title: Antioxidative effect of polyphenol extract prepared from various Chinese teas.
abstract: METHODS. Twelve different types of Chinese teas, including green, semifermented, and black tea, were studied for their antioxidant activities and active components. Compositions of (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate, and gallic acid were identified by fast atom bombardment-mass spectrometry and high-performance liquid chromatography-mass spectrometry and quantified by high-performance liquid chromatography. Antioxidant activities in lard were measured by the Rancimat method. RESULTS. The results showed that both yields of polyphenol extract and antioxidant activities varied with different tea processing methods. It was found that (-)-epigallocatechin gallate, (-)-epigallocatechin, and (-)-epicatechin gallate inhibited soybean lipoxygenase at the IC50 values ranging from 10 to 20 microM.
authors.affiliation: Department of Food Science, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903.
authors.forename: C T
authors.initials: CT
authors.lastname: Ho
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
authors.forename: H
authors.initials: H
authors.lastname: Shi
authors.forename: K Q
authors.initials: KQ
authors.lastname: Zhang
authors.forename: R T
authors.initials: RT
authors.lastname: Rosen
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005419:Flavonoids; D050356:Lipid Metabolism; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013552:Swine; D013662:Tea
chemical_list: D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D013662:Tea