依次和多次连续TLC研究桂枝主成分制备色谱分离

Study on preparative chromatographic separation of chemical components from cassia twig by sequentially and repeatedly continuous TLC

目的:研究桂枝主成分制备色谱分离。方法:以桂枝正己烷萃取物为研究对象,在HPLC/MS鉴定其组成基础上,采用依次和多次连续薄层色谱(TLC)研究了TLC保留行为和色谱可分性,预测了柱色谱台阶梯度分离结果;同时对其进行了系统分离。结果:桂枝正己烷萃取物含有香豆素、肉桂酸、桂皮醛、邻甲氧基桂皮醛等12个化合物;正己烷/乙酸乙酯展开体系极性依次增大的TLC表明,各化合物的容量因子与二元展开体系中强极性溶剂的体积分数存在lnk=a+bln C+c C的函数关系;在同一展开体系TLC多次展开时,化合物比移值变化呈线性关系,不同溶剂强度下同一化合物的斜率不同。结论:依次TLC预测桂枝主成分制备色谱分离准确有效,多次TLC使分离对象RF介于0.20-0.35间,ΔRF>0.06时可实现制备色谱分离。

Objective： To study the preparative chromatographic separation of chemical components from cassia twig. Methods： Preparative chromatography separation methods for chemical compounds from n-hexane extract of cassia twig were studied by sequentially and repeatedly continuous TLC. The retention behaviors and chromatographic separability of main compounds from cassia twig were explored on the basis of its composition in HPLC/MS identification. The results of stepwise gradient elution column chromatography was predicted by TLC. The system separation was carded out at the same time. Results： There were 12 compounds in n-hexane extract of, cassia twig, which included coumarin, cinnamic acid, cinnamic aldehyde, o-methoxy cinnamic aldehyde and so on. The TLC results which developed with n-hexane and ethyl acetate solvent system showed that function between capacity factor of compounds and volume fraction of polar solvent in binary solvents was lnk=a＋blnC＋cC. The linear relationship was found for RF values of compounds in continuous development TLC at one single proportion, and the slopes of this linear were different in different solvent strength. Conclusion： Stepwise gradient elution preparative column chromatography of chemical compounds from cassia twig is accurate and effective by TLC. Good separation would be obtained in column chromatography when △RF value of adjacent material is more than 0.06 and RF value ranges from 0.20 to 0.35, then achieves preparative chromatographic separation.