Indoloquinazoline alkaloids from <i>Araliopsis tabouensis</i>

Abstract

Three new indoloquinazolidine-type alkaloids, 2-methoxy-8-13-dihydro-7H-indolo[pyrido[2,1-b]quinazolin-5-one (1) , 2-methoxy-13-methyl-8-13-dihydro-7H-indolo[2',3',3,4]pyrido[2,1-b]quinazolin-5-one (2) , and 2-methoxy-14-methyl-7,8,13,14-tetrahydroindolo[2',3',4]pyrido[2,l-b]quinazolin-5-one (3) were isolated from Araliopsis tabouensis, together with three known compounds. The structures of the new compounds were determined primarily from 1D- and 2D-NMR spectroscopy. The antimalarial activities of compounds 1-5 were evaluated against Plasmodium falciparum D6 and W2 clones. The IC₅₀ values in antimalarial bioassay for compounds 2-5 varied from 1.8 to 4.7 μg/ml.

Nig. J. Pharm. Res. 3(1) 2004: 42-48