RESUMO
Volatile oils (VOs) obtained from the aerial parts of species from the Disynaphiinae subtribe (genera Acanthostyles, Campovassouria, Disynaphia, Grazielia, Raulinoreitzia, and Symphyopappus) of Eupatorieae (Asteraceae) collected in Rio Grande do Sul, southern Brazil, were characterized using GC-MS. The yield of VOs relative to fresh material ranged from 0.2 to 1.7% between the Disynaphiinae subtribe samples (Acanthostyles buniifolius, Campovassouria cruciata, Disynaphia ericoides, D. ligulifolia, D. spathulata, Symphyopappus casarettoi, S. reticulatus, S. itatiayensis, Grazielia gaudichaudieana, G. intermedia, G. nummularia, G. serrata, Raulinoreitzia crenulata, and R. tremula). The VOs in this subtribe were mainly composed of terpene compounds. Compositional multivariate analysis demonstrated clustering between the samples of Grazielia and Raulinoreitzia on one side, which contain relatively higher proportions of monoterpenes, and Disynaphia and Campovassouria, which contain more oxygenated sesquiterpenes. The samples of Symphyopappus and Acanthostyles, which contain more sesquiterpene hydrocarbons, were located between these two main groups. Multivariate analysis accounting for the recent proposals of subtribal recircumscription of Eupatorieae was also performed. The odd chemistry of S. itatiayensis was in accordance with the recent attempts to exclude it from the genus Symphyopappus.
Assuntos
Asteraceae , Óleos Voláteis , Sesquiterpenos , Brasil , Análise MultivariadaRESUMO
Investigating the influence of seasonal variations on biological activities is important for pharmacological studies and metabolic engineering. Therefore, this study was conducted to determine the variation of the chemical composition of essential oils obtained from Nectandra megapotamica leaves, collected at different stages of plant development, as well as its influence on the biological activities. A total of 38 compounds were identified that accounted for 97â»99.2% of the chemical composition of the oils. Major differences were observed in the monoterpenic fraction, representing 5.1% of the compounds identified in the productive rest phase to 37.1% in the blooming phase. Bicyclogermacrene and germacrene D were the predominant compounds identified in the oil of all collections. Furthermore, limonene, ß-pinene, and spathulenol were identified predominantly in the samples of blooming and fruiting phases. The oils exhibited significant antichemotactic activity and different effects in scavenging the radical 2,2-diphenyl-1-picrylhydrazyl. Variations were also observed in the antifungal activity, with the minimum inhibitory concentrations ranging from 125 to 500 µg/mL. These results demonstrate the influence of monoterpenes, primarily limonene, α-pinene, and ß-pinene, on the bioactivities of the oil. Studies investigating the variations in the chemical composition of essential oil may offer a strategy to produce a compound or a group of compounds of interest to industries with a specific pharmacological focus.
Assuntos
Antifúngicos/farmacologia , Antioxidantes/farmacologia , Fungos/efeitos dos fármacos , Lauraceae/química , Monoterpenos/farmacologia , Óleos Voláteis/química , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Compostos de Bifenilo/antagonistas & inibidores , Relação Dose-Resposta a Droga , Engenharia Metabólica , Testes de Sensibilidade Microbiana , Monoterpenos/química , Óleos Voláteis/isolamento & purificação , Picratos/antagonistas & inibidores , Relação Estrutura-AtividadeRESUMO
Eupatorium tremulum is a South American shrub reported to cause cattle digestive intoxication, of which the volatile oil, mainly composed by bisabolane- and amorphane-type sesquiterpenoids, exhibits high quantitative variability. This report describes the application of chemometric tools for the identification of volatile compounds that characterize phenophasical changes in the plant. Preblooming, blooming, and postblooming specimens were paired-sampled and submitted to hydrodistillation and GC-MS analysis. Differential results were analyzed by orthogonal projection to latent structures-discriminant analysis (OPLS-DA), and the substances with different distribution in each phase were highlighted. Mean results between phases were submitted to factor analysis (FA), and correlations between the variables were demonstrated. Preblooming to blooming phase change was characterized by decreased levels of amorpha-4-en-7-ol (13) and epi-α-bisabolol (19) and increased amounts of amorpha-4,7(11)-diene (1). Blooming to postblooming change was characterized by decreases in 1, germacrene D (2), and ß-bisabolene (4) and increases in 13 and 19. Finally, enhanced levels of 1, 4, and 2 reflected the change from the postblooming to the preblooming phase. FA revealed a strong correlation in the variability between the bisabolane hydrocarbons, possibly related to its common enzymatic origin. Another strong source of negative correlation showed bisabolane- and amorphane-type alcohols, on one side, and amorphane-type furans, on the other side, to occur in two alternative oxidation routes. Finally, 1 was strongly negatively correlated to its oxidized furan and ketofuran derivatives [verboccidentafuran (16) and 3-oxo-verboccidentafuran (23)] and additionally to a third compound, putatively identified as a biosynthetic intermediate between this hydrocarbon and the furans, amorpha-4,7(11)-dien-8-one (20).