FT-IR methodology for quality control of arabinogalactan protein (AGP) extracted from green tea (Camellia sinensis ).
FT-IR methodology for quality control of arabinogalactan protein (AGP) extracted from green tea (Camellia sinensis ).
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DOI：
10.1021/jf803707a
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发表时间：
2009-06
影响因子：
6.1
通讯作者：
Xiaoling Zhou;P. Sun;P. Bucheli;Tian-hua Huang;Dongfeng Wang
中科院分区：
文献类型：
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作者：
Xiaoling Zhou;P. Sun;P. Bucheli;Tian-hua Huang;Dongfeng Wang
针对从绿茶中提取和纯化的阿拉伯半乳聚糖蛋白（AGP）开发了一种快速质量控制方法。利用矢量角法和红外光谱分析，将二阶导数红外光谱中的1200-800 cm(-1)区域确定为绿茶AGP的关键指纹区域，其中1090-900 cm(-1)区域反映了绿茶AGP的保守性和共性特征。事实上，在二阶导数红外光谱中，关键单糖半乳糖 (Gal) 和阿拉伯糖 (Ara) 分别在约 1075 和 1045 cm(-1) 处有强峰，糖醛酸在约 1018 cm(-1) 处有强峰。可变区被确定位于约1134-1094和900-819 cm(-1)，可能是由于AGP之间的组成和结构差异所致。构建的方法对经过三种处理提取并纯化至表观均一性的绿茶 AGP 进行了测试，即水提取的茶树 AGP (CSW-AGP)、果胶酶提取的茶树 AGP (CSP-AGP) 和胰蛋白酶提取的茶树 AGP (CST-AGP)，Ara/Gal 比率为 1.37、1.57 和 1.82， 分别。在体外抗氧化活性方面，具有较高相似性（二阶导数红外光谱计算的cos theta值更接近）的AGP（CSW-AGP和CST-AGP）表现出相似的螯合亚铁离子能力和相似的清除羟基自由基的能力。总之，二阶导数红外光谱分析与矢量角法的结合成功地表征了绿茶 AGP，并被证明适用于其成分和活性辨别以及快速质量评估。
A rapid methodology of quality control was developed for arabinogalactan proteins (AGP) extracted and purified from green tea. Using the vectorial angle method and IR spectrum analysis, the 1200-800 cm(-1) region in second-derivative IR spectra was determined as the key fingerprinting region of green tea AGP, with the 1090-900 cm(-1) region reflecting their conservative and common characteristics. In fact, the key monosaccharides, galactose (Gal) and arabinose (Ara), were shown to have intense peaks at about 1075 and 1045 cm(-1), respectively, and uronic acids at about 1018 cm(-1) in second-derivative IR spectra. The variable region was identified to be at about 1134-1094 and 900-819 cm(-1) and was probably due to compositional and structural differences between AGPs. The constructed methodology was tested on green tea AGP extracted by three treatments and purified to apparent homogeneity as water-extracted Camellia sinensis AGP (CSW-AGP), pectinase-extracted C. sinensis AGP (CSP-AGP), and trypsin-extracted C. sinensis AGP (CST-AGP) with an Ara/Gal ratio of 1.37, 1.57, and 1.82, respectively. Regarding in vitro antioxidant activity, the AGPs (CSW-AGP and CST-AGP) with higher similarity (closer cos theta values calculated for second-derivative IR spectra) exhibited a similar ability of chelating ferrous ions and had a similar capability for scavenging hydroxyl radicals. In conclusion, the combination of second-derivative IR spectrum analysis and the vectorial angle method has allowed a successful characterization of green tea AGPs and was shown to be suitable for their compositional and activity discrimination and rapid quality evaluation.