1. LIQ. CHROM. & REL. TECHNOL., 24(15), 2283-2292 (2001) ASSAY OF FLAVONOLS AND QUANTIFICATION OF QUERCETIN IN MEDICINAL PLANTS BY HPLC WITH UV-DIODE ARRAY DETECTION M arin a Stefova,'> Svetl ana Kul evanova,' and Trajc e Stafilov ' I Instit ute of Chemistry, Faculty of Scie nce, P. O. Box 162, 1001 Sko pje, Republic of Macedonia , Institute of Pharmac ognosy, Faculty of Pharmacy, Vodnjanska 17, 1000 Skopje, Repub lic of Macedon ia ABS TRACT A new and rapid pro cedure for screening of flavonols (rnyrice tin, quercetin and kaernpferol) and for det erm ination of quercetin by RP- I-IP LC with UV-diode array detection in 16 medi- cinal plants is presented. Screening of the extrac ts showed that quercetin is the most abundan t flavonol, especially in Hyp erici herba , Uvae ursifol ium and Pruni spinosaejlos. Kaemp ferol was the most abundant in Rvbi niae pse udoaca ciae flos and Pruni spin- osaeflos, whereas myricetin was identified only in Betulae folium. The met hod for quant ification of quercetin was checked by the me thod of standard additions, and satisfac tory values for the recovery (97 .0- 103.5 %) were obtaine d. T he lim it of dete ct ion . was foun d to be 0.004 rng/mL and the limit of quantificat ion ' Corresponding author. E-mail: marinaiv@illnona.p mfukim.edll.mk 2283 Cop yrigh t © 200 1 by Marc e l Dekker . Inc. www .dekke r.com