Metabolização da quercetina e produção de quercetina 2,3-dioxigenase por Beauverias bassianas isoladas da região Centro-Oeste do Brasil

• Autor(a) principal: COSTA, Eula Maria de Melo Barcelos
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000bxr1
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/1554
• topic: Beauveria bassiana; biotransformação microbiana; quercetina; quercetina 2,3-dioxigenase; variabilidade genética; 1. Fungos (Centro-Oeste) 2. Beauveria bassiana 3. Quercetina - Flavonóide 4. Quercetina 2,3-dioxigenase; Beauveria bassiana; microbial biotransformation; quercetin; quercetin 2,3-dioxygenase; genetic variability; CNPQ::CIENCIAS DA SAUDE

Considering the vast biotechnological applicability described for Beauveria bassiana, the versatility microbial biotransformation exhibits, the important biological activities attributed to the flavonoid quercetin, the therapeutic perspectives of its use, and the activity the enzyme quercetin 2,3-dioxygenase has on quercetin, we intended to evaluate quercetin biotransformation by B. bassiana ATCC 7159 and isolates of B. bassiana collected in the Midwestern Region of Brazil. The objectives of this study were: evaluate the potential of B. bassiana isolates and B. bassiana ATCC 7159 to produce metabolites of quercetin; investigate quercetin 2,3-dioxygenase production by the isolates and B. bassiana ATCC 7159; determine the genetic variability among the isolates of B. bassiana and establish possible correlations between molecular data and quercetin 2,3-dioxygenase production. All isolates and B. bassiana ATCC 7159 were capable of metabolizing quercetin and form compounds described in mammalian quercetin biotransformation studies and isolate IP 94 produced a higher number of metabolites compared with the others. B. bassiana ATCC 7159 and isolates IP 94, IP 98, IP 129, IP 147 produced methylated metabolites, while isolates IP 8, IP 11, and IP 94 produced glucuronidated metabolites. All the isolates produced sulphated metabolites and methylated and glucuronidated metabolites simultaneously and were capable to synthesize quercetin 2,3-dioxygenase. Quercetin 2,3-dioxygenase synthesis on PDSM, used in its biotransformation process was higher than on basic medium. B. bassiana ATCC 7159 and the isolates IP 11 and IP 132 presented the highest quercetin 2,3-dioxigenase activity, whereas the isolates IP 153 and IP 3a presented the lowest ones. Quercetin metabolites formation and quercetin 2,3-dioxygenase production were not correlated with the geographic origin of the isolates. Genetic variability analysis by RAPD allowed the separation of the isolates into three distinct groups and showed high genetic diversity among them; however, the RFLP-PCR of ITS region did not provide characteristic markers to differentiate the isolates. The ITS region sequencing confirmed the identity of the isolates as B. bassiana. The results obtained can lead to the following conclusions: B. bassiana constitutes an interesting alternative to the use of chemical methods and biological systems to produce quercetin metabolites, but is necessary to optimize the biotransformation process in order to obtain a more expressive amount of metabolites; B. bassiana is able to produce quercetin 2,3-dioxygenase, although more detailed studies are needed to explain its production pathway, regulation, and mechanism of action.