目的从包合比例、主客体分子间相互作用、包合部位和包合稳定性方面研究阐明14-去氧穿心莲内酯和β-环糊精形成包合物的机制。方法采用差示热分析法确证包合物的形成,紫外法测定包合常数并计算热力学常数,IR、1H-NMR确证包合部位。结果包合常数(Ka)值为1 292.631 L/mol;包合过程ΔG=-16.854 8;ΔH=-25.532;ΔS=-0.029 12。由IR和1H-NMR可以看出包合物中14-去氧穿心莲内酯五元内酯环及十氢萘环部分发生了变化。结论形成包合物的主客体比例为1∶1,范德华力在包合过程中起主要作用,包合部位为十氢萘环及五元内酯环,形成的包合物常温下比较稳定。

Objective To study the inclusion mechanism of 14-deoxyandrographolide and β-cyclodextrin in inclusion ratio,molecular interaction between host and guest,inclusion part and stability of inclusion compound.Methods The formation of inclusion compound was confirmed by dfferential thermal analysis(DTA);The equilibrium constants of inclusion compound were determined and the thermodynamic constants were calculated by UV;Inclusion parts were confirmed by IR and 1H-NMR.Results Ka=1 292.631 L/mol;ΔG=-16.854 8;ΔH=-25.532;ΔS=-0.029 12.It was clearly that all five lactone ring and decalin ring of 14-deoxyandrographolide in indusion compound changed in IR and 1H-NMR.Conclusion inclusion host-guest ratio is 1∶1,Van der Waals forces play a major role in the process.Inclusion site is decalin ring and five lactone ring.The inclusion compound is more stable under normal temperature.