resumo
The chemical composition of the lipohilic extracts of the inner and outer barks of Eucalyptus grandis x globulus, cultivated in Portugal, was studied by gas chromatography-mass spectrometry. The two bark fractions show different chemical compositions. beta-Sitosterol is the most abundant compound in the inner bark (82 mg kg(-1)), while long chain aliphatic alcohols are the main family of components accounting for 208 mg kg(-1). In the outer bark fraction, triterpenic compounds (8.5 g kg(-1)) are the most abundant ones from which methyl morolate (methyl 3-hydroxyolean-18-en-28-oate) is the chief component (3 g kg(-1)). This oleanane type tritepenic acid methyl ester was identified here for the first time as a component of Eucalyptus bark tissues using GC-MS and NMR. Other high value triterpenic acids such as ursolic, oleanolic and betulinic acids, accounting for 1.3, 0.9 and 0.6 g kg(-1), respectively, were also detected in this fraction. Finally, the extraction of methyl morolate with supercritical CO2 was also carried out aiming at designing an environmentally friendly extraction alternative for this abundant compound. At 20 MPa and 333K, the methyl morolate extraction attained a plateau at 6h. In the whole, the acetylated triterpenic acids were more significantly extracted when compared to their free acids, which is directly related with the less polar nature of the former molecules. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
CHROMATOGRAPHY-MASS SPECTROMETRY; VALUE TRITERPENIC COMPOUNDS; MORONIC ACID-DERIVATIVES; ANTI-AIDS AGENTS; FLUID EXTRACTION; URSOLIC ACID; PENTACYCLIC TRITERPENES; CHEMICAL-COMPOSITION; GAS-CHROMATOGRAPHY; OLEANOLIC ACID
categoria
Agriculture
autores
Patinha, DJS; Domingues, RMA; Villaverde, JJ; Silva, AMS; Silva, CM; Freire, CSR; Neto, CP; Silvestre, AJD
nossos autores
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Manuel Silva
Professor associado
Carlos Pascoal Neto
Diretor do Raiz
Carmen Sofia da Rocha Freire Barros
Investigador Coordenadoragradecimentos
We acknowledge the 7th Framework Programme FP7/2007-2013, for funding project AFORE: Forest biorefineries: added-value from chemicals and polymers by new integrated separation, fractionation and upgrading technologies (CP-IP 228589-2), to the BIIPP project (QREN 11551) for the awarding of a PhD grant, to CICECO (Pest-C/CTM/LA0011/2011) and to QOPNA (PEst-C/QUI/UI0062/2011).