RESUMEN
From the methanolic extracts of solid callus cultures from two species of the closely related palaeotropical plant families Dioncophyllaceae and Ancistrocladaceae seven new natural naphthoquinones were isolated, dioncoquinones A (4) and B (5) from Triphyophyllum peltatum, and ancistroquinones B (6), C (7), D (9), E (10), and F (12) from Ancistrocladus abbreviatus. Their structures were elucidated by spectroscopic, chemical, and computational methods. Furthermore, the already known naphthoquinones plumbagin (2), droserone (3), malvone A (8), and nepenthone A (11) were found in the extract of A. abbreviatus. Dioncoquinones A (4) and B (5) showed good - and specific - activity against Leishmania major, while they were not active against other protozoic parasites. Moreover, treatment with 4 and 5 strongly induced apoptosis in human tumor cells derived from two different B cell malignancies, B cell lymphoma and multiple myeloma, without any significant toxicity towards normal peripheral mononuclear blood cells.