In silico and in vitro comparative activity of green tea components against Leishmania infantum

Objectives: Green tea contains a predominant set of polyphenolic compounds with biological activities.
The aim of this study was to investigate the antileishmanial activities of the main components of green
tea, including catechin, (�)-epicatechin, epicatechin gallate (ECG) and (�)-epigallocatechin 3-O-gallate
(EGCG), against Leishmania infantum promastigotes.
Methods: Green tea ligands and the control drug pentamidine were docked using AutoDock 4.3 software
into the active sites of trypanothione synthetase and arginase, which were modelled using homology
modelling programs. The colorimetric MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide] assay was used to measure L. infantum promastigotes at different concentrations of green
tea compounds in a concentration- and time-dependent manner. Results were expressed as 50% and 90%
inhibitory concentrations (IC50 and IC90, respectively).
Results: In silico and in vitro assays showed that all of the green tea compounds have antileishmanial
activity. EGCG and ECG were the most active compounds against L. infantum promastigotes, with IC50
values of 27.7mM and 75mM and IC90 values of 88.4mM and 188.7mM, respectively. Pentamidine
displayed greater growth inhibition than all of the other tested compounds in a concentration- and time-
dependent manner.
Conclusion: In this study, in silico and docking results were in accordance with the in vitro activity of the
compounds. Moreover, EGCG and ECG showed reasonable levels of selectivity for Leishmania.
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