Malaria treatment and control have become increasingly difficult because of the spread
of drug-resistant strains of Plasmodium falciparum and Plasmodium vivax. Thus, there is a continuous need to develop new combination therapies such as artemisinin-based
combination therapies (ACTs) to contrast the emergence of resistant Plasmodium strains. Despite ACT has been recommended by the World Health Organization since
2001, its overall deployment in poor endemic areas is very slow, principally due to
its high cost. In the malaria endemic areas, plant remedies are still widely used
mostly without assurance of their efficacy and/or safety. A variety of widespread
herbal drugs or natural products were already reported for their possible plasmodicidal
activities, but the studies concerning their activity in combination with artemisinins
are very scarce. The antimalarial activity of papaya is mostly anecdotal, and the
present study is aimed at investigating the antiplasmodial activity of a decoction
obtained by traditional recipe from the mature leaves of Carica papaya. The decoction was analyzed by HPLC-DAD-MS (high performance liquid chromatography
coupled with diodoarray detector and mass spectrometry) showing the presence of caffeoyl
derivatives and di- and triglycosides of flavonols. The extract was found to be active
against P. falciparum 3D7 strains with a synergism in the presence of artemisinin. In vivo activity against the murine malaria model of Plasmodium berghei was disclosed both for the dried extract alone (250, 500, and 750 mg/kg/d) and for
its combination with artesunate (250 mg/kg/d papaya plus 10 mg/kg/d artesunate). This
combination displayed the greatest antimalarial activity in terms of reduction of
parasitemia and prevention of recrudescence in animals recovered from the infection.
Key words
Carica papaya
- Caricaceae - traditional mature leaf decoction - artemisinin and artesunate -
in vitro synergistic effect -
in vivo activity and recrudescence control
