A series of 6 novel 2-amino-4, 5-diarylpyrimidines were synthesized by the reaction of isoflavones with guanidine. They were identified by the spectra of IR, 1H NMR, 13C NMR and elemental analysis. The protective effects of 2-amino-4, 5-diarylpyrimidines against oxygen-glucose deprivation leading by sodium hydrosulfite in PC12 cells were studied by MTT method. It was shown that 2-amino-4, 5-diarylpyrimidines exhibited neuroprotective effects against oxygen-glucose deprivation injury in PC12 cells, which could increase the amount of survival PC12 cells and reduce their injured degree in the model.

In order to guarantee the quality of traditional Chinese medicines (TCMs), the crystallization transformation of complex extracts of TCMs and the influence of solid form on their physicochemical properties were studied.The extract of total flavonoids from Pueraria lobata was taken as a model.Crystallization transformation happened when lofting under different conditions, and the intrinsic dissolution tests were carried out.It was found that humidity was the key factor to induce crystallization of total flavonoids from Pueraria lobata.The greater the wettability was, the more the crystallization was.The dissolution rate of total flavonoids from Pueraria lobata with the most crystallization amount significantly decreased by 96.51% compared to the sample without crystallization.After further simulating the preparation process of total flavonoids from Pueraria lobata, it was found that the wet granulation process with introduced water would also lead to crystallization and reduced dissolution rate.As for all crystallization samples, there was an inversely proportional relationship between the dissolution rates and the amount of crystallization.The risk of crystallization existed both in the storage and preparation process of TCM extracts.Crystallization would significantly affect the dissolution rate, and thus the quality of TCM products.In this study, the crystallization transformation of amorphous complex TCM extracts was discovered, and the effect of the crystallization transformation on its dissolution behavior was systematically studied, which provides a new research idea for assuring the quality of TCM products and promoting the improvement of TCM preparation level.