Potent Antiplasmodial Alkaloids and Flavonoids from Dasymaschalon acuminatum

A new aporphine alkaloid, 7-epi-duguetine (1) together with one known alkaloid, dicentrinone (2), and four known flavonoids, quercetin 3,7-dimethyl ether 3′ -O- α -L-rhamnopyranosyl-(1 g 2)-β-D-glucopyranoside (3), galangin 5-methyl ether (4), 5,7-dimethoxy-3-hydroxyflavone (5), and 3,5,7-trimethoxyflavone (6), were isolated from the leaves of Dasymaschalon acuminatum, a new plant species which has not been investigated phytochemically before. The structures of the isolated compounds were elucidated through extensive NMR spectroscopic analysis. All isolates were evaluated for antiplasmodial activity against Plasmodium falciparum strain K1 and 7- epi -duguetine was found to exhibit potent activity with an IC 50 of 0.385 m g/ml.