Electrochemical evaluation of lipophilic antioxidants from Iryanthera juruensis fruits (Myristicaceae)

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:16Z No. of bitstreams: 1 S0100-46702005000300002.pdf: 257186 bytes, checksum: 92fc2838ebf083b3f97d28e2b2f4350f (MD5) Made available in DSpace on 2013-08-22T18:49:16Z (GMT). No. of bitstreams: 1 S0100-46702005000300002.pdf: 257186 bytes, checksum: 92fc2838ebf083b3f97d28e2b2f4350f (MD5) Previous issue date: 2005-09-01 Made available in DSpace on 2013-09-30T19:39:32Z (GMT). No. of bitstreams: 2 S0100-46702005000300002.pdf: 257186 bytes, checksum: 92fc2838ebf083b3f97d28e2b2f4350f (MD5) S0100-46702005000300002.pdf.txt: 20819 bytes, checksum: 6d029d978c0bf3ef37c70c56c4fbd7d9 (MD5) Previous issue date: 2005-09-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:18:58Z No. of bitstreams: 2 S0100-46702005000300002.pdf: 257186 bytes, checksum: 92fc2838ebf083b3f97d28e2b2f4350f (MD5) S0100-46702005000300002.pdf.txt: 20819 bytes, checksum: 6d029d978c0bf3ef37c70c56c4fbd7d9 (MD5) Made available in DSpace on 2014-05-20T14:18:58Z (GMT). No. of bitstreams: 2 S0100-46702005000300002.pdf: 257186 bytes, checksum: 92fc2838ebf083b3f97d28e2b2f4350f (MD5) S0100-46702005000300002.pdf.txt: 20819 bytes, checksum: 6d029d978c0bf3ef37c70c56c4fbd7d9 (MD5) Previous issue date: 2005-09-01 Testes em placas de CCDC reveladas com solução de beta-caroteno mostraram a presença de duas substâncias com propriedades antioxidantes no extrato hexânico. Elas foram isoladas e identificadas como 3-metil-sargacromenol (1) and sargacromenol (2). O extrato hexânico forneceu ainda o ácido 3-metil-sargaquinóico (3) e o ácido sargaquinóico (4). O comportamento eletroquímico destas substâncias foi investigado em CH2Cl2/Bu4NBF4 sobre eletrodo de carbono vítreo. A oxidação do grupo fenólico nos tocotrienóis 1 and 2 é responsável por um pico anódico em potenciais de +0.23V e +0.32V, os quais são correlacionados com sua atividade antioxidante. O mecanismo de oxidação é comparado com o comportamento eletroquímico do antioxidante alfa-tocopherol. TLC autographic assays revealed in the hexane extract of Iryanthera juruensis (Myristicaceae) the presence of two compounds, with antioxidant properties towards beta-carotene. They were isolated and identified as 3-methyl-sargachromenol (1) and sargachromenol (2). Further investigation of the hexane extract led to isolations of 3-methyl-sargaquinoic acid (3) and sargaquinoic acid (4). The electrochemical behaviour of these compounds was studied in CH2Cl2/Bu4NBF4 at glassy carbon electrode. The phenolic group in both tocotrienols 1 and 2 are oxidized at +0.23V and +0.32V and their oxidation potentials are correlated with the observed antioxidant activities and oxidation mechanism of alpha-tocopherol. The reductive voltametric behaviour of quinone function in both plastoquinones 3 and 4 is discussed. Universidade Estadual Paulista Instituto de Química Universidade Estadual Paulista Instituto de Química