ABSTRACT
Two new antimalarial compounds, named prenylpyridones A (1) and B (2), were discovered from the actinomycete cultured material of Streptomyces sp. RBL-0292 isolated from the soil on Hamahiga Island in Okinawa prefecture. The structures of 1 and 2 were elucidated as new iromycin analogs having α-pyridone ring by MS and NMR analyses. Compounds 1 and 2 showed moderate in vitro antimalarial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with IC50 values ranging from 80.7 to 106.7 µM.
Subject(s)
Antimalarials , Plasmodium falciparum , Streptomyces , Streptomyces/metabolism , Antimalarials/pharmacology , Antimalarials/chemistry , Antimalarials/isolation & purification , Plasmodium falciparum/drug effects , Magnetic Resonance Spectroscopy , Soil Microbiology , Inhibitory Concentration 50 , Pyridones/pharmacology , Pyridones/chemistry , Chloroquine/pharmacology , Mass Spectrometry , Molecular Structure , Drug ResistanceABSTRACT
Three new antiplasmodial compounds, named akedanones A (1), B (2), and C (3), were discovered from the cultured material of Streptomyces sp. K20-0187 isolated from a soil sample collected at Takeda, Kofu, Yamanashi prefecture in Japan. The structures of compounds 1-3 were elucidated as new 2,3-dihydronaphthoquinones having prenyl and reverse prenyl groups by mass spectrometry and nuclear magnetic resonance analyses. Compound 1 and the known furanonaphthoquinone I (4) showed potent in vitro antiplasmodial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with half-maximal inhibitory concentration values ranging from 0.06 to 0.3 µM. Compounds 1 and 4 also displayed potent in vivo antiplasmodial activity against drug-sensitive rodent malaria Plasmodium berghei N strain, with inhibition rates of 47.6 and 43.1%, respectively, on intraperitoneal administration at a dose of 5 mg kg-1 day-1 for 4 days.
Subject(s)
Antimalarials , Naphthoquinones , Plasmodium berghei , Plasmodium falciparum , Streptomyces , Antimalarials/pharmacology , Antimalarials/chemistry , Plasmodium falciparum/drug effects , Streptomyces/chemistry , Naphthoquinones/pharmacology , Naphthoquinones/chemistry , Molecular Structure , Plasmodium berghei/drug effects , Animals , Japan , Mice , Chloroquine/pharmacology , Soil MicrobiologyABSTRACT
Two new pramanicin analogs, named virgaricins C (1) and D (2), were discovered by physicochemical screening from a static cultured material of Apiospora sp. FKI-8058. Their structures were elucidated by MS and NMR analyses and chemical derivatization. Compounds 1 and 2 showed moderate antimalarial activity and cytotoxicity.
