Absorption, distribution, elimination of tea polyphenols in rats.
Absorption, distribution, elimination of tea polyphenols in rats.
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发表时间：
1997
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通讯作者：
L. Chen;M. Lee;H. Li;C. S. Yang
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作者：
L. Chen;M. Lee;H. Li;C. S. Yang
茶多酚-包括（-）-表没食子儿茶素-3-没食子酸酯（EGCG）、（-）-表没食子儿茶素（EGC）和（-）-表儿茶素（EC）-被认为是茶的有益效果的原因。本研究旨在探讨大鼠饮用脱咖啡因绿色茶（DGT）后，EGCG、EGC和EC的吸收、分布和消除。为了比较，还研究了纯EGCG。通过HPLC定量血浆和组织中的EGCG、EGC和EC水平，并通过PCNONLIN程序分析结果。静脉注射DGT（25 mg/kg）后，EGCG、EGC和EC的血药浓度-时间曲线均符合二室模型。EGCG、EGC和EC的β消除半衰期（t1/2 β）分别为212、45和41 min;清除率分别为2.0、7.0和13.9 ml x min/kg，表观分布容积（V（d））分别为1.5、2.1和3.6 dl/kg。然而，当给予纯EGCG（10 mg/kg）时，观察到较短的t1/2 β（135 min），较大的清除率（72.5 ml x min/kg）和较大的V（d）（22.5 dl/kg），表明DGT中的其他成分可能影响EGCG的血浆浓度和消除。DGT（200 mg/kg）灌胃给药后，血浆中约有13.7%的EGC和31.2%的EC，但根据AUC（i.g.）/ AUC（i.v.）静脉注射DGT（25 mg/kg）后，肠道样本中表没食子酸酯基没食子酸酯（EGCG）水平最高，随后肠道中表没食子酸酯基没食子酸酯（EGCG）水平下降，t1/2为173 min。肾脏中表没食子酸酯（EGC）和内皮素（EC）水平最高，水平迅速下降，t1/2分别为29和28 min。EGCG在肠道中的AUC是肾脏中的4倍，但EGC和EC在肠道中的AUC与肾脏中的AUC相似。肝脏和肺中的EGCG、EGC和EC水平普遍低于肠和肾中的水平。结果表明，EGCG主要通过胆汁排泄，EGC和EC通过胆汁和尿液排泄。
Tea polyphenols-including (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC)-are believed to be responsible for the beneficial effects of tea. This study was conducted to investigate the absorption, distribution, and elimination of EGCG, EGC, and EC in rats after administration of decaffeinated green tea (DGT). For comparison, pure EGCG was also studied. The plasma and tissue levels of EGCG, EGC, and EC were quantified by HPLC, and the results were analyzed by the PCNONLIN program. Following intravenous injection of DGT (25 mg/kg), the plasma concentration-time curves of EGCG, EGC, and EC were fitted in a two-compartment model. The beta-elimination half-lives (t1/2beta) were 212, 45, and 41 min for EGCG, EGC, and EC, respectively; the clearances were 2.0, 7.0, and 13.9 ml x min/kg, and the apparent distribution volumes (V(d)) were 1.5, 2.1, and 3.6 dl/kg. When pure EGCG (10 mg/kg) was given, however, a shorter t1/2beta (135 min), a larger clearance (72.5 ml x min/kg), and a larger V(d) (22.5 dl/kg) for EGCG were observed, suggesting that other components in DGT could affect the plasma concentration and elimination of EGCG. After intragastric administration of DGT (200 mg/kg), approximately 13.7% of EGC and 31.2% of EC were shown in the plasma, but only 0.1% of EGCG was bioavailable as judged by the ratio of AUC(i.g.)/AUC(i.v.). After intravenous administration of DGT (25 mg/kg), the level of EGCG was found to be the highest in the intestine samples, and the intestinal EGCG level declined with a t1/2 of 173 min. The highest levels of EGC and EC were observed in the kidney, and the levels declined rapidly with t1/2 of 29 and 28 min, respectively. The AUC of EGCG in the intestine was 4-fold higher than that in the kidney, but the AUCs of EGC and EC in the intestine were similar to those in the kidney. The liver and lung levels of EGCG, EGC, and EC were generally lower than those in the intestine and the kidney. The distribution results suggest that EGCG is mainly excreted through bile, and that EGC and EC are excreted through both the bile and urine.