Antiplasmodial Activity of the Ethanolic Extract and Flavonoid Fraction of the Stem of Phyllanthus amarus in Experimental Mice

Malaria infestation in Nigeria is still worrisome, hence, the need for new antimalarial agents. This study, therefore, investigates the antiplasmodial activity of the ethanolic extract and flavonoid fraction of the stem of P. amarus in the blood, brain, liver and pancreas of Plasmodium berghei (chloroquine sensitive NK65 strain) infested mice. Forty (40) adult male BALB/C mice, weighing between 20-30g were randomly divided into eight (8) groups (n=5 mice per group) and treated with varying doses (150, 300 and 450 mg/kg/d) of either the ethanolic extract or the flavonoid fraction of the stem of P. amarus for seven (7) days. The animals were euthanized on the 8th day after an overnight fast under chloroform anaesthesia, and smears of the blood and tissues were processed for parasite count using Giemsa stain. Results show significant (p< 0.05) in vivo antiplasmodial activity by the ethanolic extract in a dose-dependent manner, which compared well with the standard chloroquine treatment. However, treatment with the flavonoid fraction yielded minimal growth suppression. The observed active antiplasmodial activity of the ethanolic extract of the stem of P. amarus is therefore, not traceable to the flavonoid phytochemical. The active antiplasmodial phytochemical(s) in the ethanolic extract of the stem of P. amarus need to be identified by further study.