Five anhydronium bases were isolated by preparative HPLC from a methanolic extract of Rauvolfia serpentina roots. For the first time 3,4,5,6-tetradehydroyohimbine, 3,4,5,6-tetradehydro-(Z)-geissoschizol, 3,4,5,6-tetradehydrogeissoschizol and 3,4,5,6-tetra-dehydrogeissoschizine-17-O-beta-D-glucopyranoside were isolated from a natural source. In addition, the well-known anhydronium base serpentine was isolated. The structures of the compounds were determined by H-1 and C-13 NMR, MS and UV. (C) 2002 Elsevier Science Ltd. All rights reserved.