Two new cytotoxic isomeric indole alkaloids from the roots of Nauclea orientalis

A pair of new isomeric indole alkaloids, naucleaorals A (1) and B (2) were isolated from the roots of Nauclea orientalis. The structures of compounds 1 and 2 were fully characterized using spectroscopic data, and were tested for their cytotoxicity (HeLa and KB cells) and antimalarial activity. Compound 1 showed significant cytotoxicity to HeLa cells with an IC50 value of 4.0 mu g/mL, while compound 2 exhibited very modest cytotoxicity to both cell lines with IC50 values of 7.8 and 9.5 mu g/mL, respectively. Both compounds proved to be inactive in antimalarial assays (IC50>10.00 mu g/mL). (C) 2010 Elsevier B.V. All rights reserved.