O antifúngico clotrimazol (CTZ) tem demonstrado notável atividade contra Plasmodium falciparum. A degradação da hemoglobina por Plasmodium para a obtenção dos aminoácidos necessários à síntese protéica induz estresse oxidativo em eritrócitos devido à liberação de hemos oxidantes. Estes eventos representam alvos bioquímicos para a produção de antimaláricos potenciais. Neste estudo, testamos a capacidade do CTZ para modificar o estado oxidativo em eritrócitos infectados com Plasmodium berghei. Depois da hemólise, as atividades da superóxido dismutase (SOD), catalase (CAT), desidrogenases produtoras de NADPH+H+ e do ciclo de glutationa (GSH) foram investigados. A produção das espécies reativas ao ácido tiobarbitúrico (TBARS) foi avaliada como marcador de dano lipídico. Os resultados mostraram que o CTZ diminuiu a atividade da 6-fosfogliconato desidrogenase (6PGD), em comparação com eritrócitos infectados e não tratados. Consequentemente, o ciclo da GSH foi inibido, tornando os parasitas vulneráveis ao estresse oxidativo resultante da degradação da hemoglobina. Como resposta compensatória, CTZ impediu a perda de atividade da SOD e CAT nas células infectadas. A infecção induz peroxidação lipídica nos eritrócitos, sendo esta diminuída pelo CTZ. Estes resultados sugerem a existência de desequilíbrio redox nas células tratadas com CTZ, interferindo, assim, com o estado oxidativo verificado durante a infecção malárica.

Antimycotic clotrimazole (CTZ) has demonstrated remarkable activity against Plasmodium falciparum in vitro and in vivo. Hemoglobin degradation by Plasmodium parasites makes amino acids available for protein synthesis, inducing oxidative stress in infected cells and producing free heme. These events represent biochemical targets for potential antimalarials. In this study, we have tested the ability of CTZ to modify the oxidative status in Plasmodium berghei-infected erythrocytes. After hemolysis, activities of superoxide dismutase (SOD), catalase (CAT), glutathione cycle and NADPH+H+-producing dehydrogenases were investigated using UV-visible spectrophotometry. Thiobarbituric acid reactive substances (TBARS) were evaluated as a marker of lipid damage. Results showed that CTZ significantly decreased the overall activity of 6-phosphagluconate dehydrogenase (6PGD) compared to infected and non-treated cells; consequently, the glutathione cycle was inhibited, leaving the parasite vulnerable to the oxidative stress originating from hemoglobin degradation. As a compensatory response, CTZ prevented some loss of SOD and CAT activities in infected cells. The infection triggered lipid peroxidation in erythrocytes, which was decreased by CTZ. These results suggest the presence of a redox unbalance in cells treated with CTZ, discussing a possible effect of this compound disturbing the oxidative status in a Plasmodium berghei-infection.

Se describe la síntesis de derivados de las 3-cloro-2N-[1’-alquil- 1’-(4”-clorofenilcarbamoil)metil]amino-1,4-naftoquinonas. Los nuevos compuestos sintetizados fueron caracterizados a través de técnicas espectroscópicas como IR, ¹H RMN, 13C RMN y Espectrometría de Masas. La evaluación biológica de los compuestos obtenidos, fue hecha usando la inhibición de la formación de la beta hematina in vitro y la inhibición del desarrollo de cultivos deP.falciparum. El compuesto 3-cloro-2N-[1’-metil- 1’-(4”clorofenilcarbamoil)metil]amino-1,4-nafto quinona 15 resultó ser el más activo en inhibir el desarrollo de los cultivos de P. falciparum con un Cl50 1.92 μM,n mientras que el compuesto 3-cloro-2N-[1’-(fenilmetil)- 1’-(4” clorofenilcarbamoil)metil]amino-1,4-naftoquinona 17 fue el mejor inhibidor en la formación de la beta-hematina, Cl50 de 6.07 mM. Estos estudios abren una nueva posibilidad para el desarrollo de 3-cloro-2Naminosustituido- 1,4-naftoquinonas como potenciales antimaláricos que puedan ejercer su blanco en la inhibición de la formación de la betahematina y en la inhibición del desarrollo parasitario en cultivos de P. falciparum, los cuales pudiesen ayudar a retrasar el rápido crecimiento de la resistencia. Estos compuestos representan una nueva familia de futuros compuestos antimaláricos.

We described the synthesis of 3-chloro-2N-[1’-alkyl-1’-(4”- chlorophenylcarbamoyl) methyl]amine-1,4-naphthoquinones derivatives. The new compounds were characterized through IR, ¹H NMR, 13C NMR and Mass Spectrometry. The biological evaluation of these derivatives was carry out by inhibition of beta-hematin formation in vitro and the inhibition of cultured P. falciparum parasites. The most active compound resulted the 3-chloro-2N-[1’-methyl-1’-(4”-chlorophenylcarbamoyl) methyl] amine-1,4-naphthoquinone 15, Cl50 1.92 μM, as an inhibitor in cultured P. falciparum parasites, while compound 3-chloro-2N-[1’-(phenylmethyl)- 1’-(4”-chlorophenylcarbamoyl) methyl]amine-1,4-naphthoquinone 17 was the best as inhibitor of beta-hematin formation with an Cl50 of 6.07 mM. These studies open up the novel possibility of development of 3-chloro-2Naminesubstituted- 1,4-naftoquinonas derivatives as potentials antimalarials that target beta-hematin formation and the inhibition of the development of cultured P. falciparum parasites, which should help delay the rapid onset of resistance to drugs acting at only a single site. These compounds represent a new family of promising antimalarials.