Objective:To explore the impact and possible mechanism of praeruptorin C on cardiac hypertrophy in spontaneously hypertensive rats(SHR) and its possible mechanisms. Methods:Totally 20 SHR were randomly divided into the praeruptorin C group[praeruptorin C 20 mg/(kg·d)intragastric administrated,n=10]and the untreated control group(n = 10),with 10 age matched Sprague Dawley rats as normal group. The rats of each group were intervened for 8 weeks. We calculated the heart quality mass index (MHI) and left ventricular mass index(LVMI). We observed the morphological and structural changes of cardiomyocytes with optical microscope,and then the injuries of cell ultrastructure and mitochondria with transmission electron microscope. Then,we made homogenate and extracted RNA taken from heart tissue. The gene expression levels of phospholamban were determined by the method of semiquantitative RT-PCR. The phosphorylation of PLB was counted by liquid scintillation. Results:Compared with the SHR control group,the LVMI and HMI of SHR treated with praeruptorin C for 8 weeks were decreased(P < 0.05),the cardiac hypertrophy were reversed, the levels of PLB mRNA expression and the phosphorylation of PLB of the rats in the praeruptorin C group were increased (P < 0.05). Conclusion:Praeruptorin C had a certain effect on reversing the cardiac hypertrophy. The possible mechanisms might be upregulating the gene expression of sarcoplasmic reticulum phospholamban and increasing the phosphorylation level.