Haemanthidine-Containing Alkaloid Fraction from Crinum scabrum as a Natural Therapeutics for Chagas Disease

Crinum scabrum, 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-epi-haemanthidine (C1/2), crinamine (C3), and hamayne (C4). The extracts and purified compounds were screened against Trypanosoma cruzi (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 C1/C2 (IC₅₀ = 6.05 ± 0.53 μM) and C3 (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 T. cruzi GAPDH and Cruzain as key mechanisms of action for the bioactive alkaloids. These findings position C. scabrum alkaloid-enriched fraction as a promising low-toxicity alternative for chronic Chagas disease, warranting in vivo validation and metabolomic profiling to elucidate bioactive cofactors.