Folate-Synthesizing Enzyme System as Target for Development of Inhibitors and Inhibitor Combinations against Candida albicansSynthesis and Biological Activity of New 2,4-Diaminopyrimidines and 4‘-Substituted 4-Aminodiphenyl Sulfones
摘要:
The paper describes the design, synthesis, and testing of inhibitors of folate-synthesizing enzymes and of whole cell cultures of Candida albicans. The target enzymes used were dihydropteroic acid synthase (SYN) and dihydrofolate reductase (DHFR). Several series of new 2,4-diaminopyrimidines were synthesized and tested as inhibitors of DHFR and compared with their activity against DHFR derived from mycobacteria and Escherichia coli. To test for selectivity, also rat DHFR was used. A series of substituted 4-aminodiphenyl sulfones was tested for inhibitory activity against SYN and the I-50 values compared to those obtained previously against Plasmodium berghei- and E. coli-derived SYN. Surprisingly, QSAR equations show very similar structural dependencies. To find an explanation for the large difference in the I-50 values observed for enzyme inhibition (SYN, DHFR) and for inhibition of cell cultures of Candida, mutant strains with overexpressed efflux pumps and strains in which such pumps are deleted were included in the study and the MICs compared. Efflux pumps were responsible for the low activity of some of the tested derivatives, others showed no increase in activity after pumps were knocked out. In this case it may be speculated that these derivatives are not able to enter the cells.
Folate-Synthesizing Enzyme System as Target for Development of Inhibitors and Inhibitor Combinations against Candida albicansSynthesis and Biological Activity of New 2,4-Diaminopyrimidines and 4‘-Substituted 4-Aminodiphenyl Sulfones
摘要:
The paper describes the design, synthesis, and testing of inhibitors of folate-synthesizing enzymes and of whole cell cultures of Candida albicans. The target enzymes used were dihydropteroic acid synthase (SYN) and dihydrofolate reductase (DHFR). Several series of new 2,4-diaminopyrimidines were synthesized and tested as inhibitors of DHFR and compared with their activity against DHFR derived from mycobacteria and Escherichia coli. To test for selectivity, also rat DHFR was used. A series of substituted 4-aminodiphenyl sulfones was tested for inhibitory activity against SYN and the I-50 values compared to those obtained previously against Plasmodium berghei- and E. coli-derived SYN. Surprisingly, QSAR equations show very similar structural dependencies. To find an explanation for the large difference in the I-50 values observed for enzyme inhibition (SYN, DHFR) and for inhibition of cell cultures of Candida, mutant strains with overexpressed efflux pumps and strains in which such pumps are deleted were included in the study and the MICs compared. Efflux pumps were responsible for the low activity of some of the tested derivatives, others showed no increase in activity after pumps were knocked out. In this case it may be speculated that these derivatives are not able to enter the cells.
Compounds of the formula ##STR1## and pharmaceutically acceptable salts thereof and antimalarial and antibacterial compositions containing an effective amount of active agent and a pharmaceutically acceptable carrier particularly in oral dosage form wherein R is hydrogen, methyl or ethyl; X is alkylene of 1-10 carbon atoms; Y is oxygen, sulphur or a bond, and Ar is an optionally substituted aryl moiety; are useful for their antimalarial and antibacterial activity.
Folate-Synthesizing Enzyme System as Target for Development of Inhibitors and Inhibitor Combinations against <i>Candida </i><i>a</i><i>lbicans</i>Synthesis and Biological Activity of New 2,4-Diaminopyrimidines and 4‘-Substituted 4-Aminodiphenyl Sulfones
作者:Thomas Otzen、Ellen G. Wempe、Brigitte Kunz、Rainer Bartels、Gudrun Lehwark-Yvetot、Wolfram Hänsel、Klaus-Jürgen Schaper、Joachim K. Seydel
DOI:10.1021/jm030931w
日期:2004.1.1
The paper describes the design, synthesis, and testing of inhibitors of folate-synthesizing enzymes and of whole cell cultures of Candida albicans. The target enzymes used were dihydropteroic acid synthase (SYN) and dihydrofolate reductase (DHFR). Several series of new 2,4-diaminopyrimidines were synthesized and tested as inhibitors of DHFR and compared with their activity against DHFR derived from mycobacteria and Escherichia coli. To test for selectivity, also rat DHFR was used. A series of substituted 4-aminodiphenyl sulfones was tested for inhibitory activity against SYN and the I-50 values compared to those obtained previously against Plasmodium berghei- and E. coli-derived SYN. Surprisingly, QSAR equations show very similar structural dependencies. To find an explanation for the large difference in the I-50 values observed for enzyme inhibition (SYN, DHFR) and for inhibition of cell cultures of Candida, mutant strains with overexpressed efflux pumps and strains in which such pumps are deleted were included in the study and the MICs compared. Efflux pumps were responsible for the low activity of some of the tested derivatives, others showed no increase in activity after pumps were knocked out. In this case it may be speculated that these derivatives are not able to enter the cells.