In vitro activity of 2-pyridinecarboxylic acid against trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus = Atividade in vitro do ácido 2-piridinocarboxílico em tripanossoma do subgênero Schizotrypanum isolado do morcego Phyllostomus hastatus

The effect of 2-pyridinecarboxylic acid (picolinic acid) on trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus was determined in this study. Picolinic acid, at 50 êg mL-1, inhibited epimastigote growth by 99% after 12 days incubation. In addition, trypomastigote motility decreased by 50% after 6h and completely after 24h in the presence of 50 êg mL-1 picolinic acid. The 50% cytotoxic concentration on HEp-2 cell line was275 êg mL-1 after 4 days incubation. Altogether, these results indicate higher toxicity against trypanosomes. The inhibitory effect of picolinic acid on epimastigote growth can be partially reversed by nicotinic acid and L-tryptophan, suggesting a competitive inhibition. Furthermore, two anti-Trypanosoma (Schizotrypanum) cruzi drugs were also evaluated with regard to bat trypanosome growth. Benznidazole, at 50 êg mL-1, inhibited epimastigote growth by 90% after 12 days incubation. Nifurtimox, at the same concentration, caused 96% growth inhibition after four days incubation. Corroborating a previous study, bat trypanosomes are a good model for screening new trypanocidal compounds. Moreover, they can be used to study many biological processes common to human pathogenic trypanosomatids. O efeito do acido 2- piridinocarboxilico (acido picolinico) sobre um tripanossoma do subgenero Schizotrypanum isolado do morcego Phyllostomus hastatus foi determinado neste estudo. O acido picolinico, na concentracao de 50 êg mL-1, inibiu 99% do crescimento de epimastigotas apos 12 dias de incubacao. Alem disso, houve um decrescimo de 50 e 100% na mobilidade dos tripomastigotas apos 6 e 24h, respectivamente, em presenca de acido picolinico na concentracao de 50 êg mL-1. A concentracao citotoxica 50% para celulas HEp-2 foi de 275 êg mL-1 apos quatro dias de incubacao. Esses resultados indicam maior toxicidade contra os tripanossomas. O efeito inibitoriodo acido picolinico sobre o crescimento de epimastigotas pode ser parcialmente revertido por acido nicotinico e L-triptofano, sugerindo inibicao competitiva. Adicionalmente, o efeito de dois farmacos com atividade anti-Trypanosoma (Schizotrypanum) cruzi foi avaliado sobre o crescimento do tripanossoma de morcego. Benzonidazol, na concentracao de 50 êg mL-1, inibiu 90% do crescimento de epimastigotas apos 12 dias de incubacao. Nifurtimox, na mesma concentracao, causou 96% de inibicao do crescimento apos quatro dias de incubacao. Corroborando trabalhos anteriores, tripanossomas de morcegos sao bons modelos para selecao inicial de novos compostostripanocidas. Alem disso