ABSTRACT
Aim To evaluate the inhibitive and induc-tive effects of Polygonum capitatum water extract on main cytochrome P450 isoforms in human and liver mi-crosomes of mouse in vitro for predicting the herb-drug interactions in clinical application. Methods The in vitro inhibitory effect was evaluated by incubating Po-lygonum capitatum water extract with the probe sub-strates of main phase I metabolic enzymes in human liver microsomes, including CYP1A2, CYP2E1, CYP2C9,CYP2C19 and CYP3A4. Mice were adminis-tered with Polygonum capitatum water extract at dosage of 0 . 58 g · kg-1 and 1 . 16 g · kg-1 by gastric lavage for successive 7 days and 14 days, then the cocktail-LC-MS/MS method was applied to assess the inductive effect of main CYP450 isoforms in mouse liver micro-somes. Results The IC50 values of Polygonum capita-tum water extract on main CYP450 isoforms in human liver microsomes were from 849 . 6 mg · L-1 to 2 287 mg·L-1 . Compared with the blank control group, the activites of CYP2C9 and CYP3A4 in 1. 16 g·kg-1 7 d group were about 49 . 9 % and 21. 1 % higher ( P <0. 01, P < 0. 05 ) respectively, the activities of CYP2C9 and CYP3A4 in 0. 58 g·kg-1 7 d group were 27. 6 % and 15. 5 % higher ( P <0. 01 , P <0. 05 ) respectively, the activities of CYP2C9 and CYP3A4 in 1. 16 g·kg-1 14 d group were 67. 5 % and 32. 1 %higher (P<0. 01) respectively, while the activities of CYP1 A2 , CYP2 E1 and CYP2 C19 were not increased significantly in Polygonum capitatum treatment group. Conclusions Polygonum capitatum water extract do not show the inhibitory effect on main CYP450 in hu-man liver microsomes. There is induction on CYP2C9 and CYP3 A4 in mouse liver microsomes by Polygonum capitatum water extract.
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.