The components of the roots of Cassia obtusifolia L. were examined. As a result, nine anthraquinones [islandicin (1), helminthosporin (2), chrysophanol (3), physcion (4), xanthorin (5), 8-O-methylchrysophanol (8), obtusifolin (6), emodin (12), and aloe-emodin (14)], a naphtho-γ-pyrone [rubrofusarin (6)], a benzoquinone [2, 5-dimethoxybenzoquinone (11)], phytosterols (7), and betulinic acid (10) were isolated. Compounds 2, 8, 10, and 11 are new components from this plant.
Compounds 11 and 14 isolated from the roots and isotoralactone (22), toralactone (23), questin (15), and torosachrysone (24) from the seeds showed antimicrobial activities.