Characterization of calendula flower, milk-thistle fruit, and passion flower tinctures by HPLC-DAD and HPLC-MS

As a part of an investigation of the content of herbal drug preparations an d herbal medicinal products, we have investigated tinctures (prepared with 40:60 and 60:40 (%, v/v) ethanol-water) of calendula flower, milk-thistle f ruit, and passion flower, which are, respectively, widely used for their an ti-inflammatory properties, to treat hepatic injuries, and to treat tension and difficulty falling asleep, The aim of this work was to evaluate the fl avonoid content, because flavonoids are the active constituents or markers of these herbal drugs, and to establish the best solvent for the extraction of the constituents. The findings reported herein both confirm the presenc e of several flavonoids previously identified in these herbal drugs and rep ort the presence of others not previously described and identified here for the first time. In general the flavonol content was highest in 60% tinctur es. A rapid, reversed-phase (RP) HPLC assay was developed and validated and enabled good separation of all classes of flavonoids including flavones, f lavonols, flavanonols, and flavanolignans. Aglycones and mono, di, and trig lycosides (both O-and C-derivatives) of the flavonoids are also easily and satisfactorily separated. This method is thus proposed for the analysis of other herbal drugs or herbal drug preparations in which flavonoids are the active constituents or markers.