index higher than taxol, which was used as a positive control. Cystoazorols A and B were found to be the strongest antioxidants among the compounds tested.