Costinones A (1) and B (2), the new oxindole alkaloids have been isolated from Isatis costata along with indirubin (3). Their structures have been assigned on the basis of spaectroscopic data. Both the compounds inhibited lipoxygenase and butyrylcholinesterase enzymes non-competitively in concentration-dependent fashion with promising inhibitory potentials. © 2006 The Japan Institute of Heterocyclic Chemistry All rights reserved.