Linear aliphatic dimeric esters from cork suberin.
Cork suberin was partially depolymerized by methanolysis catalyzed by calcium hydroxide. Analysis by GC-MS of the methanolysate showed suberin monomers, including glycerol and long-chain alpha,omega-diacids and omega-hydroxyacids. ESI-MS analysis of the methanolysate showed, besides the aliphatic monomers, suberin oligomers, including linear dimeric esters of alpha,omega-diacids and omega-hydroxyacids. Two types of dimeric esters were identified: a alpha,omega-diacid linked to a omega-hydroxyacid and two inter-linked omega-hydroxyacids. The alpha,omega-diacids and omega-hydroxyacids found as monomer residues in the dimeric esters were mainly the C18 monomers with midchain substituents. The identification of these dimeric esters was based in their CID-MS/MS spectra and confirmed after synthesis of model compounds. The occurrence of inter-esterified long-chain monomers in suberin brings a new insight in the understanding of the polyester structure of this biopolymer.
Graça
José
J
Instituto Superior de Agronomia, Departamento de Engenharia Florestal, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal. jograca@isa.utl.pt
Santos
Sara
S
D019281:Dimerization; D004952:Esters / Q000737:chemistry*; D008055:Lipids; D008563:Membrane Lipids / Q000737:chemistry*; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014197:Trees / Q000737:chemistry*
D004952:Esters; D008055:Lipids; D008563:Membrane Lipids; C065875:suberin