Two new naphthalene glycosides from the seeds of Cassia obtusifolia

A phytochemical study on the seeds of Cassia obtusifolia was carried out, which finally led to obtain two naphthalenes (1 and 2), two naphthopyrans (3 and 4) and twelve anthraquinones (5-16). The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence. Among them, 1 and 2 (obtusinaphthalensides A and B) were identified to be new naphthalene glycosides.