CONTEXT:

Different Hypericum species such as Hypericum perforatum (HP) L. and Hypericum triquetrifolium Turra are well known and widely used traditional medicine in Turkey.

OBJECTIVES:

We investigated the effect of standardized HP extract on endothelium and vascular function.

MATERIALS AND METHODS:

After suspending the aortas with endothelium in organ baths containing Krebs solution, contractile and relaxant responses were assessed in the absence and presence of HP (0.05 mg/ml).

RESULTS:

Although there were significant reductions in the contractile responses to phenylephrine (1113.73 ± 164.11; 477.40 ± 39.94; p < 0.05) and potassium chloride (745.58 ± 66.73; 112.58 ± 26.58; p < 0.05), no differences in the relaxant responses to acetylcholine (94.61 ± 2.65; 87.79 ± 9.40) and sodium nitroprusside (108.82 ± 5.06; 106.43 ± 7.45) were observed.

DISCUSSION AND CONCLUSION:

These data suggest that even the high dose of HP intervention does not bring any harmful effect on endothelium and smooth muscle function; meanwhile it might be beneficial on some of diseases accompanied with increased vascular contraction.