title: Presence of two forms of methylated (-)-epigallocatechin-3-gallate in green tea.
abstract: Crude catechins extract from Chinese green tea were fractionated using Sephadex LH-20 column chromatography. The fraction containing (-)-epigallocatechin-3-gallate (EGCG) was then subjected to a semipreparative high-performance liquid chromatography (HPLC). Using a mobile phase of water: dimethyl formamide: methanol: acetic acid (157:49:2:1 v/v/v/v), the mixture of two methylated catechins was separated and isolated. According to mass spectrometry (MS) and nuclear magnetic resonance ('H-NMR) date, these compounds were identified as (-)-epigallocatechin-3-(3-O-methylgallate) and (-)-epigallocatechin-3-(4-O-methylgallate).
authors.affiliation: Division of Food Science, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Alsztyn, Poland. amaro@pan.olsztyn.pl
authors.forename: Ryszard
authors.initials: R
authors.lastname: Amarowicz
authors.forename: Fereidoon
authors.initials: F
authors.lastname: Shahidi
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate