A chemical investigation of Sanango racemosum for the systematically useful iridoids and verbascosides has been performed. No iridoids could be detected, but verbascosides were shown to be present by high performance liquid chromatography and by nuclear magnetic resonance spectroscopy of the crude aqueous extract. Reversed phase chromatography provided two pure verbascosides, calceolarioside C and conandroside, as well as a new caffeic acid derivative which has been named sanangoside. The presence of verbascosides in Sanango, combined with the lack of iridoid glycosides, suggests affinity with the family Gesneriaceae. A closer chemical relationship with the Loganiaceae (Gentianales) is improbable.
A Re-Examination of Sanango racemosum. 3. Chemotaxonomy