Alkaloids from the leaves of Nauclea officinalis

To study chemical constituents of the leaves of Nauclea officinalis, eight alkaloids were isolated from 95% ethanol extract by various chromatographic methods.  The structures were elucidated on the basis of spectroscopic data (IR, UV, ESI-MS, 1D and 2D NMR) and identified as naucleactonin C (1), strictosamide (2), vincosamide (3), pumiloside (4), angustoline (5), angustine (6), 18, 19-dihydroangustine (7) and naucleofficine D (8).  Compound 1 is a new indole alkaloid.  Compounds 6 and 7 were isolated from this plant for the first time.