Objective To investigate the effects and possible mechanism of the main component Ramulus Cinnamomi in the protective effect of Wuling Powder（五苓散） on renal injury in rats with adriamycin-induced nephropathy.Methods Doxorubicin hydrochloride（3 mg/kg） was injected twice into the tail vein to replicate the renal injury model of Sprague Dawley（SD） rats. A total of 60 successful modeling rats were randomly divided into model group

benazepril group

Wuling Powder group

Wuling Powder without Ramulus Cinnamomi group

and Wuling Powder without Ramulus Cinnamomi plus cinnamaldehyde group

with 12 in each group. Another 12 healthy SD rats were also selected as normal group. The benazepril group was given intragastric administration of benazepril hydrochloride tablet solution at a concentration of 1. 2 mg/ml. The Wuling Powder group was given intragastric administration of Wuling Powder solution at a concentration of 1. 6 mg/ml. The Wuling Powder group without Ramulus Cinnamomi was given intragastric administration of the Wuling Powder without Ramulus Cinnamomi solution at a concentration of 1. 4 mg/ml.The Wuling Powder without Ramulus Cinnamomiwas plus cinnamaldehyde given group was given intragastric administration of Wuling Powder without Ramulus Cinnamomiwas plus cinnamaldehyde given solution at a concentration of1. 403 mg/ml（final concentration of cinnamaldehyde was 3 mg/ml）. Each group was intragastrically administered at a dose of 10 ml/kg

and the normal and model groups were intragastrically administered with an equal volume of normal saline once a day for 28 days. After the last administration

the 24-hour urine volume of rats was recorded

and the urinary protein content

plasma creatinine

urea nitrogen

total cholesterol

triglyceride levels

and plasma malondialdehyde（MDA）

glutathione（GSH） content

and superoxide dismutase（SOD） activity were measured. HE（hematoxylin-eosin） staining of rat kidney tissue was performed for pathological observation. Results Compared with the normal group

the rats in the model group had decreased 24-hour urine volume

increased urinary protein content and plasma creatinine

triglyceride

total cholesterol

MDA

GSH content

and decreased SOD activity（P < 0. 05 or P <0. 01）. Glomerulosclerosis

degeneration and swelling of renal tubular epithelial cells

and interstitial fibrous tissue proliferation were observed pathologically. Compared with the model group

Wuling Powder group

Wuling Powder without Ramulus Cinnamomi group

and Wuling Powder without Ramulus Cinnamomi plus cinnamaldehyde group reduced the 24-hour urinary protein content

increased plasma SOD activity（P < 0. 05 or P < 0. 01）

and improved changes of renal pathology. Wuling Powder without Ramulus Cinnamomi plus cinnamaldehyde group also decreased plasma creatinine

MDA

GSH content

and increase 24-hour urine volume（P < 0. 05 or P < 0. 01）. The kidney pathological improvement was more obvious. Conclusion Cinnamaldehyde may be the main active component of Ramulus Cinnamomi

the key drug of Wuling Powder

and its mechanism on renal injury in rats with adriamycininduced nephropathy may be related to anti-oxidative stress.