Extraction of Epigallocatechin Gallate and Epicatechin Gallate from Tea Leaves Using -Cyclodextrin

Use of organic solvents to extract phenolic compounds from plants may result in environmental pollution and cause health problems in persons. Replacing organic extraction solvents by green extracting agents without affecting the extraction yield is one of the most pressing problems to be solved. The aim of this study is to evaluate the capacity of -cyclodextrin (-CD) to recover phenolic compounds from tea leaves. The extract obtained using the ethanol/water mixture presented the highest total phenolic content, followed by those obtained using -CD solution and water. HPLC analysis of the extracts showed that the addition of -CD to the extracting agent had a selective effect on the extraction of epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The extraction yield of EGCG and ECG using 15 g/L -CD were higher than that obtained using water and 50% ethanol. Molecular docking results indicated that the molecules of EGCG and ECG were more inclined to interact with -CD than epigallocatechin, epicatechin, and gallocatechin. The impact of -CD concentration, temperature, and time on EGCG and ECG extraction from tea leaves was investigated and the maximum amount of EGCG (118.7 mg/g) and ECG (54.6 mg/g) were achieved when extracted with 25 g/L aqueous -CD solution at 60 degrees C for 60 min. The present study indicates that aqueous -CD can be used as an alternative to organic solvents to recover EGCG and ECG from tea leaves. Practical Application Tea catechins have recently received much attention due to their health benefits and functionality and have been widely used in pharmaceuticals, nutraceuticals, and cosmetics. The extraction of catechins is the 1st step for their further use. Generally, organic solvents are used to recover phenolic compounds from plants. However, use of organic solvents may result in environmental pollution and cause health problems in persons. This study has proved that -CD has the potential to replace organic solvents to extract EGCG and ECG from tea leaves.