The dried rhizome of Pelargonium sidoides contains at least eight different coumarins, of which umckalin and 5,6,7-methoxycoumarin are considered as useful marker compounds. The herb also contains antioxidants such as gallic acids and methyl esters of gallic acids, as well as flavonoids (quercetin), flavan-3-ols (catechin, gallo-catechin) and phytosterols (sitosterol-3-gluoside).

 Umckalin and Scopoletin chemical structure

In addition, there is much divergence in concentration, with significantly higher yields of coumarins in P. sidoides than in other Pelargonium species. The total coumarin content of the roots of P. sidoides is approximately 0.05% related to dry weight, with umckalin contributing approximately 40% of total coumarin content.

HPLC Assay of Umckalin in Afriplex PS70™ 

HPLC Assay of Umckalin in Afriplex®PS70.

TLC testing the stability of the analyte Scopoletin.