Antiplasmodial activity of leaf extract and fractions of Hiern (Rubiaceae)

Background: Resistance to malaria infection has been of great public health concern all over the world especially in developing countries thus there is need for development of new antimalarial drugs. Natural products including medicinal plants are veritable sources for drug discovery hence their investigation for possible antimalarial effects. Rutidea smithii is a woody climbing plant used traditionally in treatment of headache, cold and fever.

Objective: To investigate the in vivo antimalarial activity of ethanol leaf extract and fractions of Rutidea smithii in chloroquine sensitive Plasmodium berghei infected mice.

Methods: Swiss albino mice were intraperitoneally infected with chloroquine sensitive P. berghei (ANKA strain). The mice were treated orally using suppressive and curative models with graded doses of extract of R. smithii (100, 200 and 400 mg/kg), fractions (50, 100 and 200 mg/kg) and standard antimalarial drug; chloroquine (10 mg/kg). Preliminary phytochemical screening and acute toxicity study were also carried out.

Results: In the suppressive and curative tests, the extract demonstrated significant dose reduction in parasite level (p < 0.05) in infected mice and the survival time was also prolonged. The antimalarial activity of the fractions increased in the order hexane < butanol < aqueous < ethylacetate. The extract was devoid of toxicity up to the highest dose tested (2000 mg/kg).

Conclusion: Rutidea smithii has potent in vivo antiplasmodial activity against P. berghei which resides mainly in ethylacetate fraction thus is a veritable source of new antimalarial agents.