Cytotoxic guanidine alkaloids from Pterogyne nitens.

As part of a bioprospecting program aimed at the discovery of potential anticancer drugs, two new guanidine-type alkaloids, nitensidines D and E (1, 2), and the known pterogynine (3), pterogynidine (4), and galegine (5), were isolated from the leaves of Pterogyne nitens. The structures of 1 and 2 were established on the basis of spectroscopic data interpretation. These compounds were tested against a small panel of human cancer cell lines. Compound 2 exhibited cytotoxicity for HL-60 (human myeloblastic leukemia) and SF-245 (human glioblastoma) cells.