Assay of flavonols and quantification of quercetin in medicinal plants by HPLC with UV-diode array detection

A new and rapid procedure for screening of flavonols (myricetin, quercetin and kaempferol) and for determination of quercetin by RP-HPLC with UV-diode array detection in 16 medicinal plants is presented. Screening of the extr acts showed that quercetin is the most abundant flavonol, especially in Hyp erici herba, Uvae ursi folium and Pruni spinosae flos. Kaempferol was the m ost abundant in Robiniae pseudoacaciae flos and Pruni spinosae flos, wherea s myricetin was identified only in Betulae folium. The method for quantification of quercetin was checked by the method of sta ndard additions, and satisfactory values for the recovery (97.0-103.5 %) we re obtained. The limit of detection was found to be 0.004 mg/mL and the lim it of quantification 0.013 mg/mL of quercetin. The content of quercetin in the plant material ranged from 0.026-0.552 % (m/m).