Structural Identification of Two Metabolites of Catechins and Their Kinetics in Human Urine and Blood after Tea Ingestion
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- 作者：Chuan Li ; Mao-Jung Lee ; Shuqun Sheng ; Xiaofeng Meng ; Saileta Prabhu ; Bozena Winnik ; Baoming Huang ; Jee Y. Chung ; Shunqi Yan ; Chi-Tang Ho ; and Chung S. Yang
- 刊名：Chemical Research in Toxicology
- 出版年：2000
- 出版时间：March 2000
- 年：2000
- 卷：13
- 期：3
- 页码：177 - 184
- 全文大小：209K
- 年卷期：v.13,no.3(March 2000)
- ISSN：1520-5010
文摘
Tea is a popular beverage consumed worldwide. The metabolic fate of its major constituents,catechins, however, is not well-known. In this study, two catechin metabolites were detectedin the urine and plasma of human volunteers after ingestion of green tea. These metaboliteswere identified by LC/ESI-MS and NMR as (-)-5-(3',4',5'-trihydroxyphenyl)-
-valerolactone(M4) and (-)-5-(3',4'-dihydroxyphenyl)--valerolactone (M6). The renal excretion of M4 andM6 had a 3 h lag time and peaked 7.5-13.5 h after ingestion of a single dose of green tea,while (-)-epigallocatechin (EGC) and (-)-epicatechin peaked at 2 h. M4 and M6 were twomajor tea metabolites with urinary cumulative excretions as high as 8-25 times the levels ofEGC and (-)-epicatechin in some of our subjects, and accounted for 6-39% of the amounts ofingested EGC and (-)-epicatechin. Both the metabolites appeared to be produced by intestinalmicroorganisms, with EGC and (-)-epicatechin as the precursors of M4 and M6, respectively.Repeated ingestion of green tea produced a slight accumulative effect of the metabolites. Theywere also detected in the plasma, exhibiting kinetics similar to those of the urinary metabolites,and in the feces. Study on these metabolites may help us further understand the cancerchemopreventive actions and other beneficial effects of tea.
-valerolactone(M4) and (-)-5-(3',4'-dihydroxyphenyl)--valerolactone (M6). The renal excretion of M4 andM6 had a 3 h lag time and peaked 7.5-13.5 h after ingestion of a single dose of green tea,while (-)-epigallocatechin (EGC) and (-)-epicatechin peaked at 2 h. M4 and M6 were twomajor tea metabolites with urinary cumulative excretions as high as 8-25 times the levels ofEGC and (-)-epicatechin in some of our subjects, and accounted for 6-39% of the amounts ofingested EGC and (-)-epicatechin. Both the metabolites appeared to be produced by intestinalmicroorganisms, with EGC and (-)-epicatechin as the precursors of M4 and M6, respectively.Repeated ingestion of green tea produced a slight accumulative effect of the metabolites. Theywere also detected in the plasma, exhibiting kinetics similar to those of the urinary metabolites,and in the feces. Study on these metabolites may help us further understand the cancerchemopreventive actions and other beneficial effects of tea.