The Influence of Water Extraction Methods on the Isolation of Polyphenols and Tannins from Various Ericaceae and Rosaceae Species.

Most polyphenols (and tannins in their composition), secondary plant metabolites with positive effects on the human body, are soluble in water, which makes them environmentally friendly and the most accessible solvent in everyday life. The aim of this study was to examine the effects of water extraction methods, hot water extraction and maceration, on the amounts of these compounds isolated from plants, compared with ultrasonic extraction, which is not readily available. Seven Ericaceae and four Rosaceae species were selected for study, whose leaves are used in folk and/or official medicine to make herbal teas. Total polyphenolics were determined by the Folin-Ciocalteu method spectrophotometrically and total tannins by calculating the difference between the total and remaining polyphenolic content after tannin precipitation. The results demonstrated that ultrasound was not the most effective method for extracting polyphenols: it yielded the highest polyphenol amounts only from two Rosaceae species, Potentilla anserina and Alchemilla vulgaris. The hot water extraction of polyphenols was more effective than maceration. Hot water was more effective in extracting polyphenols from evergreen plants. Regardless of the extraction method, most of the polyphenols were extracted with water from Arctostaphylos uva-ursi and tannins from Rhododendron tomentosum leaves. The studied Ericaceae species accumulate higher-polarity tannins than the studied Rosaceae representatives.