National Institute of Vegetable and Tea Sciences, National Agriculture and Food Research Organization, 2769 Kanaya-Shishidoi, Shimada, Shizuoka, 428-8501, Japan,
Cytotechnology. 2011 Mar;63(2):171-9. doi: 10.1007/s10616-010-9331-8. Epub 2011 Jan 5.
Tea polyphenols, e.g., (-)-epigallocatechin-3-O-(3-O-methyl gallate (EGCG3"Me), (-)-epigallocatechin-3-O-gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin-3-O-gallate (ECG), and (-)-epicatechin (EC), are believed to be responsible for the beneficial effects of tea. 'Benifuuki', a tea (Camellia sinensis L.) cultivar grown in Japan, is rich in the anti-allergic molecule epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3"Me). Pulverized Benifuuki green tea powder (BGP) is more widely distributed than leaf tea in Japan. Japanese people mix their pulverized tea with water directly, whereas it is common to drink leaf tea after extraction. However, few studies of the effects of BGP particle size on polyphenol bioavailability have been performed. This study was conducted to investigate the absorption of catechins in rats after the intragastric administration of Benifuuki green tea. Therefore, we assessed the plasma concentrations of catechins following the ingestion of BGP with different mean particle sizes (2.86, 18.6, and 76.1 μm) or Benifuuki green tea infusion (BGI) as a control in rats. The bioavailabilities of EGCG3"Me, EGCG, ECG, EGC, and EC were analyzed after the oral administration of a single dose of Benifuuki green tea (125 mg/rat) to rats. The plasma concentrations of tea catechins were determined by HPLC analysis combined with of electrochemical detection (ECD) using a coulometric array. The AUC (area under the drug concentration versus time curve; min μg/mL) of ester-type catechins (EGCG3"Me, EGCG, and ECG) for the BGP 2.86 μm were significantly higher than those in the infusion and 18.6 and 76.1 μm BGP groups, but the AUC of free-type catechins (EGC and EC) showed no differences between these groups. Regarding the peak plasma level of EGCG3"Me adjusted for intake, BGP 2.86 μm and BGI showed higher values than the BGP 18.6 and 76.1 μm groups, and the peak plasma levels of the other catechins displayed the same tendency. The present study demonstrates that the bioavailability of ester-type catechins (EGCG and ECG) can be improved by reducing the particle size of green tea, but the plasma level of EGCG3"Me in the BGI group was similar to that in the BGP 2.86 μm group. This result suggests that drinking Benifuuki green tea with a particle size of around 2 μm would deliver the anti-allergic EGCG3"Me and the anti-oxidant EGCG efficiently.
茶多酚，例如（-）-表没食子儿茶素-3-O-（3-O-甲基没食子酸酯（EGCG3“Me）、（-）-表没食子儿茶素-3-O-没食子酸酯（EGCG）、（-）-表没食子儿茶素（EGC）、（-）-表儿茶素-3-O-没食子酸酯（ECG）和（-）-表儿茶素（EC），被认为是茶有益作用的原因。“弁财天”，一种在日本种植的茶（Camellia sinensis L.），富含抗过敏分子表没食子儿茶素-3-O-（3-O-甲基）没食子酸酯（EGCG3“Me）。磨碎的弁财天绿茶粉（BGP）在日本的分布比叶茶更为广泛。日本人直接将他们的磨碎的茶与水混合，而饮用叶茶则是常见的做法。然而，对BGP 粒径对儿茶素生物利用度的影响进行的研究很少。本研究旨在研究大鼠灌胃弁财天绿茶后儿茶素的吸收情况。因此，我们评估了大鼠摄入不同平均粒径（2.86、18.6 和 76.1 μm）的弁财天绿茶粉（BGP）或弁财天绿茶浸提物（BGI）后儿茶素的血浆浓度。大鼠单次口服 125mg/大鼠剂量的弁财天绿茶后，分析了 EGCG3“Me、EGCG、ECG、EGC 和 EC 的生物利用度。使用库仑阵列电化学检测（ECD）的 HPLC 分析结合，测定了茶儿茶素的血浆浓度。（AUC）（药物浓度-时间曲线下的面积；min μg/mL）酯型儿茶素（EGCG3“Me、EGCG 和 ECG）对于 BGP 2.86 μm 明显高于浸提物和 18.6 和 76.1 μm BGP 组，但游离型儿茶素（EGC 和 EC）的 AUC 没有差异。关于 EGCG3“Me 的摄入调整后的血浆峰值水平，BGP 2.86 μm 和 BGI 高于 BGP 18.6 和 76.1 μm 组，其他儿茶素的血浆峰值水平也呈现相同趋势。本研究表明，通过减小绿茶的粒径，可以提高酯型儿茶素（EGCG 和 ECG）的生物利用度，但 BGI 组 EGCG3“Me 的血浆水平与 BGP 2.86 μm 组相似。这一结果表明，饮用粒径约为 2 μm 的弁财天绿茶可有效输送抗过敏的 EGCG3“Me 和抗氧化的 EGCG。
