Natural Sciences and Science Education Academic Group, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore.
Talanta. 2011 Jan 15;83(3):891-8. doi: 10.1016/j.talanta.2010.10.048. Epub 2010 Nov 4.
Uncaria sinensis (Oliv.) Havil (Rubiaceae) has been used as an important Traditional Chinese Medicine (TCM) herb for the treatment of fevers and various nervous disorders. The major bioactive secondary metabolites from different classes of chemical compounds, i.e. organic acid, flavonoid and alkaloid, present in this TCM herb, namely catechin, caffeic acid, epicatechin and rhynchophylline, were extracted by microwave-assisted extraction (MAE) method with ultra-pure water as the extraction solvent. The optimal extraction conditions for this green solvent MAE method were found to be 100°C for 20 min. The recoveries of the compounds were found to be comparable to that of heating under reflux using ultra-pure water for 60 min. The method precision (RSD, n=6) was found to vary from 0.19% to 5.60% for the proposed method on different days for the secondary metabolites. Simultaneously, the key primary metabolites such as sucrose and phenylalanine for the biosynthesis of bioactive secondary metabolites were successfully characterized by GC-MS. Furthermore, an approach using the combination of primary and secondary metabolite profiling based on their chemical fingerprints with Principal Component Analysis (PCA) was successfully developed to evaluate the quality of U. sinensis obtained from different sources. This approach was shown to be feasible in discriminating U. sinensis from different origins and thus a potential application for the quality control of other medicinal herbs.
钩藤（Uncaria sinensis (Oliv.) Havil）（茜草科）作为一种重要的中药，用于治疗发热和各种神经紊乱。该中药中的主要生物活性次生代谢产物来自不同类别的化学化合物，即儿茶素、咖啡酸、表儿茶素和钩藤碱，采用微波辅助提取（MAE）法，以超纯水作为提取溶剂进行提取。发现该绿色溶剂 MAE 方法的最佳提取条件为 100°C 20 分钟。发现化合物的回收率与使用超纯水回流加热 60 分钟相当。对于不同天的次生代谢物，该方法的精密度（RSD，n=6）在 0.19%至 5.60%之间变化。同时，利用 GC-MS 成功地对生物活性次生代谢物生物合成的关键初级代谢物如蔗糖和苯丙氨酸进行了表征。此外，还成功地开发了一种基于其化学指纹图谱的主成分分析（PCA）的组合使用初级和次级代谢产物分析的方法，用于评估来自不同来源的钩藤的质量。该方法被证明可用于区分不同来源的钩藤，因此可用于其他草药的质量控制。
