A novel azafluoranthene alkaloid, norimeluteine, has been isolated as a cytotoxic substance from Cissampelos pareira (Menispermaceae), together with an alkaloid having the same skeleton, norruffscine. Carbon-13 nuclear magnetic resonance assignments for the azafluoranthene alkaloids were performed by a combination of two dimentional NMR techniques. © 1993, The Pharmaceutical Society of Japan. All rights reserved.