No 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.

Ipecacuanha is the Portugese name derived from the Brazilian-Indian "ipe-kasguene"a creeping plant causing vomitting. The use of the plant as a drug by the South American Indians was first recorded in 1601 by a Jesuit F r i a r . The drug was introduced into Britain by G r a s in 1672 ( C l a u s and T y 1 e r , 1965).The British Pharmacopoeia 1968 recognises two species, Cephaelis ipecacuanha (Rio or Brazilian ipecacuanha) and Cephaelis acuminata (Cartagena, Nicaragua or Panama ipecacuanha). The Costa Rica variety, derived from C. acuminata, is widely used in commerce and is named by the British Pharmaceutical Codex 1968.Titrimetric methods are commonly used for the estimation of the total alkaloid content, calculated as emetine (B r i ti s h P h a r m a c o p o e i a , 1968). Formerly a