Vangueria infausta root bark:: in vivo and in vitro antiplasmodial activity

Vangueria infausta burch subsp. infausta (Rubiaceae) produces fruits eaten by humans and animals. The leaf, fruit, stem bark and root bark are used as a remedy for many ailments and the roots are used to treat malaria. In this study, concentrations of fractions of the V infausta root bark extract that produce 50% inhibition (IC50) are determined using the ability of the extract to inhibit the uptake of [G(3)H]-hypoxanthine by P. falciparum cultured in vitro. The root bark extract showed antimalarial activity against Plasmodium berghei in mice. It gave a parasite suppression of 73.5% in early infection and a repository effect of 88.7%. One fraction obtained from a chloroform extract gave an IC50 value of 3.8 +/- 1.5 mu g/mL and 4.5 +/- 2.3 mu g/mL against D-6 and W-2 strains of P. falciparum, respectively, and another from the butanol extract gave an IC50 value of 3.9 +/- 0.3 mu g/mL against the D6 strain. Chloroquine had an IC50 value of 0.016 mu g/mL and 0.029 mu g/mL against D-6 andW(2) strains, respectively. The plant showed the presence of flavonoids, coumarins, tannins, terpenoids, anthraquinones and saponins.