Flavonoid-rich Albizia niopoides leaf extract shows anti-Trypanosoma cruzi activity against benznidazole-resistant parasites

Chagas disease affects approximately 6–7 million people worldwide, with current treatments limited by toxicity and parasite resistance. This study evaluated ethanolic extracts from stems and leaves of three Brazilian Cerrado species ( Curatella americana , Nectandra nitidula , and Albizia niopoides ) against the benznidazole-resistant Trypanosoma cruzi Y strain (DTU II) in vitro. Cytotoxicity assessment in Vero cells revealed high toxicity for most extracts, with only A. niopoides leaves showing a favorable therapeutic window (CC 50 > 1600 µg/mL). Against epimastigotes, A. niopoides leaf extract exhibited the highest antiparasitic effect (IC 50 = 150.72 µg/mL) among plant extracts. This extract was selected for intracellular amastigote assays in H9c2 cardiomyocytes, achieving 85.9% inhibition at 400 µg/mL with an IC 50 of 150.72 µg/mL. The selectivity index was > 10.61 in Vero cells and 1.6 in H9c2 cells, remaining below the threshold of ≥ 50 recommended for drug development. UHPLC-MS analysis identified four flavonoids: rutin (50.2% relative abundance), isoquercitrin (7.5%), luteolin-7- O -rutinoside (1.9%), and 7- O -methyl- quercetin (25.3%) as potential chemical markers. These identifications were classified as Metabolomics Standards Initiative (MSI) Level 2 (rutin, isoquercitrin, and luteolin-7- O -rutinoside, confirmed against authentic standards) and Level 3 (7- O -methyl-quercetin, tentative). These findings identify flavonoid glycosides as potential chemical markers in A. niopoides leaves with activity against benznidazole-resistant parasites, providing defined targets for future bioassay-guided fractionation. However, the modest selectivity and lack of isolated compound testing preclude conclusions about therapeutic potential at this stage.