Malaria remains a major global health burden, driven largely by Plasmodium falciparum and worsened by resistance to artemisinin-based combinations. This dissertation investigates PRC1584, a β-carboline antimalarial lead with rapid, potent activity against asexual blood stages, most pronounced from late ring to early trophozoite. Brief exposures trigger morphological quiescent/pyknotic forms reminiscent of dihydroartemisinin-associated dormancy, however, ring-stage dormancy can arise independently of any specific agent. Cross-resistance sensitivity profiling showed that parasites with the Kelch13-C580Y mutation are more sensitive in certain conditions than wild type strains, suggesting that endocytic pathways linked to K13 may play a role in how this mechanism works. Electron microscopy demonstrated disrupted cytostomes with abnormal invaginations and fewer endocytic or digestive vesicles that contained hemoglobin. Biochemical fractionation and heme quantification revealed a reduction in parasite heme levels as well as less hemozoin formation. These results indicate that PRC1584 disrupts cytostome-mediated hemoglobin uptake and subsequent delivery to the digestive vacuole. Together, these findings position PRC1584 as a fast-actingdisruptor of cytostome-mediated hemoglobin uptake, an essential pathway for parasite growth. To enable target discovery using chemoproteomics, two analogs were developed: an intermediate scaffold (PRC1859) and a diazirine–azide photoaffinity probe (PRC1860). Under continuous exposure, both preserved parent-like potency and reproduced PRC1584-like morphology, supporting on-pathway action suitable for chemoproteomic capture. At the same time, repeated attempts to select stable PRC1584-resistant lines were unsuccessful, indicating that resistance is unlikely to develop easily—PRC1584 appears to have an "irresistible" profile under the conditions tested. Although definitive molecular targets were not identified, this work delivers validated probes and workflows that establish a practical foundation for future target identification. Altogether, the dissertation characterizes PRC1584 as an antimalarial with nanomolar potency against asexual blood stages and an unusual efficacy signature that includes collateral sensitivity in artemisinin-tolerant parasites, durable effects after brief exposure, and failure to select resistance in vitro. These properties argue for the development of PRC1584 analogs primarily as a combination partner—a targeted starvation agent orthogonal to heme detoxification and peroxide activation—that can be scheduled to complement rapid-clearing schizonticides, suppress recrudescence, and maintain activity in K13-variant settings while minimizing cross-resistance.
