Extraction methods for the determination of phenolic compounds from Equisetum arvense L. herb

Polyphenols are a very important group of pharmacologically active compounds. The extraction yield of selected phenolic acids and flavonoids from Equisetum arvense L. herb has been determined by use different methods of extraction - Soxhlet extraction, ultrasound assisted extraction (USAE), and accelerated solvent extraction (ASE). Methanol and 80% aqueous methanol were used as extractants. The crude extracts were evaporated to dryness and prepared for fractionation of the analyzed compounds by solid-phase extraction (SPE). An alternative method used for the isolation and purification of analyzed polyphenols was matrix solid-phase dispersion (MSPD). Samples containing the phenolic fraction were analyzed by RP-HPLC. Quantitative analysis was performed by the external standard method and use of a calibration plot for each standard. The most effective technique was ultrasound assisted extraction. Only for caffeic acid the highest yield gave exhaustive extraction in a Soxhlet apparatus. The methods were validated in terms of accuracy, precision LOD and LOQ. (C) 2014 Elsevier B.V. All rights reserved.