Chemo Suppressive and Curative Potential of Hypoestes forskalei Against Plasmodium berghei: Evidence for in vivo Antimalarial Activity

Background: The emergence of drug resistance together with the global burden of malaria triggers the necessity for the searching of new antimalarial agents. This study, therefore, was initiated to investigate the in vivo antimalarial activity of Hypoestes forskalei in mice based on the strong supported evidence from the ethnobotanical claims and the in vitro anti-plasmodial activity of the plant.

Methods: The 4-day suppressive (crude extract and fractions) and the Rane's (n-butanol fraction) tests were used to evaluate the antimalarial activity of the plant. A cold maceration technique with 80% methanol was used for the crude extraction of the plant. The crude extract was then fractionated using solvents of different polarity (chloroform, n-butanol, and water).

Results: All the test doses of the crude extract as well as the fractions reduced parasitemia and prolonged mean survival time significantly (P<0.001) as compared to their negative control groups. Maximum parasitemia suppression effect (56%) was observed at the highest dose (600 mg/kg) of the crude extract during the 4-day suppressive test. Likewise, the n-butanol, chloroform, and aqueous fractions showed a percentage suppression of about 50, 38, and 19, respectively, at the dose of 600 mg/kg. Therefore, the n-butanol fraction showed the highest parasitemia suppression followed by the chloroform fraction and then the aqueous fraction. Moreover, the n-butanol fraction showed a significant curative effect (P<0.001) in Rane's test with a percentage suppression of about 49 at a dose of 600 mg/kg.

Conclusion: The study has revealed that the plant has a promising antimalarial activity, the activity being more in the crude extract than the fractions. The highest antimalarial activity of the n-butanol fraction suggests that non-polar and medium polar principles could be responsible for the observed activity.

Keywords: Hypoestes forskalei; Plasmodium berghei; antimalarial activity; parasitemia.