Planta Med 2009; 75 - PG39
DOI: 10.1055/s-0029-1234693

Development of HPTLC densitometric method for analysis of lycopsamine in comfrey (Symphytum officinale L.) using retrorsine as a reference compound

D Janeš 1, S Kreft 1
  • 1University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia

Comfrey (Symphytum officinale L.) has been used topically for treating inflammatory disorders such as arthritis, gout and thrombophlebitis and internally for treating diarrhoea. Apart of allantoin and other constituents, which are considered to have therapeutic effect, it also contains toxic pyrrolizidine alkaloids (mainly lycopsamine, intermedine, their acetylated derivatives and symphytine). Because of their high toxicity it is of interest to determine these alkaloids in medicinal products even at low concentrations [1,2]. Unfortunately, many reference compounds of pyrrolizidine alkaloids are not commercially available [3]. Commercially available alkaloids may be used as reference compounds, but they must be standardised against marker alkaloids, which are actually present in the plant. Therefore, lycopsamine was isolated from comfrey roots and employed together with commercially available retrorsine for development of a high performance thin layer chromatography (HPTLC) method for quantitative densitometric analysis of pyrrolizidine alkaloids after derivatisation with Dann-Mattocks reagent. The method was validated according to ICH directives. It proved to be linear within 0.7 to 7.0mg of lycopsamine per application of a sample. The mass factor retrorsine/lycopsamine was 1.18 (calculated with height of peaks) and 0.98 (calculated with area under curve). The method also proved to be specific and to have good repeatability (with RSD 2–4% within the plate).

References: [1] DerMarderosian, A. et al. (2006) The Review of Natural Products: Comfrey. Wolters Kluwer Health. St. Luis, MO.

[2] Wichtl, M. (2009) Teedrogen und Phytopharmaka (5th ed.). Wissenschaftliche Verlagsgesellschaft mbH. Stuttgart, Germany.

[3] Wuilloud, J.C. et al. (2004) Analyst 129:150–156.