Filipe Monteiro-Silva

arXiv2014

Olive oil's polyphenolic metabolites - from their influence on human health to their chemical synthesis

English version of abstract A growing number of scientific researches have been demonstrating that olive oil operates a crucial role on the prevention of cardiovascular and tumoral diseases, being related with low mortality and morbidity in populations that tend to follow a Mediterranean diet. Amongst its minor components, polyphenols have been subject to several clinical trials that have established health benefits associated to their antioxidant, antitumoral and anti-atherosclerotic activity. However the biological activity of polyphenols is dependent not only of their absorption but also of their metabolization. Bioavailability studies have demonstrated that after olive oil intake, not only hydroxytyrosol but also its metabolites can be found in plasma, such as 3,4-dihydroxyphenylacetaldehyde, 3,4-dihydroxyphenylacetic acid, homovanillyl alcohol and its glucoronides. ----- Portuguese version of abstract Um numero crescente de pesquisas cientificas demonstram que o azeite opera um papel crucial na prevençao de doenças cardiovasculares e doenças tumorais, estando relacionado com a baixa mortalidade e morbilidade em populaçoes que tradicionalmente seguem uma dieta Mediterranica. De entre os seus componentes minoritários, os polifenois têm vindo a ser alvo de estudos clinicos que demonstraram o seu benefício para a saude pela atividade antioxidante, anti-tumoral e anti-aterosclerotica que possuem. No entanto a atividade biológica destes polifenois é dependente nao só da sua absorçao como poderá tambem depender da sua metabolizaçao. Estudos de biodisponibilidade demonstraram que após o consumo de azeite encontram-se no plasma nao só hidroxitirosol, mas igualmente os seus metabolitos, tais como o ácido 3,4-dihidroxifenilacetico, o 3,4-dihidroxifenilacetaldeido, o álcool homovanilico e os respectivos glucoronideos.

q-bio.BM↗

arXiv2013

Evolution through time of Pyrrolizidine Alkaloids detection and quantification

Pyrrolizidine Alkaloids (PAs) are a group of naturally occurring alkaloids that are produced by plants as a defense mechanism against insect herbivores. The analytical methodologies employed for their detection have come a long way since the first analytical experiment and in the last 30 years had an enormous development, both technological and experimental. It is notorious that before the generalization of certain technologies, especially in a post-war atmosphere, most scientific researches relied on what it is today thin-layer chromatography. Nevertheless this technique was not sufficient for accurately measure quantities and unambiguously identify compounds, therefore spectroscopic techniques arose as well as chromatographic techniques. While the first never really coped with PAs analysis requirements the latter, either as gas or liquid chromatography allowed the analysis of complex sample matrices. Simultaneously, nuclear magnetic resonance also suffered significant developments while mass spectrometry has become an attractive technique due to increasingly higher maximum resolutions. The observed tendency in recent years, in pyrrolizidine detection and quantification, as well as in many other areas, is that hyphenated techniques are the chosen methods. A large number of papers report multihyphenated methodologies, and the overwhelming majority relies on gas or liquid chromatography.

q-bio.BM↗