Reference

Production and HPLC analysis of black tea theaflavins and thearubigins during in vitro oxidation

Production and HPLC analysis of black tea theaflavins and thearubigins during in vitro oxidation. Robertson, Alastair; Bendall, Derek S. (Dep. Biochem., Univ. Cambridge, Cambridge, UK). Phytochemistry, 22(4), 883-7 (English) 1983. CODEN: PYTCAS.Chemicals with cas numbers 12698-96-3 and 4670-05-7 also play role. ISSN: 0031-9422. DOCUMENT TYPE: Journal CA Section: 17 (Food and Feed Chemistry) A model fermn. system was designed which utilized pure catechins and partially purified polyphenol oxidase (EC 1.14.18.1) from green tea shoots. High-performance liq. chromatog. (HPLC) anal. of the products formed during in vitro oxidn. demonstrated a close similarity between this system and in vivo oxidn. occurring during factory fermn. Changes in theaflavin [4670-05-7] and thearubigin [12698-96-3] levels, revealed by time courses of fermn., showed in vitro and in vivo systems to be qual. similar, although the former system produced considerably higher levels of both components. The model fermn. system, therefore, appears to be a suitable exptl. system for studying the formation of theaflavin and thearubigin pigments under strictly controlled conditions. In preliminary expts. the theaflavins were identified on HPlC profiles by enzymic oxidn. of the relevant catechin pairs. Similarly, major colored components other than theaflavins, which are considered to be thearubigins, were formed by the oxidn. and reaction of two gallocatechins (epigallocatechin [970-74-1] and epigallocatechin gallate) [989-51-5]. The model fermn. system, in conjunction with HPLC as described in this paper, provides a means whereby precise data on theaflavin and thearubigin formation can be obtained and, in the case of the thearubigins, one could yield addnl. structural information. .

Effects of crude drugs on experimental hypercholesterolemia

Effects of crude drugs on experimental hypercholesterolemia. I. Tea and its active principles. Matsuda, Hisashi; Chisaka, Takeshi; Kubomura, Yasushi; Yamahara, Johji; Sawada, Tokunosuke; Fujimura, Hajime; Kimura, Hitoshi (Kyoto Pharm. Univ., Kyoto 607, Japan). J. Ethnopharmacol., 17(3), 213-24 (English) 1986. CODEN: JOETD7. ISSN: 0378-8741. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 17 The effect of MeOH exts. from tea leaves on hypercholesterolemia was examd. in mouse models. Orally administered (-)-epicatechin gallate [1257-08-5] and (-)-epigallocatechin gallate [989-51-5] from tea leaves lowered the serum cholesterol level in mice fed a high-fat emulsion. Quantitation of tissue cholesterol and examn. of liver tissues in mice fed a high-cholesterol diet revealed that these constituents also significantly lowered the amt. of cholesterol crystn. These results support the reputed effectiveness of tea against hypercholesterolemia.