|Budget Amount *help
¥9,400,000 (Direct Cost : ¥9,400,000)
Fiscal Year 2003 : ¥4,500,000 (Direct Cost : ¥4,500,000)
Fiscal Year 2002 : ¥4,900,000 (Direct Cost : ¥4,900,000)
In this project, our group visited the Democratic Republic of Congo in order to search and collect medicinal plants used for malaria therapy traditionally. With the assistance of Dr. Kubata, a Professor of Kinshasa University and local healers who prescribe medicinal plants to local people we could collect 18 kinds of antimalarial medicinal plants. In the first instance, we evaluated for in vitro growth inhibitory activity on malaria parasites. As a result of our evaluation, 15 kinds of medicinal plants were shown to inhibit proliferation of Plasmodium falciparum potently. Next, We assessed in vivo antimalarial efficacy by use of P. berghei infected mice. In consequence, the three medicinal plants, Euphorbia hirta, Hymenocardia acida, Morinda morindoides, were revealed to exhibit attractive in vivo potency without showing any cytotoxicity. Furthermore, bioassay-guided separation of the MeOH extracts of the three plants resulted in the isolation of flavonol monoglycosides, flavonoid-C-glycosides, and phenyl propanoid conjugated iridoids as responsible active principles. It should be noteworthy that the three active principles are fairly different from known antimalarial drugs in terms of their chemical structures. In addition, all of the three active principles showed antimalarial activity against a drug resistance strain.