Studies on inclusion mechanism of 14-deoxyandrographolide-?-cyclodextrin / 中草药

ABSTRACT

Objective To study the inclusion mechanism of 14-deoxyandrographolide and ?-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;?G=-16.854 8;?H=-25.532;?S=-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.