Search results

Disponível na Biblioteca da ESACB na cota C30-29416TFCBA

Caracterização do perfil fenólico em extratos de flores de acácia spp.

info:eu-repo/semantics/publishedVersion

The purpose of this work is to evaluate the wine spirit aged by an alternative process (staves combined with different micro-oxygenation levels) and its comparison with the traditional process (wooden barrels). This evaluation was made by analyzing the volatile compounds and sensory profile of the spirits during 365 days of ageing. The findings confirmed the role played by oxygen in the volatile profile of aged wine spirits. Samples of alternative ageing modalities were well distinguished from those of wooden barrels based on the volatile profile, namely on the concentrations of several volatile phenols. From a sensory point of view, the results are promising with high overall consistency scores obtained from samples of alternative ageing process modalities.

Many species of the so-called exotic plants coexist with native species in a balanced way, but others thrive very quickly and escape human control, becoming harmful—these are called invasive alien species. In addition to overcoming geographic barriers, these species can defeat biotic and abiotic barriers, maintaining stable populations. Ailanthus altissima is no exception; it is disseminated worldwide and is considered high risk due to its easy propagation and resistance to external environmental factors. Currently, it has no particular use other than ornamental, even though it is used to treat epilepsy, diarrhea, asthma, ophthalmic diseases, and seborrhoea in Chinese medicine. Considering its rich composition in alkaloids, terpenoids, sterols, and flavonoids, doubtlessly, its use in medicine or other fields can be maximised. This review will focus on the knowledge of the chemical composition and the discovery of the biological properties of A. altissima to understand this plant better and maximise its possible use for purposes such as medicine, pharmacy, or the food industry. Methods for the extraction and detection to know the chemical composition will also be discussed in detail.

Acacia spp. is an invasive species that is widespread throughout the Portuguese territory. Thus, it is pertinent to better understand this species in order to find different applications that will value its use. To evaluate the phenolic profile in Acacia flowers, ethanolic extracts obtained through an energized guided dispersive extraction were analysed, focusing on two species, Acacia retinodes and Acacia mearnsii, at two flowering stages. The phytochemical profile of each extract was determined by ultra-high performance liquid chromatography coupled with quadrupole time-offlight mass spectrometry and high-performance liquid chromatography coupled with diode array detector. The FTIR-ATR technique was used to distinguish the different samples’ compositions. The results showed the presence of high concentrations of phenolic compounds (>300 mg GAE/g extract), among which are flavonoids (>136 mg QE/g extract), for all combinations of species/flowering stages. The phytochemical profile showed a complex composition with 21 compounds identified and quantified (the predominant ones being epicatechin, rutin, vanillin, and catechol). Both species and flowering stages presented significant variations regarding the presence and quantity of phenols and flavonoids, so much so that a principal component analysis performed with FTIR-ATR spectra data of the extracts was able to discriminate between species and flowering stages.

Natural products are increasingly becoming part of our daily lives through their use in industry, food, as therapeutic agents, etc. To evaluate their possible applications, it is essential to characterize them chemically to explore their potential. Different techniques may be used to characterize natural products, including microextraction techniques. These techniques have been gaining popularity due to the advantages associated with their low use of organic solvents and the small amount of sample used relative to more classical sample preparation techniques. Their application in the extraction of compounds from natural products is still scarce. This manuscript intends to review the most used solid-based miniaturized sample preparation techniques applied to determining compounds in natural products. The main applications of these methodologies will be discussed, with a particular focus on natural product analysis, as well as their advantages and disadvantages over traditionally used sample preparation techniques.

Devido à sua elevada incidência, a infertilidade tornou-se uma questão de saúde pública proeminente, representando um desafio significativo para a medicina reprodutiva moderna. Algumas condições clínicas que levam à infertilidade feminina incluem a síndrome de ovários poliquísticos (PCOS), endometriose, e falência ovárica prematura (FOP). O fluido folicular (FF) é a matriz biológica que tem mais contacto com o oócito, podendo ser utilizado como um preditor da sua qualidade1. A volatilómica surge como um método não invasivo, direto, acessível e simples para a caracterização de várias doenças. Este estudo teve como objetivo determinar o padrão volatómico do fluido folicular de pacientes com PCOS, endometriose, e POF, e encontrar potenciais biomarcadores destas condições clínicas. Para analisar os compostos orgânicos voláteis (VOCs) presentes em amostras de FF de mulheres inférteis foi utilizada a microextração em fase sólida em modo headspace e posterior análise por GC-MS. Foram identificados 136 VOCs em 52 amostras, correspondendo a 15 pacientes com PCOS, 8 com endometriose, 12 com POF, e 17 controlos. Devido à sua prevalência em todas as amostras, apenas 37 compostos foram considerados, e a análise estatística multivariada revelou alterações significativas nos níveis de certos metabolitos de acordo com cada condição clínica. Os perfis bioquímicos analisados revelaram vias metabólicas comprometidas, bem como a presença de compostos fortemente ligados com infertilidade2. Esta metodologia abre a porta para a investigação das diversas vias metabólicas relevantes para o correto funcionamento do sistema reprodutor, bem como a melhoria das ferramentas de diagnóstico existentes.