Bioactivity-guided fractionation of a methanolic CHCl3 extract of the
leaves of Pterogyne nitens afforded the known guanidine alkaloid ptero
gynidine (2) and three new guanidine alkaloids, nitensidines A (3), B
(4), and C (5), all of which exhibited selective activity towards the
DNA repair-deficient yeast mutant RS 321 (IC12 = 9.3 - 20.0 mu g/ml);
3,4, and 5 were moderately cytotoxic to CHO Aux B-1 cells (IC50 = 8.5
- 13.0 mu g/ml).