ABSTRACT
Aim To determine the plasma protein binding rate of five components of Eucommia ulmoides extract. Methods The equilibrium dialysis method was used to study the plasma protein binding rate. The plasma samples were extracted by protein precipitation with methanol. With the use of puerarin as the internal standard, UPLC-MS/MS was carried out to determine the concentration of the five compounds in and out of the dialysis membrane. Results The average plasma protein binding rates of five compounds on the area of the concentration which was determinate were as fol-lows, respectively: geniposidic acid was ( 25. 77 ± 2. 68 )%, protocatechuic acid was ( 57. 54 ± 3. 79)%, chlorogenic acid was (53. 91 ± 3. 00)%, pinoresinol diglucoside was (24. 15 ± 4. 92)%, and pinoresinol singleglucoside was (49. 78 ± 3. 61)%. Conclusions The results show that the binding percentage of geniposidic acid and pinoresinol diglucoside is relatively low, but the binding rate of the others with rat plasma protein is moderate.