RESUMO
Objective: To study the effects of association complexes on extraction and separation behavior of mangiferin in Pingfei Decoction by low-field and high-field NMR. Methods Using the T2 relaxation time and chemical shifts value of hydrogen as index, and group DNJ-citric acid as control, the relaxation characteristrics of hydrogen in association state was analyzed by low field NMR to verify the structure of association complexes combined with high-field NMR. Results DNJ and mangiferin existed in the form of association state with larger molecular weight, which inhibited the migration of components from medicinal materials to solution and caused lower transmittance. And the T2 peak shifted to the left in the spectrum, and the chemical shift in the high field nuclear magnetic field also changed. Conclusion This experiment clarified the mechanism of the effect of presence of components on extraction and separation behavior of mangiferin and provided technical support for studying the decocting method and mechanism of Chinese herbal compound.