Haemanthidine-Containing Alkaloid Fraction from <i>Crinum scabrum</i> as a Natural Therapeutics for Chagas Disease

<i>Crinum scabrum</i>, an underexplored species and potential source of the bioactive alkaloid haemanthidine, was investigated. A crude methanolic extract was prepared and subjected to acid-base extraction to obtain an alkaloid-enriched fraction. Four alkaloids were isolated and purified; structural characterization via ¹H and ¹³C NMR spectroscopy, coupled with literature comparison, identified them as haemanthidine/6-<i>epi</i>-haemanthidine (<b>C1</b>/<b>2</b>), crinamine (<b>C3</b>), and hamayne (<b>C4</b>). The extracts and purified compounds were screened against <i>Trypanosoma cruzi</i> (amastigote and trypomastigote forms) and Vero host cells. Fraction III exhibited potent activity against intracellular amastigotes (IC₅₀ = 0.88 ± 0.08 μg mL^-1), comparable to benznidazole (IC₅₀ = 0.75 ± 0.07 μg mL^-1), with exceptional selectivity (SI > 568.2). Critically, no extract and fractions inhibited trypomastigotes (IC₅₀ > 500 μg mL^-1), mirroring benznidazole's stage-specific limitation. For intracellular amastigotes, purified <b>C1/C2</b> (IC₅₀ = 6.05 ± 0.53 μM) and <b>C3</b> (IC₅₀ = 5.79 ± 0.17 μM) showed the highest potency. All compounds exhibited low cytotoxicity (CC₅₀ > 200), yielding exceptional selectivity indices (SI > 80). Additionally, through integrated computational target prediction (PharmMapper) and molecular docking simulations, the study identified and validated the inhibition of <i>T. cruzi</i> GAPDH and Cruzain as key mechanisms of action for the bioactive alkaloids. These findings position <i>C. scabrum</i> alkaloid-enriched fraction as a promising low-toxicity alternative for chronic Chagas disease, warranting <i>in vivo</i> validation and metabolomic profiling to elucidate bioactive cofactors.