Extraction of polyphenols from dried tea leaves

摘要: Polyphenols, a group of compounds present in tea leaves as major constituent, is known for its antioxidant property. It was extracted from dried and ground tea leaves. Enzymes in the fresh tea leaves were deactivated prior to drying followed by grinding and sieving. Caffeine, the other pharmacologically important compound, was also extracted as a byproduct. Crude extraction was made with water and subsequently the extract was concentrated for decaffeination with 1, 2-Dichloromethane. Polyphenols were extracted from the decaffeinated crude extract with ethyl acetate. Ethyl acetate was removed from the extract to get dry solid polyphenols. Total polyphenols in the product was estimated by UV-Vis using Folin-Ciocalteu Phenol reagent, methods as described in ISO/DIS 14502-1. Catechins, the major component of tea polyphenols, were analysed by High Performance Liquid Chromatography (HPLC) for individual catechin present, as described ISO/CD 14502-2.