Plant. Strychnos ignatii Berg. ("S. cuspidata" form), stem bark. Source. Collected near mile 80 on the Sandakan-Labuk road, Sabah, Eastern Malaysia. Herbarium material under NO. SAN 53449 is deposited in the herbarium of the Forestry Department, Sandakan. The ground bark was basified with 10% NH4OH--20% aq. Na2CO3 (1:1) and extracted with CH2Cl2. After concentration of the extract, Et2O and a little CHCl3 were added and the bases taken into N-H2SO4, which after basification with cont. NH4OH was extracted repeatedly with CHCl3 and then with CHCl3-EtOH (3:2); yield of crude bases 12.2 + 2.9 g (1.49 + 0.35 = 1.84%). Check TLC of the alkaloids from the CHCl3 extracts indicated the presence of three groups of bases which were separated by silica-gel column chromatography: Group 1 alkaloids (ca 50% of the mixture), eluted with CHCl3-MeOH (24:1), were further separated by preparative TLC (system CH2Cl2-MeOH (99:1); run 20×) into pseudostrychnine and the main component pseudobrucine, both identified by comparison of the m.p.s, TLC and GLC properties, and IR spectra with those of authentic samples. Intermediate bands gave materials which were still mixtures and IR and MS evidence showed that N-cyano-sec.-pseudostrychnine and a little of a N-cyano-sec.-pseudobrucine were also present. Group 2 alkaloids (ca 35% of the mixture), eluted with CHCl3-MeOH (1:1), were likewise separated by preparative TLC (system CH2Cl2-MeOH (9:1); run 3×) into the components, which were further purified by passage through a small column of alumina and elution with C6H6-CHCl3 (1:1). The compounds were identified as strychnine and the main one as brucine, by comparison of the m.p.s, TLC and GLC properties, and IR spectra with those of authentic samples. Group 3 alkaloids (ca 15% of the mixture), eluted with MeOH and MeOH containing 2% H2SO4, were shown by TLC probably to include small amounts of strychnine and brucine N-oxides, but the greater part of this material evidently consisted of strychnine and brucine chlorometho-derivatives artefacts formed by the quaternization of strychnine and brucine with the CH2Cl2 used initially as extractant. No bases of the N-methyl-sec.-pseudo series were detected.