Computational aided search of polyphenols with trypanocidal activity.

REIGADA C; VALERA VERA EA; MIRANDA MR; SAYÉ M; PEREIRA CA; REIGADA C; VALERA VERA EA; MIRANDA MR; SAYÉ M; PEREIRA CA

Ciudad Autónoma de Buenos Aires

Congreso; Drug Discovery for Neglected Diseases International Congress 2018; 2018

Arginine kinase (AK) is a highly conserved protein of invertebrates that is also found in trypanosomatids. It catalyzes thereversible transference of phosphate between ATP and arginine to help maintaining the energetic balance in conditionswhen more energy is needed; and in Trypanosoma cruzi appears to be a key enzyme for stress response. Different plantextracts have shown inhibition of the enzyme activity in a wide range of organisms including trypanosomatids, andmore precisely some polyphenols have been successfully identified as inhibitors.In this work we used computational techniques to find possible inhibitors of the T. cruzi AK (TcAK) and testedtheir inhibitory capabilities on the enzyme activity and different life cycle stages of the parasite. With this end, ahomology model of the protein was generated with the iTASSER server to use in molecular docking with a database of 326polyphenols found in plants, using the software AutoDock 4.5. The compounds predicted to have a stronginteraction with the AK active site that also are easily accessible in the market were further tested against recombinantTcAK in inhibition assays in the sense ATP + arginine → ADP + P-Arginine, using coupled reactions to measure NADHconsumption. Also, in vitro activity was assayed over epimastigotes, trypomastigotes and Vero cell cultures infectedwith T. cruzi, counting cells after exposition with different concentration of the compounds. Finally, cytotoxicity overVero cells was assayed and measured by fixation of the remaining cells and tincture with crystal violet.Capsaicin and delphinidin were the molecules that showed the strongest trypanocidal effect in the nanomolar rangeon either stage of the parasite life-cycle with high selectivity indexes against Vero cell cultures, but only delphinidinshowed to be a strong AK inhibitor, with an IC50 of 7uM. Further metabolic studies and computational analysis will beperformed to test if AK is indeed the molecular target of polyphenols in their trypanocidal activity; either way, thehigh anti-parasitic activity and selectivity of these molecules show the strong potential of these polyphenols as leadcompounds in the search for new drugs against Chagas disease.