Anti-Leishmanial and Immunomodulatory Effects of Epigallocat-echin 3-O-Gallate on Leishmania tropica: Apoptosis and Gene Expression Profiling

Background: Pentavalent antimonials such as meglumine antimoniate (MA, Glucantime), are the first-line treatment against leishmaniasis, but at present, they have basically lost their efficacy. This study was aimed to explore epigallocatechin 3-O-gallate (EGCG), alone or in combination with MA against Leishmania tropica stages. Methods: All experiments were carried out in triplicate using colorimetric assay, macrophage model, flow cytometry and quantitative real-time PCR. This experimental study was carried out in 2017 in Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran. Results: Promastigotes and amastigotes were more susceptible to EGCG than MA alone, but the effect was more profound when used in combination. EGCG exhibited high antioxidant level with a remarkable potential to induce apoptosis. Furthermore, the results showed that the level of gene expression pertaining to Th-1 was significantly up-regulated (P<0.001). Conclusion: EGCG demonstrated a potent anti-leishmanial effect alone and more enhanced lethal activity in combination. The principal mode of action entails the stimulation of a synergistic response and up-regulation of the immunomodulatory role towards Th-1 response against L. tropica.