The inhibition of KCl (60 mM)-pre-contracted rat thoracic aorta ring with endothelium denuded (−E) and with intact endothelium (+E) in response to cumulative addition of SFI, HSI and FPI.

Each dose of SFI can significantly inhibit KCl-induced contraction of aorta rings with intact endothelium, while had no significant effect on the contraction of aorta rings with denuded endothelium (A); 2 ml/L and 10 ml/L of HSI had a similar role as SFI (B); FPI had no significant effect on KCl-induced contraction of thoracic aorta ring with denuded and intact endothelium (C). **P<0.01 vs Control (the control group was added an equal volume K-H solution).