Evaluation of in vitro antimalarial activity of <i>Citrus aurantifolia</i> (CHRISTM.) and <i>Ziziphus mauritiana</i> (LAM) using heme polymerization inhibition assay

Abstract

Citrus aurantifolia and Ziziphus mauritiana (Lam) are plants that have numerous medicinal properties and are used extensively in traditional medicine for the treatment of several diseases. Malaria parasites metabolize haemoglobin and detoxify the resulting haem by polymerizing it to form haemozoin (malaria pigment). This study aimed at evaluating the antiplasmodial activity through in vitro cell-free heme polymerization inhibition assay (HPIA) of C. aurantifolia and Z. mauritiana. The analysis was conducted using a 96-well microtiter plate reader at an absorption of 400 nm, at different concentrations (0-2 mg/ml). The IC₅₀ was determined by non-linear regression analysis using GraphPad Prism. The result indicated that both the root extracts of C. aurantifolia and Z. mauritiana showed significant difference (p˂0.0001) with IC₅₀ of 0.81 mg/ml and 0.77 mg/ml respectively compared to positive control. Phytochemical screening of the ethanol root extracts showed the presence of saponins, alkaloids, terpenoids, glycosides, steroids, and anthraquinone, while tannins and reducing sugars were not detected in both samples used, flavonoid was detected in C. aurantifolia. Both the extracts exhibited potential for inhibiting heme polymerization in vitro.