Petasitidis

Powdered drug (2g) is extracted by heating under reflux for about 20 min with about Farfarae folium, 40ml light petroleum on a water bath. The clear filtrate is concentrated to about 1 ml, Petasitidis folium and 30 pi is used for chromatography. (test for petasins)... 

Fig. I2C Methanoltc extracts of Farfarae folium (4) and the adulterant Petasitidis folium (5-7) have a very similar pattern of blue fluorescent phenol carboxylic acids. Flavonoid monoglycosides (R, range 0.5-0.65) are present in varying concentrations in Petasites species, while rutin is not detectable in the samples 5,6 and there are only traces in sample 7.

D For the detection of the sesquiterpenes e.g. petasol, neo- and isopetasol derivatives, a petrol ether extract has to be prepared. TLC development in CHClj and deteaion with concentrated ILSO., (98%) reveals the lipophilic compounds of Farfarae (4) and Petasitidis folium (5-7) as white-blue, red or green-blue zones over the whole R, range. The sesquiterpene petasiil/isopetasin are found in the R, range 0.4-0.45 as green-blue fluorescent zones. The concentration of the esters (e.g. methacryl petasol) varies, depending on the Petasites species. 

Petasites sample (7). shows the petasin/isopetasin as prominent zones, while in Petasitidis folium samples 5 and 6 the petasin is present in low concentration. Petasin-free chemical races also exist. In these cases Patasitidis and Farfarae folium extracts are hardly distinguishable. The red zones are due to furanoeremophilanes. 

CHCl, extracts of Petasitidis radix (8) show mostly blue fluorescent zones from the start up to the solvent front, due to more than 20 sesquiterpenes. 

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