Eungwanichayapant P D, Popluechai S
School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand.
Plant Physiol Biochem. 2009 Feb;47(2):94-7. doi: 10.1016/j.plaphy.2008.11.002. Epub 2008 Nov 17.
Catechins are a group of polyphenols found in tea (Camellia sinensis var. sinensis) at high levels. They are beneficial for health. From the study on accumulation of catechins in shoots and mature leaves of a tea cultivar, Oolong No. 17, using high-performance liquid chromatography (HPLC), it was found that the amounts of most catechins in the shoots were higher than those in the mature leaves, with an exception of catechins gallate (CG) that was found in trace amounts in both the shoots and mature leaves. mRNA accumulation of genes involved in catechin synthesis was studied using reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the mRNA accumulation of the genes were higher in the shoots than in the mature leaves. These genes included genes of phenylalanine ammonia-lyase 1 (PAL1; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), dihydroflavonol 4-reductase (DFR; EC 1.1.1.219), leucoanthocyanidin reductase (LCR; EC 1.17.1.3), and flavanone 3-hydroxylase (F3H; EC 1.14.11.9).
儿茶素是一类在茶叶（中华变种茶树）中大量存在的多酚类物质。它们对健康有益。通过使用高效液相色谱法（HPLC）对茶树品种乌龙17号的新梢和成熟叶片中儿茶素的积累情况进行研究发现，新梢中大多数儿茶素的含量高于成熟叶片，不过没食子儿茶素（CG）在新梢和成熟叶片中均含量甚微。使用逆转录聚合酶链反应（RT-PCR）研究了参与儿茶素合成的基因的mRNA积累情况。结果表明，这些基因在新梢中的mRNA积累量高于成熟叶片。这些基因包括苯丙氨酸解氨酶1（PAL1；EC 4.3.1.5）、查尔酮合酶（CHS；EC 2.3.1.74）、二氢黄酮醇4-还原酶（DFR；EC 1.1.1.219）、无色花青素还原酶（LCR；EC 1.17.1.3）和黄烷酮3-羟化酶（F3H；EC 1.14.11.9）的基因。
