title: Evaluation of 7-arylaminopyrazolo[1,5-a]pyrimidines as anti-Plasmodium falciparum, antimalarial, and Pf-dihydroorotate dehydrogenase inhibitors.
abstract: Malaria remains one of the most serious global infectious diseases. An important target for antimalarial chemotherapy is the enzyme dihydroorotate dehydrogenase from Plasmodium falciparum (PfDHODH), which is responsible for the conversion of dihydroorotate to orotate in the de novo pyrimidine biosynthetic pathway. In this study, we have designed and synthesized fifteen 7-arylpyrazolo[1,5-a]pyrimidine derivatives using ring bioisosteric replacement and molecular hybridization of functional groups based on the highly active 5-methyl-N-(naphthalen-2-yl)-2-(trifluoromethyl)- [1,2,4]triazolo[1,5-a]pyrimidin-7-amine. The compounds were tested against Plasmodium falciparum, as antimalarials in mice with P. berghei, and as inhibitors of PfDHODH. Thirteen compounds were found to be active against P. falciparum, with IC50values ranging from 1.2 ± 0.3 to 92 ± 26 μM in the anti-HRP2 and hypoxanthine assays. Four compounds showed the highest selective index (SI), which is a ratio between cytotoxicity and activity in vitro. The inhibition of PfDHODH showed that compound 30 (R2= CH3; R5= CF3; Ar = 7-β-naphthyl) displayed higher and selective inhibitory activity, with IC50= 0.16 ± 0.01 μM, followed by 25 (R2= CH3; R5= CH3; Ar = 7-β-Naphthyl) and 19 (R2= CF3; R5= CF3; Ar = 7-β-naphthyl), with IC50= 4 ± 1 μM and 6 ± 1 μM, respectively. The trifluoromethyl group at the 2- or 5-positions of the pyrazolo[1,5-a]pyrimidine ring led to increased drug activity. The docking results agreed with the values obtained from enzymatic assays.
authors.affiliation: Departamento de Síntese de Fármacos, Instituto de Tecnologia em Fármacos, Farmanguinhos-FIOCRUZ, Rua Sizenando Nabuco 100, Manguinhos, Rio de Janeiro, RJ 21041-250, Brazil; Programa de Pós Graduação em Química, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Luís Felipe S P
authors.initials: LFSP
authors.lastname: Azeredo
authors.affiliation: Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ, Belo Horizonte, MG 30190-002, Brazil; Programa de Pós Graduação em Medicina Molecular, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Julia P
authors.initials: JP
authors.lastname: Coutinho
authors.affiliation: Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n Monte Alegre, 14040-903 Ribeirão Preto, SP, Brazil.
authors.forename: Valquiria A P
authors.initials: VAP
authors.lastname: Jabor
authors.affiliation: Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n Monte Alegre, 14040-903 Ribeirão Preto, SP, Brazil.
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Feliciano
authors.affiliation: Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n Monte Alegre, 14040-903 Ribeirão Preto, SP, Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Nonato
authors.affiliation: Programa de Pós Graduação em Química, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Kaiser
authors.affiliation: Departamento de Síntese de Fármacos, Instituto de Tecnologia em Fármacos, Farmanguinhos-FIOCRUZ, Rua Sizenando Nabuco 100, Manguinhos, Rio de Janeiro, RJ 21041-250, Brazil.
authors.forename: Carla Maria S
authors.initials: CMS
authors.lastname: Menezes
authors.affiliation: Grupo de Biofísica Computacional e Modelagem Molecular, Programa de Computação Científica (PROCC), FIOCRUZ, Av. Brasil 4365, Rio de Janeiro, CEP 21040-360, Brazil.
authors.forename: Amanda S O
authors.initials: ASO
authors.lastname: Hammes
authors.affiliation: Grupo de Biofísica Computacional e Modelagem Molecular, Programa de Computação Científica (PROCC), FIOCRUZ, Av. Brasil 4365, Rio de Janeiro, CEP 21040-360, Brazil.
authors.forename: Ernesto Raul
authors.initials: ER
authors.lastname: Caffarena
authors.affiliation: Departamento de Síntese de Fármacos, Instituto de Tecnologia em Fármacos, Farmanguinhos-FIOCRUZ, Rua Sizenando Nabuco 100, Manguinhos, Rio de Janeiro, RJ 21041-250, Brazil.
authors.forename: Lucas V B
authors.initials: LVB
authors.lastname: Hoelz
authors.affiliation: Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ, Belo Horizonte, MG 30190-002, Brazil.
authors.forename: Nicolli B
authors.initials: NB
authors.lastname: de Souza
authors.affiliation: Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ, Belo Horizonte, MG 30190-002, Brazil.
authors.forename: Glaécia A N
authors.initials: GAN
authors.lastname: Pereira
authors.affiliation: Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ, Belo Horizonte, MG 30190-002, Brazil.
authors.forename: Isabela P
authors.initials: IP
authors.lastname: Cerávolo
authors.affiliation: Centro de Pesquisas René Rachou, CPqRR-FIOCRUZ, Belo Horizonte, MG 30190-002, Brazil; Programa de Pós Graduação em Medicina Molecular, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Antoniana U
authors.initials: AU
authors.lastname: Krettli
authors.affiliation: Departamento de Síntese de Fármacos, Instituto de Tecnologia em Fármacos, Farmanguinhos-FIOCRUZ, Rua Sizenando Nabuco 100, Manguinhos, Rio de Janeiro, RJ 21041-250, Brazil; Programa de Pós Graduação em Química, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. Electronic address: boechat@far.fiocruz.br.
authors.forename: Nubia
authors.initials: N
authors.lastname: Boechat
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D000090722:Dihydroorotate Dehydrogenase; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D006801:Humans; D051379:Mice; D062105:Molecular Docking Simulation; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000201:enzymology*; D011487:Protein Conformation; D011743:Pyrimidines / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D000962:Antimalarials; D000090722:Dihydroorotate Dehydrogenase; D004791:Enzyme Inhibitors; D011743:Pyrimidines; D044925:Oxidoreductases Acting on CH-CH Group Donors
keywords: Dihydroorotate dehydrogenase (DHODH); Malaria; Molecular docking; P. falciparum; Pyrazolo[1,5-a]pyrimidine