Fractionation and chromatography of the acetone extract of the root bark of Citrus sinensis OSBECK var.brasiliensis TANAKA (Rutaceae) afforded three new acridone alkaloids namely citrusinine-I, -II and citbrasine and a new coumarin, ethylsuberenol. The structures of citrusinine-I -II, and citbrasine, and ethylsuberenol were characterized as la, 2a, 3, and 6, respectively. Citracridone-I (4), suberenol (7), suberosin (8), crenulatin (9), xanthoxyletin (10), xanthyletin (11), nordentatin (12), elemol (13), and p-hydroquinone were also isolated. © 1983, The Pharmaceutical Society of Japan. All rights reserved.