RESUMO
Caffeic acid and related natural compounds were previously described as Leishmania amazonensis arginase (L-ARG) inhibitors, and against the whole parasite in vitro. In this study, we tested cinnamides that were previously synthesized to target human arginase. The compound caffeic acid phenethyl amide (CAPA), a weak inhibitor of human arginase (IC50 = 60.3 ± 7.8 µM) was found to have 9-fold more potency against L-ARG (IC50 = 6.9 ± 0.7 µM). The other compounds that did not inhibit human arginase were characterized as L-ARG, showing an IC50 between 1.3-17.8 µM, and where the most active was compound 15 (IC50 = 1.3 ± 0.1 µM). All compounds were also tested against L. amazonensis promastigotes, and only the compound CAPA showed an inhibitory activity (IC50 = 80 µM). In addition, in an attempt to gain an insight into the mechanism of competitive L-ARG inhibitors, and their selectivity over mammalian enzymes, we performed an extensive computational investigation, to provide the basis for the selective inhibition of L-ARG for this series of compounds. In conclusion, our results indicated that the compounds based on cinnamoyl or 3,4-hydroxy cinnamoyl moiety could be a promising starting point for the design of potential antileishmanial drugs based on selective L-ARG inhibitors.
Assuntos
Antiprotozoários/farmacologia , Arginase/antagonistas & inibidores , Cinamatos/farmacologia , Inibidores Enzimáticos/farmacologia , Leishmania/enzimologia , Proteínas de Protozoários/antagonistas & inibidores , Animais , Sítios de Ligação , Ácidos Cafeicos/química , Bovinos , Cinamatos/química , Desenho de Fármacos , Humanos , Concentração Inibidora 50 , Cinética , Ligantes , Simulação de Dinâmica Molecular , Conformação Proteica , Proteínas Recombinantes/químicaRESUMO
This study describes the activity of five natural hydroxycinnamic acids and derived compound: caffeic (1), rosmarinic (2), chlorogenic (3), and cryptochlorogenic (4), acids and isoverbascoside (5). All compounds inhibited Leishmania amazonensis arginase with IC50 -in range of 1.5-11 µM. Compounds 2 and 5 also showed activity against promastigotes of L. amazonensis with IC50 = 61 (28-133) µM and IC50 = 14 (9-24) µM, respectively. Further computational studies applying molecular docking simulations were performed on the competitive inhibitors to gain insight into the molecular basis for arginase inhibition and could be exploited to the development of new antileishmanials drug targeting parasite arginase.
Assuntos
Antiprotozoários/química , Arginase/metabolismo , Cinamatos/química , Leishmania/enzimologia , Proteínas de Protozoários/metabolismo , Antiprotozoários/metabolismo , Antiprotozoários/farmacologia , Arginase/antagonistas & inibidores , Sítios de Ligação , Cinamatos/metabolismo , Concentração Inibidora 50 , Cinética , Leishmania/efeitos dos fármacos , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Proteínas de Protozoários/antagonistas & inibidoresRESUMO
Verbascoside (1) is a phenylethanoid glycoside that has antileishmanial activity against Leishmania infantum and Leishmania donovani. In this study, we verified the activity of 1 on Leishmania amazonensis and arginase inhibition. Compound 1 showed an EC50 of 19 µM against L. amazonensis promastigotes and is a competitive arginase inhibitor (Ki = 0.7 µM). Docking studies were performed to assess the interaction of 1 with arginase at the molecular level. Arginase is an enzyme of the polyamine biosynthesis pathway that is important to parasite infectivity, and the results of our study suggest that 1 could be useful to develop new approaches for treating leishmaniasis.