Lipidos macromoleculares estruturais das paredes celulares suberificadas da cortica de Quercus suber L

In this work, the structure and composition of suberin from Cork-oak (Quercus suber L.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) barks are studied. A technique was developed to de polymerize suberin, and to simultaneously analyse long-chain aliphatic monomers and glycerol. Identification of compounds was made by GC-MS. Quantitative analysis was made by GC-FID, with use of calibrated internal standards. Glycerol was shown to be one of the main monomers released from suberin, 14% in Cork-oak, 26% in Douglas-fir. The use of calibrated standards showed that #alpha#, #omega#-diacids, comparatively to #omega#-hydroxy acids, exist in bigger proportions than reported earlier. A partial depolymerization by CaO-catalyzed methanolysis was applied to both corks, solubilizing about 4% of the suberins. Ca. 30% of these mixtures were dimers of two types, monoacylglycerols of suberinic acids and feruloyil esters of - hydroxyacids. The mixtures were separated and quantified by GC-MS and dimers identified by interpretation of their mass spectra or after the synthesis of the compounds. These results led us to propose a glyceryl-based structure for suberin, with links to cork cell wall aromatics through the #omega#-hydroxy acids. The developing of a three dimensional suberin will be made by successive linking of glycerol - #alpha#, #omega# diacids - glycerolAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga