Comparative Phytochemical Analysis of Carica papaya Leaf and Seed Extracts and Their Activity Against Plasmodium falciparum In Vitro

Carica papaya is one of the most commonly used medicinal plants in Nigeria, with both leaf and seed preparations employed across all geopolitical zones for the management of malaria, particularly in rural households with limited access to artemisinin-based combination therapies. This study comparatively analyses the phytochemical composition of leaf and seed extracts of Carica papaya and evaluates their in vitro antimalarial activity against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Plant materials were sourced from farms in Ondo State, South West Nigeria. Aqueous and methanol extracts were prepared by cold maceration. Standard phytochemical screening, thin layer chromatography, and gas chromatography-mass spectrometry (GC-MS) analysis were performed. In vitro antimalarial activity was assessed using the lactate dehydrogenase (LDH) assay. Phytochemical screening revealed higher concentrations of alkaloids and carpaine derivatives in the leaf extract, while the seed extract was richer in benzyl isothiocyanate and glucosinolates. Both extracts demonstrated concentration-dependent inhibition of P. falciparum growth, with the leaf methanol extract showing the lowest IC50 values. Seed extracts showed moderate activity against the chloroquine-resistant strain. These findings provide pharmacological support for the continued ethnomedicinal use of Carica papaya in malaria management. Keywords: Carica papaya, antimalarial, Plasmodium falciparum, phytochemical, in vitro