Chemotherapeutic Interaction of Vernonia amygdalina (Delile) Leaf Extract with Artesunate and Amodiaquine in Murine Malaria Model

Aim of the Study: Conventional antimalarial drugs are used concurrently with herbal remedies in malarial endemic developing countries. Vernonia amygdalina is one of such popular herbs used in the treatment of malaria. This study aimed at investigating the antimalarial chemotherapeutic interaction of Vernonia amygdalina (VA) when combined with Amodiaquine (AQ) and/or Artesunate (AS) in a murine Plasmodium berghei malaria model.

Methodology: Various doses of aqueous VA leaf extract (100-500 mg/kg/day), AQ (2-10 mg/kg/day) and AS (0.8-4 mg/kg/day) were administered orally to P berghei.-infected Swiss albino mice to determine their sub-therapeutic doses. These doses were subsequently used to investigate the chemotherapeutic interactions of VA with AQ and/or AS in both early and established malaria infection test models. The survival of animals with established infections that received different drug/herb treatments were determined using their mean survival time (days) and Kaplan-Meier survival curves (percentage). Using GraphPad Instat (version 3.10) and PrismR (version 5.01) the data obtained were subjected to One-way ANOVA, followed by Student-Newman-Keuls test. P < .05 was considered statistically significant.

Results: The sub-therapeutic doses of VA, AQ and AS were found to be 100 mg/kg, 2 mg/kg and 2.4 mg/kg, respectively. The chemosuppressive effect of AQ or AS was significantly increased (p< 0.05) when administered in combination with the VA extract. Similarly, combination of VA extract with AQ or AS resulted in significant (P < .05) parasite clearance when compared to the effects of the herb or the conventional drugs administered separately. The mean survival period of animals with established infection was also significantly enhanced by the VA alone or with AQ (or AS) compared to placebo.