我国西南元江大理茶的挥发性成分及其抗氧化活性

大理茶(Camellia taliensis)为山茶科山茶属茶组植物,主要分布于云南横断山脉澜沧江至伊洛瓦底江流域,即从云南的西部及西南部至缅甸北部.在其分布区,大理茶亦被称为野生大茶树,常用于加工制作茶叶.采用水蒸气蒸馏法、GC及GC/MS联用技术,首次对大理茶的鲜幼叶和鲜幼叶及老叶分别制成的绿茶中的挥发性成分进行提取和分析,共鉴定出91个化合物.研究结果表明,大理茶鲜幼叶的主要香气成分为棕榈酸(30.52％),亚油酸(19.82％),植醇(8.75％)和亚麻酸乙酯(2.54％)等有机酸及其酯和二萜类,而制成绿茶后,其主要香气成分则为芳樟醇(28.43％),脱氢芳樟醇(1.13％),α-松油醇(11.68％),橙花醇(4.92％)和香叶醇(12.34％)等单萜醇类成分.从大理茶鲜叶到由其制成的绿茶,香气成分发生了较大变化,形成了28种原鲜叶中未检测到的香气成分,其中,(Z,Z,Z)-9,12,15-十八烷三烯-1-醇的含量分别达到1.21％(幼叶绿茶)和11.2％(老叶绿茶),是大理茶制作的绿茶的特征香气成分.DPPH和ABTS+自由基清除实验结果显示大理茶鲜叶及其制成的绿茶的挥发性成分均具有一定的抗氧化活性,但均弱于茶多酚的抗氧化活性.

Chemical Compositions and Antioxidant Activity of Essential Oil from Green Tea Produced from Camellia taliensis （Theaceae） in Yuanjiang, Southwestern China

Camellia taliensis belonging to Camellia sect. Thea （Theaceae） is distributed from the western and south- western areas of Yunnan Province, China to the north of Myanmar. Known as the ＂wild＂ tea plant, it has been com- monly used for making tea by the local people of its growing area. It is the first investigation of the volatile constituents of the fresh tender leaves of C. taliensis and green teas produced from its tender and older leaves. The volatile constituents were obtained by hydrodistillation and analyzed by GC and GC-MS. Ninety-one compounds were identified. The results showed that the main compositions of volatile oil of the fresh tender leaves were hexadecanoic acid （30.52%）, linoleic acid （ 19.82% ）, phytol （8.75%）, and geraniol （2.54%）, while monoterpenoids （58.51% ） composing of linalool （28.43%）, hotrienol （ 1.13% ）, a-terpineol （ 11.68% ）, nerol （4.92%） and geraniol （ 12.34% ） were the major volatile components of its green tea product. From the fresh leaves to the green tea products, 28 aro- ma components were formed. Among then, the content of （Z, Z, Z）-9, 12, 15-octadecatrien-l-ol （peak 77） was up to 1.21% （from tender leaves） and 11.2% （from older leaves）, respectively. The DPPH and ABTS radical scavenging assays demonstrated a moderate activity of essential oil from the three essential oils of C. taliensis.