Objective To investigate the effects of different processed products of Dahuang（ Radix et Rhizoma Rhei） on human renal cortex proximal tubule epithelial cells（ HK-2 cells） and to screen the best decoction time.Methods Decoction pieces of raw Radix et Rhizoma Rhei

prepared Radix et Rhizoma Rhei

wine processed Radix et Rhizoma Rhei

and charred Radix et Rhizoma Rhei were collected 350 g each and divided into 7 equal parts. Each medicine was respetively decocting for 5

7

9

10

15

20

30 minutes

and finally a concentration of about 1000 g/L was prepared. Totally 145 rats were randomly divided into a raw Radix et Rhizoma Rhei group

a prepared Radix et Rhizoma Rhei group

a wine processed Radix et Rhizoma Rhei group

and a charred Radix et Rhizoma Rhei group

and each group was further divided into subgroups at decocting time 5

7

9

10

15

20

and 30 minutes

with 5 rats in each subgroup. Additional 5 rats were set as control group. Rats in each drug group were given the corresponding Radix et Rhizoma Rhei decoction by gavage at a dose of 1. 35 g/（ kg·d）

while the control group was given 0. 9%Sodium chloride twice a day

and drug-containing serum was prepared after gavage on the 6 th day. The drug containing serum with different decocting time and different processed products of Radix et Rhizoma Rhei was used to interfere with the induction of HK-2 cells by transforming growth factor β1（ TGF-β1） for 24 hours. The epithelia-cadherin（ E-cadherin） and alpha smooth muscle actin（ α-SMA） concentration in HK-2 cells of each group were measured.Results The lowest α-SMA concentrations were in the raw Radix et Rhizoma Rhei 10 min subgroup（ 52. 086 ng/ml）

the prepared Radix et Rhizoma Rhei 10 min subgroup（ 44. 596 ng/ml）

the wine processed Radix et Rhizoma Rhei 9 min subgroup（ 49. 768 ng/ml）

and the charred Radix et Rhizoma Rhei 9 min subgroup（ 58. 470 ng/ml）. The highest concentrations of E-cadherin were the raw Radix et Rhizoma Rhei 10 min subgroup（ 1. 017 ng/ml）

the prepared Radix et Rhizoma Rhei 10 min subgroup（ 1. 325 ng/ml）

the wine processed Radix et Rhizoma Rhei 9 min subgroup（ 1. 163 ng/ml）

and the charred Radix et Rhizoma Rhei 9 min subgroup（ 0. 787 ng/ml）. Compared with the charred Radix et Rhizoma Rhei group

the concentration of α-SMA decreased and the concentration of E-cadherin increased in the other 3 groups（ P < 0. 05 or P < 0. 01）. Compared with the prepared Radix et Rhizoma Rhei group

theα-SMA concentration increased and the E-cadherin concentration decreased in the raw Radix et Rhizoma Rhei group and the wine processed Radix et Rhizoma Rhei group（ P < 0. 05 or P < 0. 01）. The differences between α-SMA and E-cadherin concentrations in the wine processed Radix et Rhizoma Rhei group and the raw Radix et Rhizoma Rhei group were also statistically significant（ P < 0. 05）. Conclusion The 4 processed products of Radix et Rhizoma Rhei can effectively inhibit the transformation of epithelial mesenchyme of HK-2 cells induced by TGF-β1

and their effects are in order from strong to weak: prepared Radix et Rhizoma Rhei

wine processed Radix et Rhizoma Rhei

raw Radix et Rhizoma Rhei

and charred Radix et Rhizoma Rhei. The best decocting time for raw Radix et Rhizoma Rhei and prepared Radix et Rhizoma Rhei is 10 min

and 9 min for wine processed Radix et Rhizoma Rhei and charred Radix et Rhizoma Rhei.