Síntese, caracterização e atividade antifúngica de derivados anfifílicos de dietilaminoetil-quitosana contra Aspergillus flavus e Aspergillus parasiticus
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Data
2013-01-25
Autores
Gabriel, Juliana dos Santos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
No presente trabalho foi realizada a síntese e caracterização de derivados de quitosana que tiveram suas atividades antifúngicas testadas contra os fungos Aspergillus flavus e A. parasiticus. As quitosanas utilizadas nas sínteses foram obtidas da desacetilação heterogênea de quitosana comercial e da quitosana comercial de média massa molecular. Os graus médios de desacetilação ( ) da quitosana desacetilada (CH) e da quitosana de média massa molecular desacetilada (CHm) foram determinados pelas técnicas de Potenciometria e Espectroscopia de Ressonância Magnética Nuclear de Hidrogênio (RMN-H). Parte da quitosana desacetilada CH foi degradada para obtenção de polímeros de baixa massa molecular (CHD). As massas moleculares médias das quitosanas CHm, CH e CHD foram determinadas por viscosimetria e os valores obtidos foram 42,93 kDa, 15,22 kDa e 610,79 Da, respectivamente. Os derivados hidrofílicos foram obtidos pela reação das quitosanas CHm, CH e CHD com cloreto de 2-cloro-N,N-dietilaminoetila (DEAE). Os graus de substituição (GS) de grupos DEAE de CHm, CH e CHD foram determinados utilizando-se RMN-H e os valores obtidos foram 14, 30 e 43%, respectivamente. Na sequência, as quitosanas CHm14DEAE, CH30DEAE e CHD43DEAE foram alquiladas com dodecil aldeído seguido pela redução com cianoboroidreto de sódio, obtendo-se derivados com diferentes graus de substituição. Os graus de substituição por grupos dodecila (GDD) para a quitosana contendo 14% de grupos DEAE foram 2,5, 10 e 14%. Para a quitosana com 30% de DEAE os graus de substituição por dodecila foram 2,7, 10 e 19%. Para o derivado contendo 43% de DEAE os graus de substituição por dodecila foram 5, 28 e 39%. Além da Espectroscopia de RMN-H o sucesso da obtenção dos derivados anfifílicos também foi indicado por meio da...
In this study, it was done the synthesis and characterization of chitosan derivatives, that had their antifungal activity tested against Aspergillus flavus and A. parasiticus. The chitosan used for the syntheses was obtained from heterogeneous deacetylation of the commercial chitosan and commercial chitosan of average molecular mass. The average degrees of deacetylation ( ) of chitosan (CH) and deacetylated chitosan of medium molecular weight (CHm) were determined by Potentiometry and techniques Spectroscopy Hydrogen Nuclear Magnetic Resonance (H-NMR). Part of deacetylated chitosan CH was degraded to obtain low molecular weight polymers (CHD). The average molecular weights of chitosans CHm, CH and CHD were determined by viscometry, and the values obtained were 42.93 kDa, 15.22 kDa and 610.79 Da, respectively. Hydrophilic derivatives were obtained by reaction of chitosan CHm, CH, CHD with chloride 2-chloro-N,N-diethylaminoethyl (DEAE). The degrees of substitution (DS) by DEAE groups of CHm, CH and CHD were determined by H-NMR and the values obtained were 14, 30 and 43%, respectively. After that the chitosans CHm14DEAE, CH30DEAE and CHD43DEAE were alkylated with dodecyl aldehyde followed by reduction with sodium cyanoborohydride to yield derivatives with different degrees of substitution. The degrees of substitution by dodecyl groups (GDD) for the chitosan containing 14% of DEAE groups were 2.5, 10 and 14%. For chitosan with 30% of DEAE the degrees of substitution by dodecyl groups were 2.7, 10... (Complete abstract click electronic access below)
In this study, it was done the synthesis and characterization of chitosan derivatives, that had their antifungal activity tested against Aspergillus flavus and A. parasiticus. The chitosan used for the syntheses was obtained from heterogeneous deacetylation of the commercial chitosan and commercial chitosan of average molecular mass. The average degrees of deacetylation ( ) of chitosan (CH) and deacetylated chitosan of medium molecular weight (CHm) were determined by Potentiometry and techniques Spectroscopy Hydrogen Nuclear Magnetic Resonance (H-NMR). Part of deacetylated chitosan CH was degraded to obtain low molecular weight polymers (CHD). The average molecular weights of chitosans CHm, CH and CHD were determined by viscometry, and the values obtained were 42.93 kDa, 15.22 kDa and 610.79 Da, respectively. Hydrophilic derivatives were obtained by reaction of chitosan CHm, CH, CHD with chloride 2-chloro-N,N-diethylaminoethyl (DEAE). The degrees of substitution (DS) by DEAE groups of CHm, CH and CHD were determined by H-NMR and the values obtained were 14, 30 and 43%, respectively. After that the chitosans CHm14DEAE, CH30DEAE and CHD43DEAE were alkylated with dodecyl aldehyde followed by reduction with sodium cyanoborohydride to yield derivatives with different degrees of substitution. The degrees of substitution by dodecyl groups (GDD) for the chitosan containing 14% of DEAE groups were 2.5, 10 and 14%. For chitosan with 30% of DEAE the degrees of substitution by dodecyl groups were 2.7, 10... (Complete abstract click electronic access below)
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Palavras-chave
Quitosana, Quitina, Fungicidas, Aspergillus, Polissacarideos, Chitosan
Como citar
GABRIEL, Juliana dos Santos. Síntese, caracterização e atividade antifúngica de derivados anfifílicos de dietilaminoetil-quitosana contra Aspergillus flavus e Aspergillus parasiticus. 2013. 102 f. Dissertação (mestrado) - Universidade Estadual Paulista Julio de Mesquita Filho. Instituto de Biociências, Letras e Ciências Exatas, 2013.