Kaempferol-3-O-alpha-(3,4-di-E-p-coumaroyl)-rhamnopyranoside from Nectandra oppositifolia releases Ca2+from intracellular pools of Trypanosoma cruzi affecting the bioenergetics system

Author(s)

Conserva, Geanne A. ^[1] ; Costa-Silva, Thais A. ^[1] ; Quiros-Guerrero, Luis M. ^{[2, 3]} ; Marcourt, Laurence ^{[2, 3]} ; Wolfender, Jean-Luc ^{[2, 3]} ; Queiroz, Emerson F. ^{[2, 3]} ; Tempone, Andre G. ^[4] ; Lago, Joao Henrique G. ^[1]

Affiliation

^[1] Fed Univ ABC, Ctr Nat Sci & Humanities, BR-09210180 Santo Andre, SP - Brazil

^[2] Univ Geneva, Sch Pharmaceut Sci, Geneva - Switzerland

^[3] Univ Geneva, Inst Pharmaceut Sci Western Switzerland ISPSW, Geneva - Switzerland

^[4] Adolfo Lutz Inst, Ctr Parasitol & Mycol, BR-01246000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Chemico-Biological Interactions; v. 349, NOV 1 2021.
• Web of Science Citations: 0

Abstract

Phytochemical analysis of EtOH extract from leaves of Nectandra oppositifolia afforded three flavonoids: kaempferol (1), kaempferol-3-O-alpha-rhamnopyranoside (2) and kaempferol-3-O-alpha-(3,4-di-E-p-coumaroyl)-rhamnopyranoside (3), which were characterized by NMR and ESI-HRMS. When tested against the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, flavonoids 1 and 3 were effective to kill the trypomastigotes with IC50 values of 32.0 and 6.7 mu M, respectively, while flavonoid 2 was inactive. Isolated flavonoids 1-3 were also tested in mammalian fibroblasts and showed CC50 values of 24.8, 48.7 and 153.1 mu M, respectively. Chemically, these results suggested that the free aglycone plays an important role in the bioactivity while the presence of p-coumaroyl unities linked in the rhamnoside unity is important to enhance the antitrypanosomal activity and reduce the mammalian cytotoxicity. The mechanism of cellular death was investigated for the most potent flavonoid 3 in the trypomastigotes using fluorescent and luminescent-based assays. It indicated that this compound induced neither permeabilization of the plasma membrane nor depolarization of the membrane electric potential. However, early time incubation (20 min) with flavonoid 3 resulted in a constant elevation of the Ca2+ levels inside the parasite. This effect was followed by a mitochondrial imbalance, leading to a hyperpolarization and depolarization of the mitochondrial membrane potential, with reduction of the ATP levels. During this time, the levels of reactive oxygen species levels (ROS) were unaltered. The leakage of Ca2+ from the intracellular pools can affect the bioenergetics system of T. cruzi, leading to the parasite death. Therefore, flavonoid 3 can be a useful tool for future studies against T. cruzi parasites. (AU)

• FAPESP's process: 16/20633-6 - Bioactive metabolites from Nectandra oppositifolia Nees & Mart. (Lauraceae): molecular characterization, in vitro and in vivo antiparasitic potential evaluation and determination of mechanism of action
• Grantee: Geanne Alexsandra Alves Conserva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 21/04464-8 - Microbial and plant prototypes as drug candidates for protozoan neglected diseases and multidrug-resistant bacteria
• Grantee: André Gustavo Tempone Cardoso
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/02789-7 - Search for bioactive metabolites with antiparasitic action in plant species from Atlantic Forest and Cerrado regions - a chemical, phenotypical, and metabolomic approach
• Grantee: João Henrique Ghilardi Lago
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 18/18975-1 - Dereplication profile of Nectandra oppositifolia Nees & Mart. (Lauraceae): identification and molecular characterization of antiparasitic metabolites
• Grantee: Geanne Alexsandra Alves Conserva
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate