RESUMO
Lisofylline (LSF) is a drug candidate that has been under investigation for acute respiratory distress syndrome, acute lung injury, septic shock and mucositis. As LSF is not commercially available in our country, we produced it for pharmacokinetic studies. In the present work whole-cell reduction of pentoxifylline [1-(5-oxohexyl)-3,5-dimethylxanthine] to LSF [1-(5R-hydroxyhexyl)-3,5-dimethylxanthine] using Lactobacillus kefiri DSM 20587 was investigated. Glucose or 2-propanol was used as a co-substrate to regenerate the NADPH cofactor. The reaction conditions were optimized. The influence of different concentrations of co-substrates on the yield and enantioselectivity of the biotransformation of pentoxifylline into LSF were tested. Maximum yield (100%) of biotransformation was reached in the presence of glucose as a co-substrate. At glucose concentrations of 675 and 900 mM the bioreduction of pentoxifylline proceeded highly enantioselectively (enantiomeric excess for the R enantiomer of 98%).
Assuntos
2-Propanol/metabolismo , Reatores Biológicos/microbiologia , Glucose/metabolismo , Lactobacillus/metabolismo , Pentoxifilina/análogos & derivados , Pentoxifilina/metabolismo , Biotransformação , Técnicas de Cultura de Células/métodos , Lactobacillus/crescimento & desenvolvimento , Oxirredução , Pentoxifilina/química , EstereoisomerismoRESUMO
Praziquantel (PZQ) is the drug of choice for the treatment of human schistosomiasis. It is estimated that about 200 million people in the world are currently affected by this tropical disease. Now PZQ is also used in malaria treatment. The usefulness of PZQ as antimalarial drug is important because of rapid development of resistance to usually applied drugs. PZQ undergoes extensive metabolism in human body, mainly in liver by two cytochrome P-450 isoenzymes 2B1 and 3A. As the result of these biotransformations numerous mono- and dihydroxylated derivatives in B, C and D ring are formed. Two metabolites have been fully identified and described, as cis- and trans-4-hydroxypraziquantel. Up to now there were created many different in vitro and in vivo models of PZQ biotransformations. In vitro model of PZQ biotransformation was created by using human cytochrome P-450 3A4 expressed in Eschelichia coli and Saccharomyces cerevisiae. In the first experiment we have used human cytochrome P-450 3A4 from Escherichia coli (isolated on NTA-column). In the second experiment microsomes isolated from Saccharomyces cerevisiae containing coexpressed human CYP 3A4, human CYP-reductase and human cytochrome b5 were used. The reactions were monitored by HPLC and MS.
Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Praziquantel/farmacocinética , Anti-Helmínticos , Antimaláricos , Biotransformação , Citocromo P-450 CYP3A , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/isolamento & purificação , Citocromos b5 , Escherichia coli/genética , Humanos , Microssomos/metabolismo , NADPH-Ferri-Hemoproteína Redutase , Saccharomyces cerevisiae/genética , Transdução GenéticaRESUMO
Praziquantel (PZQ), a broad spectrum antihelmintic drug, is extensively metabolized in the liver, yielding mainly monohydroxylated and dihydroxylated phase-I-metabolites. However, the exact chemical structures of the most metabolites are still unknown. In the presented research, three types of PZQ biotransformations were performed: biotransformation with the whole cells of Saccharomyces cerevisiae, with cytochrome c from Saccharomyces cerevisiae and with microsomes isolated from Saccharomyces cerevisiae. To describe the obtained metabolites TLC, RP-TLC, and HPLC were used.
