In vitro experiments evaluated ethanolic soursop-leaf extract against zoonotic Plasmodium knowlesi. The extract inhibited blood-stage development with a reported IC50 of 9.65 micrograms per milliliter and reduced binding of infected red blood cells to endothelial cells. The effect was parasitostatic rather than parasite-killing and is not evidence of efficacy in patients.
Key findings
- The extract inhibited schizogony, particularly at the trophozoite stage, with activity concentrated in the fraction below 30 kDa. Morphologically intact parasites resumed growth after washout, supporting a parasitostatic effect. Endothelial-cell priming also significantly reduced infected-red-cell binding as reported.
Why this matters globally
The work provides a starting point for isolating active constituents and studying mechanisms potentially relevant to knowlesi-malaria complications. Product development would require chemical identification, batch standardization, toxicology, pharmacokinetics, drug-interaction studies, and animal and human efficacy evidence.
Thai researcher contribution
Researchers affiliated with Mahidol University and Walailak University joined an international collaboration on zoonotic malaria, linking Thai expertise in tropical medicine, parasitology, and vascular mechanisms.
Limitations to consider
This is a reference-strain and cell-culture study. Safe dosing, absorption, metabolism, neurotoxicity or hepatotoxicity, plant-composition variability, and effects in animals or patients are unknown. An in vitro IC50 is not an oral dose, and soursop leaves should not replace standard antimalarial treatment.