Abstract
The occurrence of alkaloids in Rauwolfia caffra Sond. was investigated using thin layer chromatography and a colorimetric assay of the eluted
alkaloids. It was noted that the nitrous acid colorimetric assay devised by Szalkowski
and Mader (1956) yielded high results unrelated to pharmacological activity unless
the alkaloids were separated and estimated individually. The weakly basic alkaloids
are usually a minor component of the total alkaloids of R. caffra root, the principal alkaloids being ajmaline and raucaffricine.
