Neonaucline, a New Indole Alkaloid from the Leaves of Ochreinauclea maingayii (Hook. f.) Ridsd. (Rubiaceae)

Abstract

A new indole alkaloid; neonaucline (1), along with six known compounds–Cadamine (2), naucledine (3), harmane, benzamide, cinnamide and blumenol A–were isolated from the leaves of Ochreinauclea maingayii (Rubiaceae). In addition to that of compound 1, 13C-NMR data of cadamine (2) and naucledine (3) were also reported. Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D- and 2D-NMR, IR, UV and LCMS-IT-TOF. The excellent vasorelaxant activity on isolated rat aorta was observed for the alkaloids 1–3 after injection of each sample at 1 × 10−5 M.

Keywords

• Ochreinauclea maingayii
• neonaucline
• nauledine
• cadamine
• Rubiaceae
• alkaloid