title: In Vivo antimalarial activity of aqueous extracts from Kenyan medicinal plants and their chloroquine (CQ) potentiation effects against a blood-induced CQ-resistant rodent parasite in mice.
abstract: Hot water extracts from eight medicinal plants representing five families, used for malaria treatment in Kenya were screened for their in vivo antimalarial activity in mice against a chloroquine (CQ) resistant Plasmodium berghei NK65, either alone or in combination with CQ. Extracts of three plants, Toddalia asiatica (root bark), Rhamnus prinoides (leaves and root bark) and Vernonia lasiopus (root bark) showed high chemosuppression in the range 51%-75%. Maytenus acuminata, M. heterophylla, M. senegalensis and Rhamnus staddo had moderate activities of 33%-49% parasitaemia suppression in the root bark and/or leaf extracts, while Withania somnifera (root bark) had a non-significant suppression (21%). In combination with CQ, extracts of V. lasiopus (all parts), leaf extracts of M. senegalensis, R. prinoides and T. asiatica as well as root barks of M. heterophylla, R. staddo and T. asiatica had improved parasitaemia suppression in the range 38%-66%, indicating synergistic interactions. Remarkable parasitaemia suppression by the extracts, either alone or in combination with CQ resulted into longer survival of mice relative to the controls, in some cases by more than 2 weeks. Plants, which showed significant antimalarial activity including V. lasiopus, T. asiatica and R. prinoides, should further be evaluated in the search for novel agents against drug-resistant malaria.
authors.affiliation: Department of Parasitology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan. fmuregi@hama-med.ac.jp
authors.forename: Francis W
authors.initials: FW
authors.lastname: Muregi
authors.forename: Akira
authors.initials: A
authors.lastname: Ishih
authors.forename: Tohru
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hideto
authors.initials: H
authors.lastname: Kino
authors.forename: Teruaki
authors.initials: T
authors.lastname: Amano
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Mkoji
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyase
authors.forename: Mamoru
authors.initials: M
authors.lastname: Terada
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology* / Q000627:therapeutic use; D002738:Chloroquine / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D007630:Kenya; D008288:Malaria / Q000188:drug therapy*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D010946:Plants, Medicinal; D010962:Plasmodium berghei / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D010936:Plant Extracts; D002738:Chloroquine