Exploring the Antimalarial Potential of <i>Entandrophragma Utile</i> and <i>Melochia Umbellata</i> Extracts

Abstract

Resistance remains the fundamental problem with antiplasmodial treatments. The study investigated the antiplasmodial, cytotoxic, and antioxidant properties of two Cameroonian medicinal plants, Entandrophragma utile and Melochia umbellata. Antimalarial activity against Plasmodium falciparum strains 3D7 and Dd2 was assessed using the SYBR Green I assay. Cytotoxicity was assessed against Raw and Vero cells using the resazurin assay, and against red blood cells using a hemoglobin release quantification assay. Antioxidant potential was determined using DPPH (2, 2-diphenyl-1-picrylhydrazine), ABTS (2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), and FRAP (ferric-reducing antioxidant power) assays. The most bioactive extract was further analyzed using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) to determine its phytochemical composition. Extracts from E. utile exhibited moderate anti-malarial activity against Plasmodium falciparum (IC₅₀ =32.81-100 μg/mL), while M. umbellata leaf extract (MULAE) showed strong activity (IC₅₀ =11.62 and 11.91 μg/mL). All extracts demonstrated antioxidant activity (9.22 to 135.8 μg/mL), were selective for Raw and Vero cells, and were not toxic to red blood cells. UHPLC-MS analysis annotated potential pyrimidones, phenolic compounds, and terpenoids in MULAE. MULAE exhibited better antiplasmodial activity, suggesting the presence of unique bioactive compounds. Further research, including in vivo investigations, is needed to develop safe and effective antiplasmodial therapies.