| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.4 MB | Adobe PDF |
Advisor(s)
Abstract(s)
As plantas aromáticas têm vindo a ser cada vez mais investigadas como fonte de propriedades medicinais e farmacêuticas, devido aos diferentes compostos bioativos que produzem. O eucalipto, nomeadamente a espécie Eucalyptus globulus, é fonte de matéria-prima para as indústrias madeireira e de celulose, sendo também muito utilizado pelas indústrias farmacêutica e de perfumaria, pela sua viabilidade mundialmente reconhecida enquanto fonte de óleo essencial. Assim, este estudo teve como objetivo proceder à caracterização química de óleos essenciais (OE) de eucalipto (E. globulus), a partir de folhas com diferente origem geográfica e nível de desenvolvimento (árvores adultas e jovens) e de frutos, tendo sido estes extraídos em sistema de Clevenger, bem como de OE adquiridos comercialmente. Adicionalmente, efetuou-se a avaliação de propriedades biológicas (atividade antimicrobiana e antioxidante) dos referidos OE.
O composto maioritariamente presente nos OE estudados foi o Eucaliptol (1,8-cineol), apresentando uma maior percentagem nos óleos comerciais (93,3% e 97,0%) comparativamente aos extraídos por hidrodestilação. Destes, o OE do fruto foi o que apresentou o menor teor do composto maioritário (24,1%,), sendo o conteúdo similar entre as diferentes amostras de folhas (61,9%, 62,5%, 67,8%). Na avaliação dos fenóis totais dos extratos etanólicos, a folha colhida na região do Douro Litoral foi a que apresentou um teor superior (136,50±14,54 mg EAG/g extrato). Todos os extratos etanólicos demonstraram ter propriedades antioxidantes, sendo a amostra da folha do Douro Litoral a que demonstrou melhores resultados nas diferentes metodologias realizadas, estando de acordo com o seu teor de fenóis totais obtido. Como esperado, verificou-se um valor baixo no teor de fenóis totais dos óleos essenciais (entre 0,97±0,18 e 2,35±0,18 mg EAG/g óleo). No que respeita à atividade antimicrobiana, os óleos essenciais comerciais e extraídos das folhas apresentaram atividade bactericida face a todos os microrganismos estudados, à exceção de Pseudomonas aeruginosa, apresentando o OE do fruto uma atividade antimicrobiana inferior visto que foi a amostra que inibiu menos bactérias.
Conclui-se, desta forma, que o eucalipto pode ser uma potencial fonte de antimicrobianos e antioxidantes naturais de interesse para diferentes indústrias.
Aromatic plants have been increasingly investigated as a source of medicinal and pharmaceutical properties, due to the different bioactive compounds that they produce. Eucalyptus, especially the species Eucalyptus globulus, is a source of raw material for the wood and pulp industries and is also widely used by the pharmaceutical and perfumery industries for its globally recognized viability as a source of essential oil. The objective of this study was to characterize the chemical composition of different E. globulus essential oils (EO), obtained by hydrodestillation from leaves collected from different geographic origins and level of development (adult and young trees) and fruits, as well as two EO commercially acquired. In addition, the evaluation of biological properties (antimicrobial and antioxidant activity) of the EOs was performed. The major compound found in all samples was Eucalyptol (1,8-cineol), with the commercial oils presenting higher contents (93,3% and 97,0%) compared to the EO extracted by hydrodistillation. Of these, the EO from the fruit was the one that presented the lowest content of the major compound (24,1%), with the different leaf samples presenting similar amounts (61,9%, 62,5%, 67,8%). The ethanolic extracts were evaluated for total phenolic compounds content and the leaf sample harvested in the Douro Litoral region was the one that presented the highest content (136,50 ± 14,54 mg EAG / g extract). All the ethanolic extracts showed antioxidant properties, with the Douro Litoral sample being the one that demonstrated better results in the different assayed methodologies, which is in good agreement with its higher phenolics content. As expected, the essential oils presented very low levels of total phenolic compounds (ranging from 0,97 ± 0,18 to 2,35 ± 0,18 mg GAE /g oil). Regarding the antimicrobial activity, the commercial essential oils and those extracted from the leaves presented bactericidal activity against all the studied microorganisms, with the exception of Pseudomona aeruginosa, with the fruit EO having a lower antimicrobial activity. In sum, eucalyptus can be a potential source of natural antimicrobials and antioxidants intereting to different industries.
Aromatic plants have been increasingly investigated as a source of medicinal and pharmaceutical properties, due to the different bioactive compounds that they produce. Eucalyptus, especially the species Eucalyptus globulus, is a source of raw material for the wood and pulp industries and is also widely used by the pharmaceutical and perfumery industries for its globally recognized viability as a source of essential oil. The objective of this study was to characterize the chemical composition of different E. globulus essential oils (EO), obtained by hydrodestillation from leaves collected from different geographic origins and level of development (adult and young trees) and fruits, as well as two EO commercially acquired. In addition, the evaluation of biological properties (antimicrobial and antioxidant activity) of the EOs was performed. The major compound found in all samples was Eucalyptol (1,8-cineol), with the commercial oils presenting higher contents (93,3% and 97,0%) compared to the EO extracted by hydrodistillation. Of these, the EO from the fruit was the one that presented the lowest content of the major compound (24,1%), with the different leaf samples presenting similar amounts (61,9%, 62,5%, 67,8%). The ethanolic extracts were evaluated for total phenolic compounds content and the leaf sample harvested in the Douro Litoral region was the one that presented the highest content (136,50 ± 14,54 mg EAG / g extract). All the ethanolic extracts showed antioxidant properties, with the Douro Litoral sample being the one that demonstrated better results in the different assayed methodologies, which is in good agreement with its higher phenolics content. As expected, the essential oils presented very low levels of total phenolic compounds (ranging from 0,97 ± 0,18 to 2,35 ± 0,18 mg GAE /g oil). Regarding the antimicrobial activity, the commercial essential oils and those extracted from the leaves presented bactericidal activity against all the studied microorganisms, with the exception of Pseudomona aeruginosa, with the fruit EO having a lower antimicrobial activity. In sum, eucalyptus can be a potential source of natural antimicrobials and antioxidants intereting to different industries.
Description
Keywords
Eucalyptus globulus Atividade antioxidante Atividade antimicrobiana