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Avaliação do potencial farmacológico de metabolitos secundários de Cystoseira abies-marina
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Abstract(s)
A pesquisa de Produtos Naturais com propriedades farmacológicas tem vindo a crescer, destacando-se a descoberta de moléculas vindas de organismos marinhos, que devido à sua considerável biodiversidade se reflecte em metabolitos secundários com estruturas únicas e com várias funcionalidades. Este trabalho surge no seguimento de uma investigação feita com algas do mar dos Açores, cujas actividades biológicas se mostraram promissoras. Nesta tese intitulada “Avaliação do potencial farmacológico de metabolitos secundários de Cystoseira abies-marina”, faz-se um estudo fitoquímico e determinam-se algumas actividades biológicas de compostos isolados. No capítulo I apresentam-se os objectivos e faz-se uma descrição das características da alga em estudo, bem como um pequeno resumo da literatura referente aos compostos isolados de algas do género Cystoseira. A elucidação estrutural dos cinco compostos isolados (o ácido benzóico, um composto natural já conhecido, o cystoazores A, o cystoazores B, o cystoazorona A e o cystoazorona B, meroditerpenos isolados pela primeira vez), e as actividades destes compostos (antitumoral, antioxidante, anticolinesterásica e anti-inflamatória) são apresentadas e discutidas no Capitulo II. Os resultados mostram que os compostos cystoazores A, cystoazores B e cystoazorona A apresentam actividade antitumoral, mas com baixa selectividade entre a linhagem tumoral HeLa e a linhagem não tumoral Vero usada como referência. Na actividade antioxidante, nenhum dos compostos testados apresentaram IC50 <500 μg/mL.. Os compostos mais activos como anticolinesterásicos foram o cystoazores A e B, apesar de não terem atingido 50% de inibição da enzima à concentração máxima testada (125 μg/mL). Quanto à actividade anti-inflamatória in vitro, o ácido benzóico e a cystoazorona B foram os únicos que inibiram ambas as formas da cicloxigenase (COX1 e COX2), comportando-se no entanto como pro-inflamatórios em relação à lipoxigenase 15-LOX. No capítulo III são apresentados os detalhes dos procedimentos experimentais utilizados neste trabalho de investigação.
ABSTRACT: The search for Natural Products with pharmacological properties has been increasing, particularly the discovery of molecules isolated from marine organism, whose considerable biodiversity is reflected in secondary metabolites with unique structures and functions. This work is carried out in the sequence of a preliminary investigation on the marine algae of the Azores, which detected promising biological activities. In this thesis, entitled “Evaluation of the pharmacological potential of secondary metabolites from Cystoseira abies-marina”, a phytochemical study is carried out and several biological activities of isolated compounds are determined. Chapter I presents the objectives and characterizes the under study, and also a summary of the literature concerning compounds isolated from the Cystoseira genus. The structural elucidation of five isolated compounds (benzoic acid, a known natural compound, cystoazores A, cystoazores B, cystoazorone A and cystoazorone B, meroditerpenes isolated for the first time) and the activity of these compounds (antitumour, antioxidant, anticholinesterasic and anti-inflammatory) are presented and discussed in Chapter II. The results show that cystoazores A, cystoazores B and cystoazorone A are actively cytotoxic, but with low selectivity between HeLa tumour cell line and Vero non tumour cell line, used as reference. Concerning antioxidant activity, none of the compounds tested presented IC50<500 μg/mL. Cystoazores A and B had the strongest anticholinesterasic activity, although 50% inhibition of enzyme activity was not attained at the highest concentration tested (125 μg/mL). Regarding in vitro anti-inflammatory activity, benzoic acid and cystoazorone B were the only two that inhibited both isoforms of cyclooxygenase (COX1 and COX2), although they behaved as pro-inflammatory towards lipoxygenase 15-LOX. Chapter III presents details of experimental procedures used in this research.
ABSTRACT: The search for Natural Products with pharmacological properties has been increasing, particularly the discovery of molecules isolated from marine organism, whose considerable biodiversity is reflected in secondary metabolites with unique structures and functions. This work is carried out in the sequence of a preliminary investigation on the marine algae of the Azores, which detected promising biological activities. In this thesis, entitled “Evaluation of the pharmacological potential of secondary metabolites from Cystoseira abies-marina”, a phytochemical study is carried out and several biological activities of isolated compounds are determined. Chapter I presents the objectives and characterizes the under study, and also a summary of the literature concerning compounds isolated from the Cystoseira genus. The structural elucidation of five isolated compounds (benzoic acid, a known natural compound, cystoazores A, cystoazores B, cystoazorone A and cystoazorone B, meroditerpenes isolated for the first time) and the activity of these compounds (antitumour, antioxidant, anticholinesterasic and anti-inflammatory) are presented and discussed in Chapter II. The results show that cystoazores A, cystoazores B and cystoazorone A are actively cytotoxic, but with low selectivity between HeLa tumour cell line and Vero non tumour cell line, used as reference. Concerning antioxidant activity, none of the compounds tested presented IC50<500 μg/mL. Cystoazores A and B had the strongest anticholinesterasic activity, although 50% inhibition of enzyme activity was not attained at the highest concentration tested (125 μg/mL). Regarding in vitro anti-inflammatory activity, benzoic acid and cystoazorone B were the only two that inhibited both isoforms of cyclooxygenase (COX1 and COX2), although they behaved as pro-inflammatory towards lipoxygenase 15-LOX. Chapter III presents details of experimental procedures used in this research.
Description
Dissertação de Mestrado em Ciências Biomédicas.
Keywords
Cystoseira abies-marina Antitumoral Antioxidantes Anti-inflamatórios Anticolinesterásicos Meroditerpenos Metabolitos Secundários Antitumour Antioxidant Anti-inflammatory Anticholinesterasic Meroditerpenes Secondary Metabolites
Citation
Gouveia, Vera Lúcia Mendes – "Avaliação do potencial farmacológico de metabolitos secundários de Cystoseira abies-marina". Ponta Delgada : Universidade dos Açores. 2012. XII, 94 p.. Dissertação de Mestrado.