Three new nitrogen-containing heterocyclic alkaloids, oryzamutaic acids H-J (1-3), were isolated from the endosperm (polished rice) of an Oryza sativa mutant. The structures and relative stereochemistries of 1-3 were elucidated on the basis of spectroscopic analyses. The presence of three carbons, each bound to a carboxyl group and a nitrogen atom in the structure of 1, suggests that oryzamutaic acids H-J (1-3) are generated from three molecules of a single amino acid. © 2010 Elsevier Ltd. All rights reserved.