Browsing by Author "Bernardo-Gil, M.G"
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- Composition of Myrtus communis L. Essential Oils as Affected by Climatic ConditionsPublication . Pereira, Paula.; Cebola, Maria João.; Bernardo-Gil, M.GMyrtus Communis L. (Myrtaceae family), commonly known as myrtle, possesses a set of qualities that make it very interesting for the pharmaceutical, nutraceutical and cosmetic industries. In this work, myrtle was studied over a period of three years (2006-2008), encompassing the main stages of the development cycle of the plant. The influence of climatic conditions, such as temperature and rainfall, on the chemical composition and yield of the essential oils obtained from leaves and berries was studied. The leaves and berries essential oils were obtained by Clevenger distillation and analysed by GC and GC-MS. The results show that the major components were limonene+1,8-cineole, myrtenyl acetate, α-pinene and linalool. Over the three year period of study, a decrease in the composition of the most volatile compounds (α-pinene and limonene+1,8-cineole) was observed, the reverse being found for linalool and myrtenyl acetate. The highest value for the yield of the leaves’ essential oils was observed in the third year (0.64%, w/w), whereas that same year the lowest yield (0.07%, w/w) of fruit was observed. These results were likely due to an atypically high record for rainfall in April and May of that year. The highest value of the berry essential oils (0.14%, w/w) was obtained in the second year.
- HPLC/MS identification of the polyphenols present in an extract of Myrtus communis L. obtained by supercritical fluid extractionPublication . Pereira, P.; Cebola, M.J.; Oliveira, M.C; Bernardo-Gil, M.GNeste trabalho, estudámos um extrato obtido por extração de fluido supercrítica (ESC) usando um método mais simples de adição de co-solvente (etanol). Em vez de usar uma bomba de líquidos, que é o processo mais comum, o etanol foi introduzido diretamente na célula de extração, imediatamente após o carregamento da célula com a amostra de planta. Pretendeu-se investigar se esta alteração teria algum efeito na composição do extrato obtido. As condições experimentais utilizadas foram: temperatura 48 °C, pressão 10 MPa, caudal de fluido supercrítico (FSC) 130,71 dm3h-1 (0,238 kgh-1) e um volume de etanol de 104 cm3. Os compostos identificados por HPLC MS neste extrato foram o ácido quínico, o ácido quínico 3,5-di-O-galato, o ácido 3,4,5-galoilquinico, a miricetina galactósido-galato, a quercetina-galactósido-galato, a miricetina-galactósido e a quercetina-ramnósido).