Novel Naphthoquinone Derivatives from the Roots of Rhinacanthus nasutus Kurz and Their Biological Activities in Vitro

摘要

Rhinacanthus nasutus Kurz. (Acanthaceae) has been used as Taiwanese traditional medicine for the treatment of various diseases including cancer. The six new naphthoquinone analogues along with thirteen known compounds were isolated from the 90% ethanol extract of the root of R. nasutus Kurz. Their structures were determined by using ID, 2D and MS spectroscopic methods. All of isolated new compounds showed cytotoxic activity against cancer cell lines, HL-60, THP-1 and Jurkat cells, with their IC50 values at about 3-40 [ig/mL. Further, the anti-adipogenesis activities on the isolated compounds and the extract in rat white preadipocytes (RWPA) were also investigated in vitro. An administration of the aqueous EtOH extracts ofR nasutus inhibited the adipogenesis in cultured RWPA in a concentration-dependent manner. Among the isolated naphthoquinones, cumulative lipogenesis was reduced by the five known rhinacanthins (A (1),C (3)， D (4), E (5) and Q (11)) or new compound14 (naphth [1,2-b] oxepin-3-methanol, 2,3-dihydro-3-hydroxy-7-methoxy) at10 |ig/mL. These activities were accompanied the cytotoxicities, whereas the new14 did reduced lipogenesis without any significant cytotoxicity against RWPA at higher. These observations suggested that the Taiwanese herbal medicine R. nasutus might be a beneficial not only for health food but also for finding source of the lead compounds especially for anti-cancer or anti-obesity agents.