Spasmolytic effect of Vitis vinifera hydroalcoholic leaf extract on the isolated rat uterus

Although leaf of Vitis vinifera (Vitaceae) has been used in traditional medicine to treat diarrhea, but no clinical and experimental studies have been conducted on its effects on the uterus. It has previously been reported that Vitis vinifera leaf extract reduces the ileum contractions induced by KCl and acetylcholine. The aim of the present study was to investigate the effect of Vitis vinifera hydroalcoholic leaf extract (VLHE) on the uterus of virgin rats. Extract was prepared by macerated method using 70% alcohol for 72 hours and the solvent was evaporated to obtain extract powder. Uterus of virgin rats was suspended in an organ bath containing De Jalon solution at 30 °C. Tissue contractility was isometrically recorded under 0.5 g initial tension. Potassium chloride (60 mM) and oxytocin (4 mU/mI) was applied to the tissue in the presence and absence of the extract (0.5, 1, 2, 4, and 8 mg/ml). The contractile force was calculated as percentage or as g/100 mg of tissue. KCl-induced contraction reduced by the extract in a dose-dependent manner (p<0.0001). Application of propranolol (1 µM) as a - adrenergic antagonist did not change KCI-induced contraction or extract-induced relaxation in the uterus. After application of oxytocin, extract at a concentration of 4 mg/ml was able to significantly reduce the oxytocin-induced contraction (p<0.0001). Application of the extract (4 mg/ml) 2 minutes before adding the stimulants KCl or oxytocin inhibited the tissue contractions. It seems that VHLE induces its inhibitory effects through the blockade of voltage- dependent calcium channels and adrenergic receptors are not involved in this inhibitory effect.