Planta Medica, 2006,
72 (10), p. 894-898 ISSN 0032-0943
A novel and very unusual azaanthracene alkaloid, 1-aza-7,8,9,10-tetra methoxy-4-methyl-2-oxo-1,2-dihydroanthracene (1) and a new diastereoisomer of the bis-benzylisoquinoline alkaloid rodiasine, 1S,1'R-rodiasine (2), as well as the alkaloids O-methylpunjabine (3) and O-methylmoschatoline (4) have been isolated from Pseudoxandra cuspidata bark, used in French Guiana as an antimalarial. Their structures were elucidated by spectroscopic analyses, especially 2D-NMR techniques (ADEQUATE and NOESY). We found that the antimalarial activity of this bark was mostly due to bis-benzylisoquinoline 1S 1'R-rodiasine (2) (IC50 = 1 mu M) also displaying a low cytotoxicity.
