Candimine from Hippeastrum escoipense (Amaryllidaceae): Anti-Trypanosoma cruzi activity and synergistic effect with benznidazole

Abstract

Background: Chagas disease (CD), caused by Trypanosoma cruzi, represents a healththreat to around 20 million people worldwide. Side effects of benznidazole (Bzn)cause 15-20% of patients to discontinue their treatment. Evidence has increased infavour of the use of drug combinations to improve the efficacy and tolerance of thetreatment. Natural products are well known to provide structures that could serve asnew drugs or scaffolds for CD treatment. Spp of the Amaryllidoideae sub family ofAmaryllidaceae family are known by its bioactives alkaloids, which have a reportedantiparasitic activity.Purpose: To evaluate the anti-T. cruzi activity of the isolated alkaloid candimine(Cnd) from Hippeastrum escoipense Slanis & Huaylla; and to assess the combinationeffect between Cnd and Bzn against different life stages of T. cruzi parasites.Methods: The chemical profile of H. escoipense alkaloids extract (AE-H. escoipense),including quantitation of Cnd was performed through GC/MS and UPLC-MS/MStechniques. Subsequently, Cnd was isolated using Shephadex LH20. Then, the AE-H.escoipense and Cnd were tested against T. cruzi, (epimastigotes, trypomastigotes, andamastigotes) by in vitro proliferation and viability assays. The cytotoxicity wasevaluated against Vero and HepG2 mammalian cells. The ultrastructural analysis wasperform by Transmission Electron Microcopy (TEM) and mitochondrial activity wascarried out by MTT assay. Drug combination assay between Cnd and Bzn wasevaluated using the Chou-Talalay method.4Results: The AE-H. escoipense and Cnd showed high and specific anti-T. cruziactivity, comparable to Bzn. Cnd induces ultrastructural changes in T. cruzi, such asvacuolization, membrane blebs and increases the mitochondrial activity. Regarding,the interaction between Cnd and Bzn generates synergism in the combinations of0.25×IC50 in epimastigotes, 2×IC50 in trypomastigotes+amastigotes, and 0.25, 2, and4×IC50 in amastigotes.Conclusion: The synergism between Cnd and Bzn indicates that the combination atthe concentration of 4×IC50 could be useful as an effective new therapy against CD inthe chronic stage. Thus, Cnd isolated from the leaves of the H. escoipense emerges aspotential candidate for the development of a new drug for the treatment of CD.