LICOCHALCONE-A, A NEW ANTIMALARIAL AGENT, INHIBITS IN-VITRO GROWTH OFTHE HUMAN MALARIA PARASITE PLASMODIUM-FALCIPARUM AND PROTECTS MICE FROM P-YOELII INFECTION

Licochalcone A, isolated from Chinese licorice roots, inhibited the in vitro growth of both chloroquine-susceptible (3D7) and chloroquine-re sistant (Dd2) Plasmodium falciparum strains in a [H-3]hypoxanthine upt ake assay. The growth inhibition of the chloroquine-resistant strain b y licochalcone A was similar to that of the chloroquine-susceptible st rain. To examine the activity of licochalcone A on the different asexu al blood stages of the parasite, licochalcone A was added to highly sy nchronized cultures containing rings, trophozoites, and schizonts. The growth of the parasites at all stages was inhibited by licochalcone A . The in vivo activity of licochalcone A was tested in a mouse model o f infection with P. yoelii. Licochalcone A administered either intrape ritoneally or orally for 3 to 6 days protected the mice from the other wise lethal P. yoelii infection. These results demonstrate that licoch alcone A exhibits potent antimalarial activity and might be developed into a new antimalarial drug.