What is ethyl propionate

DC FieldValueLanguagedc.contributor.advisorKroh, Lothar W.endc.contributor.authorArnold, Verenaendc.date.accessioned2015-11-20T16: 36: 32Z-dc.date.available2005-11-08T12: 00: 00Z-dc.date.issued2005-11-08-dc.date.submitted2005-11-08-dc.identifier.uriurn: nbn: de: kobv: 83-opus-11430-dc.identifier.urihttp://depositonce.tu-berlin.de/handle/11303/1528-dc.identifier.urihttp://dx.doi.org/10.14279/depositonce-1231-dc.description.abstractThe hydrolyzability of carboxylic acid esters, which are important as flavorings and as components of food packaging material, plays an important role in the toxicological evaluation of these substances. The aim of the study was to derive structure-activity relationships from the enzymatic hydrolysis of carboxylic acid esters in biological material. 15 esters with characteristic structural features relevant to flavorings were selected: ethyl esters with linear, unbranched acyl radicals of various chain lengths (ethyl propionate, valerate, heptanoate, undecanoate and myristate), ethyl and benzyl esters with branched and aromatic acyl or alkyl radicals (ethyl isovalerate , Ethyl and benzyl tiglate, ethyl and benzyl phenyl acetate, benzyl salicylate and ethyl cinnamate) as well as esters with the same empirical formula and different chemical structure (methyl octanoate, ethyl heptanoate and isoamyl butyrate) The prerequisite for the metabolism of a substance is its distribution in the body. In the first phase of the project, the solubility properties of the esters were assessed. Based on the solubility in connection with the calculated octanol / water partition coefficient, the hydrophobic properties of the esters investigated could be described. Rat plasma hydrolyzed the esters by a factor of 7 to 10 (ethyl tiglate) and 34 to 51 (benzyl tiglate) faster than human plasma. The highest hydrolysis activity was found in rat liver homogenate, which hydrolyzed ethyl and benzyl tiglate 600 times and 350 times faster than rat plasma. Ethyl undecanoate, myristate and cinnamate as well as benzyl salicylate and tiglate were slowly degraded in human plasma. In connection with their hydrophobic properties, it must be assumed that these substances can circulate in the body and thus there is a tendency to accumulate. The esters were divided into three classes, with the half-life and quotient of maximum velocity and Michaelis-Menten constant being used as criteria for hydrolyzability in human blood plasma: rapid hydrolyzability (ethyl valerate, isoamyl butyrate, benzylphenyl acetate, phenyl acetate (reference substance)), moderate hydrolyzability Ethyl heptanoate, ethyl isovalerate, ethyl phenyl acetate) and slow hydrolyzability (ethyl undecanoate, ethyl myristate, ethyl tiglate, benzyl tiglate, ethyl cinnamate, benzyl salicylate). The different structural properties showed that, in principle, rapid hydrolysis of carboxylic acid esters in human blood plasma cannot be assumed. The possibility of slow hydrolysis must be expected if substances with voluminous substituents are found in the vicinity of the sp2-hybridized carbonyl oxygen atom (alpha position). These include in particular: acyl chain lengths with more than 4 carbon atoms, iso-, sec- or tert-functions, aromatic rings with polar groups such as 2-hydroxy groups and trans double bonds.dedc.description.abstractCarboxylic acid esters are flavoring substances used in foodstuffs or food contact material. The hydrolysis of carboxylic esters is very important for their toxicological evaluation. The study describes the structure-activity effects of the enzymatic hydrolysis of carboxylic esters in biological substances. 15 substances with characteristic chemical structures of flavors or substances in food contact materials were chosen: ethyl ester with various linear acylic residues of various length (ethyl propionate, -valerate, -heptanoate, undcanoate and myristate), ethyl and benzyl esters with different branched or aromatic acyl residues (ethyl isovalerate, ethyl and benzyl tiglate, phenylacetate, benzyl salicylate and ethyl cinnamate) and isomeric substances (methyl octanoate, ethyl heptanoate and isoamyl butyrate). In order to be metabolized a substance has to be distributed throughout the organism. At first, we determine the solubility of the esters and their hydrophobic properties by calculating the octanol-water coefficient. Ester were hydrolyzed 10 - 51 times faster in rat plasma than in human plasma. The rate of hydrolysis of rat liver homogenat was 350 - 600 times faster than rat plasma. We determine a very slow hydrolysis in human plasma of ethyl undecanoate, myristate, cinnamate and benzyl salicylate and tiglate. Therefore, circulation of these substances and accumulation in the body are possible. The esters were classified by their hydrolysis rates in human plasma: fast hydrolysis (ethyl valerate, isoamyl butyrate, benzyl phenylacetate), moderate hydrolysis (ethyl propionate, heptanoate, isovalerate, phenylacetate) and slow hydrolysis (ethyl undecanoate, myristate, tiglate, cinnamate, benzyl tiglate and salicylate). By the following functional groups a slow hydrolysis rate in human plasma can be estimate: voluminous functional groups near the sp┬▓ hybridized carbonyl oxygen atom (alpha-position), straight-chain aliphatic saturated primary acyl residues, iso- sec- or tert-alcohol residues, aromatic residues with polar functional groups (2-hydroxy-residue) and trans-double bonds.endc.languageGermanendc.language.isodeendc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/endc.subject.ddc540 Chemistry and Associated Sciencesendc.subject.otherFlavoringsdedc.subject.otherCarboxylic acid esterdedc.subject.otherEnzymesdedc.subject.otherhydrolysisdedc.subject.otherStructure-activity relationshipsdedc.subject.otherCarboxylic acid esterendc.subject.otherEnzymesendc.subject.otherFlavoring agentsendc.subject.otherHydrolysisendc.subject.otherStructure-function relationshipendc.titleStructure-activity relationships in the enzymatic hydrolysis of carboxylic acid estersdedc.typeDoctoral thesisentub.accessrights.dnbfree*tub.publisher.universityorinstitutionTechnical University Berlinendc.contributor.grantorTechnical University of Berlin, Faculty III - Process Sciencesendc.date.accepted2005-07-11-dc.title.translatedStructure-function relationship between different types of carboxylic acid esters and their rates of enzymatic hydrolysisendc.type.versionpublishedVersionentub.identifier.opus31143-tub.identifier.opus41138-Appears in Collections:Inst. 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