Three new 2-quinolinone alkaloids, zanthosimuline, huajiaosimuline, simulanoquinoline, along with nine known compounds, N-acetylanonaine, chelerythrine, norchelerythrine, bocconoline, 8-methoxy-N-methylflindersine, skimmianine, N-acetylnornuciferine, arnottianamide and decarine, were isolated and characterized from the root bark of Zanthoxylum simulans. The structures of theses compounds were elucidated by spectral analyses. Simulanoquinoline is the first naturally occurring dimeric alkaloid between dihydrobenzo[c]phenanthridine and 2-quinolone joined by a C-C linkage. © 1993.