Abstract
Plasmodium falciparum (P. falciparum), the most lethal malaria agent, has acquired resistance to most widely used antimalarial drugs. Consequently, malaria continues to be a global health burden. The World Health Organisation has reported that there were 249 million malaria-related deaths in 2022 alone. There is a need to find alternative antimalarial drugs to control malaria, making it imperative to explore plant-derived compounds in the search for novel antimalarial compounds. Iso-mukaadial acetate (IMA) is a compound derived from a medicinal plant, Warbugia salutaris, and has been shown to have antiplasmodial activity however its mechanism of action remains unclear. This study aimed to decipher the IMA antiplasmodial mechanism by studying the changes in P. falciparum gene expression in response to IMA treatment. To achieve this, an antiplasmodial activity assay was conducted to obtain IMA-treated P. falciparum cultures for downstream transcriptomics analysis. In vitro, the antiplasmodial activity of lMA against P. falciparum (NF54) was investigated using the parasite lactate dehydrogenase (pLDH) assay and the activity compared with the standard antimalarial drug, chloroquine, as a positive control. RNA was extracted from IMA-treated and untreated parasitized erythrocytes. RNA was sequenced using MGISeq-2000 sequencer, and the sequencing data obtained was analyzed using Gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) to gain insights into the biological processes, molecular functions and pathways that were significantly impacted by IMA treatment. IMA showed antiplasmodial activity against the P. falciparum NF54 strain, with an IC50 value of 2.49530 μM. Differentially expressed genes were identified between the IMA-treated and untreated P. falciparum. Biological processes and molecular functions that were enriched with downregulated genes include cellular response to heat and (ATP)-dependent protein folding chaperone, KEGG analysis showed that IMA downregulated key enzymes involved in metabolic pathways such as glycolysis, DNA replication and pentose phosphate pathway. These findings shed light on the antiplasmodial mechanism of IMA.