重陽木的原花青素組成之鑑定

Identification of proanthocyanidin composition from Bischofia javanica Blume

許朔鳴(Shuo-Ming Hsu)

指導教授 ： 李綉鈴

大同大學/工程學院/生物工程學系所/碩士(2011年)

摘要

前人研究發現重陽木甲醇萃取物之水區分層含有豐富之原花青素含量及抗氧化性。本研究利用Sephadex LH-20管柱層析分離此水區分層，共獲得七個次區分，其中M1、M3及A3次區分之DPPH自由基清除力最佳，M1次區分之原花青素含量最高。硫解M1次區分再經由LC-MS/MS分離鑑定，並同時輔以半製備級HPLC收集，並以HRMS加以鑑定其單體組成。結果顯示M1次區分原花青素組成單元種類多，其頂端單體包含(+)catechin、(-)epicatechin gallate及(-)epigallocatechin gallate，而其延伸單體則包含gallocatechin、gallocatechin gallate、catechin及catechin gallate。進一步以HPLC-PDA檢測各次區分之硫解產物， 顯示除了M2次區分外，M3、A1、A2、A3及A4五個次區分均與M1次區分之頂端單體及 延伸單體組成相同。M3次區分之頂端單體以epigallocatechin gallate為主，其他次區分則以catechin為主；而六個次區分之延伸單體均以catechin為主要組成。皮爾森相關性分析顯示六個次區分之DPPH自由基清除力與沒食子酸莫耳比(G %)有高相關性，但與其平均聚合度(mDP)則無顯著相關。

關鍵字

原花青素 ； 抗氧化 ； 重陽木 ； 分子量鑑定 ； 解聚合

並列摘要

Aqueous fraction of methanolic extract from Bischofia javanica as reported to be rich in proanthocyanidin with high antioxidant activity. In this study, it was chromatographed on Sephadex LH-20 column into seven subfractions. M1、M3 and A3 subfractions exhibited strong DPPH radical scavenging activities, while M1 subfraction had the highest proanthocyanidin content. M1 subfraction was thiolyzed with toluene--thio, followed by LC-MS/MS, then the thiolyed productes was collected by semi-preparative HPLC, followed by HRMS resolution. Results showed that the polymeric proanthocyanidins were highly heterogeneous. (+)Catechin, (-)epicatechin gallate and (-)epigallocatechin gallate were the main terminal units, while catechin, gallocatechin, catechin gallate and gallocatechin gallate were as extension units. Through examining the thiolyzed products by HPLC-PDA, it was found that the terminal units and extension units of each subfraction, except M2, were identical to those of M1 subfraction. The main extension unit of each subfraction was catechin. Pearson correlation analysis suggested that the DPPH radical scavenging activity of subfractions was highly correlated with the molar percentage of galloylation (G %), but not (with) the mean degree of polymerization (mDP).

並列關鍵字

proanthocyanidin ； antioxidant ； Bischofia javanic

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