Subcritical Water Extraction of Epigallocatechin Gallate from Camellia sinensis and Optimization Study Using Response Surface Methodology

Abstract

Background: Camellia sinensis is a plant whose leaves and buds are used to produce tea. With many medicinal activities already found, green tea has been consumed widely in the world. Methods: The subcritical water extraction (SWE) of epigallocatechin gallate (EGCG) from green tea leaves and the effect of the different extraction conditions are investigated by response surface methodology (RSM). Furthermore, the model of the extraction processes is reviewed for application at the industrial scale. Results: Based on the RSM data, the maximum yield of extraction is determined via optimizing different parameters of the extraction processes. Optimal conditions are as follows: extraction time of 6 min, extraction temperature at 120 °C, and a sample/solvent ratio of 1:40 g/mL. Under such conditions, the best yield of EGCG is 4.665%. Moreover, the model of the extraction processes, which can be utilized for industry scale purpose, indicates a good correlation with the experimental data. Conclusions: Overall, SWE is competent and environmental-friendly, and it is also a highly selective and fast method. SWE is a promising method to take the place of organic solvents used in the extraction of weak polar and even non-polar natural compounds. Further studies on the scale-up of the extraction processes are ongoing.

Subcritical Water Extraction of Natural Products

“…Plants extracted by subcritical water mainly include herbs [ 15 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], vegetables with medicinal values [ 30 , 31 ], fruits [ 32 , 33 , 34 , 35 , 36 ], oilseed crops [ 37 , 38 , 39 , 40 ], shrubs, grains, tea leaves and beans [ 41 , 42 , 43 , 44 , 45 , 46 ]. These plants have been used in traditional medicine for thousands of years in some countries and have been proved to possess plentiful pharmacologically active components.…”

Plant-Derived Natural Products in Cancer Research: Extraction, Mechanism of Action, and Drug Formulation

“…Modulation conditions of the ultrasound-assisted extraction method have optimized the extracted amount of EGCG from lipid extracted microalgae [72]. Moreover, subcritical water extraction of EGCG from green tea has been applied with adjusted extraction parameters resulted in a 4.66% yield of EGCG [73]. The extraction efficiency of epigallocatechin gallate was improved by using electrochemical methods.…”

Hot Water Extraction of Antioxidants from Tea Leaves—Optimization of Brewing Conditions for Preparing Antioxidant-Rich Tea Drinks

“…The health benefits of tea drinks have also been discussed [ 11 ]. Various extraction techniques have been employed to extract the antioxidants from tea leaves [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. They include subcritical water extraction [ 16 ], pressurized hot water extraction (the same as subcritical water extraction) [ 15 ], microwave-assisted extraction [ 19 ], and cold and hot water extraction [ 17 ].…”