2,6-Disubstituted 7-(naphthalen-2-ylmethyl)-7H-purines as a new class of potent antitubercular agents inhibiting DprE1.

Phenotypic screening of an in-house library of small molecule purine derivatives against Mycobacterium tuberculosis (Mtb) led to the identification of 2-morpholino-7-(naphthalen-2-ylmethyl)-1,7-dihydro-6H-purin-6-one 10 as a potent antimycobacterial agent with MIC99 of 4 µM. Thorough structure-activity relationship studies revealed the importance of 7-(naphthalen-2-ylmethyl) substitution for antimycobacterial activity, yet opened the possibility of structural modifications at positions 2 and 6 of the purine core. As the result, optimized analogues with 6-amino or ethylamino substitution 56 and 64, respectively, were developed. These compounds showed strong in vitro antimycobacterial activity with MIC of 1 µM against Mtb H37Rv and against several clinically isolated drug-resistant strains, had limited toxicity to mammalian cell lines, medium clearance with respect to phase I metabolic deactivation (27 and 16.8 µL/min/mg), sufficient aqueous solubility (>90 µM) and high plasma stability. Interestingly, investigated purines, including compounds 56 and 64, lacked activity against a panel of Gram-negative and Gram-positive bacterial strains, indicating a specific mycobacterial molecular target. To investigate the mechanism of action, Mtb mutants resistant to hit compound 10 were isolated and their genomes were sequenced. Mutations were found in dprE1 (Rv3790), which encodes decaprenylphosphoryl-ß-d-ribose oxidase DprE1, enzyme essential for the biosynthesis of arabinose, a vital component of the mycobacterial cell wall. Inhibition of DprE1 by 2,6-disubstituted 7-(naphthalen-2-ylmethyl)-7H-purines was proved using radiolabelling experiments in Mtb H37Rv in vitro. Finally, structure-binding relationships between selected purines and DprE1 using molecular modeling studies in tandem with molecular dynamic simulations revealed the key structural features for effective drug-target interaction.

Global distribution of functionally important CYP2C9 alleles and their inferred metabolic consequences.

BACKGROUND: Genetic variability in the cytochrome P450 CYP2C9 constitutes an important predictor for efficacy and safety of various commonly prescribed drugs, including coumarin anticoagulants, phenytoin and multiple non-steroidal anti-inflammatory drugs (NSAIDs). A global map of CYP2C9 variability and its inferred functional consequences has been lacking. RESULTS: Frequencies of eight functionally relevant CYP2C9 alleles (*2, *3, *5, *6, *8, *11, *13 and *14) were analyzed. In total, 108 original articles were identified that included genotype data from a total of 81,662 unrelated individuals across 70 countries and 40 unique ethnic groups. The results revealed that CYP2C9*2 was most abundant in Europe and the Middle East, whereas CYP2C9*3 was the main reason for reduced CYP2C9 activity across South Asia. Our data show extensive variation within superpopulations with up to tenfold differences between geographically adjacent populations in Malaysia, Thailand and Vietnam. Translation of genetic CYP2C9 variability into functional consequences indicates that up to 40% of patients in Southern Europe and the Middle East might benefit from warfarin and phenytoin dose reductions, while 3% of patients in Southern Europe and Israel are recommended to reduce starting doses of NSAIDs. CONCLUSIONS: This study provides a comprehensive map of the genetic and functional variability of CYP2C9 with high ethnogeographic resolution. The presented data can serve as a useful resource for CYP2C9 allele and phenotype frequencies and might guide the optimization of genotyping strategies, particularly for indigenous and founder populations with distinct genetic profiles.