Analysis of active components from different ages of old Wuyi rock tea by gradient extraction

In this study, a comparative analysis of the extraction yields of flavonoids, polyphenols, and terpenes from aged Wuyi rock tea of different years in solvents such as petroleum ether, dichloromethane, ethyl acetate, n-butanol, and water was conducted, which provides a theoretical basis for the separation and purification of active components. A 75% ethanol reflux extraction method was employed to prepare the ethanol extract, followed by extraction of the aqueous suspension using different polar organic solvents and deep eutectic solvents. The contents were determined by UV spectrophotometry. The results showed that the total extraction yields of flavonoids and polyphenols varied with the solvents, in the order of n-butanol, ethyl acetate, water, dichloromethane, and petroleum ether; for triterpenoids, the order was n-butanol, water, petroleum ether, ethyl acetate, and dichloromethane. N-butanol was identified as the optimal solvent. This study also detected a flavonoid compound, presumably glycyrrhizic acid, based on comparisons with existing literature and information. Currently, research and development on flavonoids, polyphenols, and triterpenoids in aged tea are underway, aiming to further explore the value and application potential of tea and contribute to the development of the tea industry.