From the as yet unexplored East African Liana, Ancistrocladus robertsoniorum, several naphthylisoquinoline alkaloids have been isolated, based mainly on High Speed Countercurrent Chromatography (HSCCC). The structure of the new compound, ancistrobertsonine A, was elucidated by chemical and spectroscopic methods. Furthermore, the known alkaloids ancistrocladine, its atropo-diastereomer, hamatine, and its regioisomer, ancistrobrevine B, were isolated. (C) 1997 Elsevier Science Ltd.