Доклади на Българската академия на науките Comptes rendus de l’Acad´ emie bulgare des Sciences Tome 66, No 11, 2013 BIOLOGIE Botanique HPLC DETERMINATION OF PHENOLIC ACIDS IN ARNICAE FLOS Vessela Balabanova, Reneta Gevrenova, Dimitrina Zheleva-Dimitrova (Submitted by Academician V. Golemansky on June 25, 2013 ) Abstract The quantitative determination of protocatechuic, chlorogenic and caffeic acids in Arnica montana by reverse phase high-performance liquid chromatog- raphy (RP–HPLC) was carried out. Samples of Arnicae flos from eight different origins were selected for the assay as follows: one Bulgarian and one Polish culti- vated collection, two cultivars, three collections grown in the Botanical Garden in Finland and one is purchased from a Pharmacy Drugstore. The effect of extracting solvent was investigated and optimal extraction of assayed phenolic acids was achieved by 80% methanol. The subsequent HPLC separation of the analytes was performed on Hypersil ODS C 18 column using linear gradient elution with a mobile phase composed of 20 mM phosphate buffer (pH 3.22) and methanol, and with UV detection at 280 and 310 nm. The detection limits were 0.19 μg/ml, 0.51 μg/ml and 0.33 μg/ml for protocatechuic, chlorogenic and caffeic acids, respectively and the quantification limits were 0.57 μg/ml, 1.53 μg/ml and 0.99 μg/ml, respectively. Chlorogenic acid was the dominant phenolic acid in the studied samples being present in amounts between 0.68 ± 0.04 mg/g dry weight in the sample from Poland and 2.06 ± 0.17 mg/g in Arnicae flos collected from the Botanical Garden at Joensuu University, Finland. Caffeic and protocatechuic acids were detected in lower quantities. The caffeic acid was accounted for up to 0.16 ±0.08 mg/g dry weight in cultivar “ARBO” and it was lowest in the sample “Pharmacy Drugstore” – 0.02 ± 0.002 mg/g. The protocatechuic acid ranged from 0.01 ± 0.001 mg/g to 0.14 ± 0.01 mg/g. The results revealed that the sample from the Botanical Garden at Joen- suu University, Finland, tended to have the highest amounts of phenolic acids compared to the other samples, especially with cultivar “ARBO”. The Bulgar- ian collection is a promising source of valuable phenolic compounds. Key words: phenolic acids, Arnica montana, HPLC 1547