ABSTRACT
Pentas micrantha is used in the East African indigenous medicine to treat malaria. In the first investigation of this plant, the crude methanol root extract showed moderate antiplasmodial activity against the W2- (3.37 µg/mL) and D6-strains (4.00 µg/mL) of Plasmodium falciparum and low cytotoxicity (>450 µg/mL, MCF-7 cell line). Chromatographic separation of the extract yielded nine anthraquinones, of which 5,6-dihydroxylucidin-11-O-methyl ether is new. Isolation of a munjistin derivative from the genus Pentas is reported here for the first time. The isolated constituents were identified by NMR and mass spectrometric techniques and showed low antiplasmodial activities.
Subject(s)
Anthraquinones/pharmacology , Antimalarials/pharmacology , Plant Extracts/pharmacology , Plant Roots/chemistry , Rubiaceae/chemistry , Anthraquinones/isolation & purification , Antimalarials/isolation & purification , Drug Resistance , Magnetic Resonance Spectroscopy , Malaria/drug therapy , Plant Extracts/isolation & purification , Plasmodium falciparum/drug effects , Plasmodium falciparum/growth & developmentABSTRACT
Four new naphthohydroquinones, named busseihydroquinones A-D (1-4), along with a known homoprenylated dihydronaphthoquinone (5), were isolated from the CH(2)Cl(2)/MeOH (1:1) extract of the roots of Pentas bussei. Although the genus Pentas is frequently used by traditional healers for the treatment of malaria, only marginal activities against the chloroquine-sensitive (D6) and the chloroquine-resistant (W2) strains of Plasmodium falciparum were observed for the crude root extract and the isolated constituents of this plant.
