Ginsenoside Rg3 induces ginsenoside Rb1-comparable cardioprotective effects independent of reducing blood pressure in spontaneously hypertensive rats

Ginsenoside Rg3 (Rg3) is a rare type of ginsenoside used as an anti-tumor medicine in China. Ginsenoside Rb1 (Rb1), which exhibits protective effects on the cardiovascular system, is similar to Rg3 in chemical structure. In the present study, Rb1 and Rg3 were administered for 6 weeks to spontaneously hypertensive rats (SHR) and their cardioprotective effects were assessed. According to echocardiography and histopathological examinations, the decrease in cardiac function and ventricular remodeling that occurred in SHR rats were attenuated by Rb1 and Rg3. However, tail-cuff blood pressure measurements indicated that Rb1 and Rg3 did not reduce blood pressure in SHR rats. The cardioprotective effects of Rb1 and Rg3 occurred independently of blood pressure reduction. Furthermore, immunohistochemistry (IHC) revealed that renin angiotensin system (RAS) activity in the myocardium of SHR was significantly attenuated by Rb1 and Rg3, whereas ELISA identified no significant changes of RAS activity in the serum. The results of IHC and reverse transcription-quantitative polymerase chain reaction demonstrated that levels of transforming growth factor β1, tumor necrosis factor-α, interleukin-6, interleukin-1 and endothelian-1 in the myocardium of SHR rats were reduced following Rb1 and Rg3 treatment. This may be due to the attenuation of RAS activity in the myocardium and the mechanisms of the cardioprotective effects of Rb1 and Rg3.