Corypalmine (or (-)-corypalmine) is an alkaloid which has been isolated from the crude base fraction of Corydalis chaerophylla and can inhibit prolyl oligopeptidase, an enzyme that hydrolyzes proline-containing peptides at the carboxy terminus of proline residues. It has been associated with schizophrenia, bipolar affective disorder, and related neuropsychiatric disorders and therefore may have important clinical implications.