Tang Tie-xin, Guo Wei-yan, Xu Ye, Zhang Si-ming, Xu Xin-jun, Wang Dong-mei, Zhao Zhi-min, Zhu Long-ping, Yang De-po
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China, 510006.
Phytochem Anal. 2014 May-Jun;25(3):266-72. doi: 10.1002/pca.2502. Epub 2014 Feb 4.
Poplar tree gum has a similar chemical composition and appearance to Chinese propolis (bee glue) and has been widely used as a counterfeit propolis because Chinese propolis is typically the poplar-type propolis, the chemical composition of which is determined mainly by the resin of poplar trees. The discrimination of Chinese propolis from poplar tree gum is a challenging task.
To develop a rapid thin-layer chromatographic (TLC) identification method using chemometric fingerprinting to discriminate Chinese propolis from poplar tree gum.
A new TLC method using a combination of ammonia and hydrogen peroxide vapours as the visualisation reagent was developed to characterise the chemical profile of Chinese propolis. Three separate people performed TLC on eight Chinese propolis samples and three poplar tree gum samples of varying origins. Five chemometric methods, including similarity analysis, hierarchical clustering, k-means clustering, neural network and support vector machine, were compared for use in classifying the samples based on their densitograms obtained from the TLC chromatograms via image analysis.
Hierarchical clustering, neural network and support vector machine analyses achieved a correct classification rate of 100% in classifying the samples. A strategy for TLC identification of Chinese propolis using chemometric fingerprinting was proposed and it provided accurate sample classification.
The study has shown that the TLC identification method using chemometric fingerprinting is a rapid, low-cost method for the discrimination of Chinese propolis from poplar tree gum and may be used for the quality control of Chinese propolis.
杨树胶的化学成分和外观与中国蜂胶（蜂蜡）相似，由于中国蜂胶通常是杨树型蜂胶，其化学成分主要由杨树树脂决定，因此杨树胶被广泛用作假冒蜂胶。区分中国蜂胶和杨树胶是一项具有挑战性的任务。
开发一种快速的薄层色谱（TLC）鉴定方法，利用化学计量指纹图谱区分中国蜂胶和杨树胶。
开发了一种新的TLC方法，使用氨和过氧化氢蒸汽的组合作为可视化试剂来表征中国蜂胶的化学特征。三名独立的人员对八个不同来源的中国蜂胶样品和三个杨树胶样品进行了TLC分析。比较了五种化学计量方法，包括相似度分析、层次聚类、k均值聚类、神经网络和支持向量机，用于根据通过图像分析从TLC色谱图获得的密度图对样品进行分类。
层次聚类、神经网络和支持向量机分析在对样品进行分类时的正确分类率达到了100%。提出了一种利用化学计量指纹图谱进行中国蜂胶TLC鉴定的策略，该策略提供了准确的样品分类。
该研究表明，利用化学计量指纹图谱的TLC鉴定方法是一种快速、低成本的区分中国蜂胶和杨树胶的方法，可用于中国蜂胶的质量控制。
