engleski

Application of low-temperature eutectic solvents in the extraction of ellagitannins and phenolic acids from Alchemilla vulgaris

Due to the growing use of bioactive components in the food and in the pharmaceutical industry, rapid development of various methods for their extraction and separation is required. In the last few years, deep eutectic solvents (DESs), composed of a hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) components, stand out as an appropriate substitution to conventional solvents due to their properties, with emphasis on non- toxicity, thermal stability and biodegradability, with easy preparation and low price of components. Alchemilla vulgaris L. is a plant that is often used in folk medicine as it possesses numerous health-promoting benefits due to its specific chemical composition with emphasis on phenolic acids and elagitannins. The most important components with antioxidant activity in sage are phenolic acids, such as gallic and ellagic acid as well as elagitannins which can be extracted by various extraction techniques, most commonly solid-liquid extraction. The aim of this paper was to select the most suitable choline chloride based deep eutectic solvent for the extraction of gallic and ellagic acid as well as elagitannins from lady's mantle (Alchemilla vulgaris L.) and then optimize extraction conditions for extraction with stirring and heating, ultrasound-assisted extraction and mechanoextraction. Seventeen different choline chloride-based DESs with different volumes of water (10%, 30%, and 50% (v/v)) were used for the extraction at different temperatures (30, 50, and 70 °C) to investigate the influence on this extraction parameters on yield of desired components. The results obtained were compared with the results obtained by extraction with conventional solvents. Gallic and ellagic acid content was obtained by high- performance liquid chromatography with diode-array detector (HPLC- DAD) and total ellagitannins were determined spectrophotometrically in the obtained extracts. Screening revealed that among 17 different DESs, the most suitable solvent is choline chloride: urea (1:2) and the most suitable extraction technique is extraction with stirring and heating. According to the results, the prepared solvents prove to be a good substitute for organic solvents in the extraction of bioactive components from lady's mantle plant.

deep eutectic solvents ; extraction ; ellagitannins ; optimization ; RSM

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