Effect of Vitis Vinifera Leaf Extract on Ileum Mechanical Activity in Rat

Vitis vinifera (grape) is from Vitaceae family and many researches have performed on its seed but not on leaf. It has been reported that Vitis vinifera leaf extract induces relaxation in rat uterus, aorta, trachea and vas deferens precontracted by KCl. According to these reports, the inhibitory effects have been evoked through the voltage dependent calcium channels blockade. The aim of present study was to investigate the effect of Vitis vinifera leaf hydroalcoholic extract (VHLE) on rat ileum contractions induced by KCl, acetylcholine (ACh) and barium chloride.

Vitis vinifera leaf powder was extracted using manerated method by 70% alcohol for 72 h at ambient temperature and then solvent was evaporated. From Sprague Dawley rats (male and female) pieces of ileum (2cm) were isolated and placed in an organ bath (10ml) containing Tyrode’s solution gassed with oxygen. An isotonic transducer recorded contractions under 0.5g initial tension. The mean±SEM of changes in length (mm) or the percentages of length changes were calculated.

The results indicate that VHLE (0.25, 0.5, 1, 2 and 4mg/ml) reduces the ileum contractions induced by KCl (60mM) dose dependently (P<0.001). This inhibitory effect was unaffected by propranolol (1μM). VHLE (1mg/ml) also inhibited the ileum contractions induced by ACh (0.05 and 0.5μg/ml) P<0.001 and P<0.05 respectively. Ileum contraction induced by BaCl2 (4mM) was unaffected by VHLE (2mg/ml).

In conclusion, it seems that VHLE inhibits ileum contractions via blocking the voltage dependent calcium channels. Ineffectiveness of propranolol on inhibitory effect of extract indicates that the adrenoceptors are not involved in this inhibitory effect. VHLE failed to relax ileum precontracted by BaCl2 probably because, BaCl2 increases intracellular calcium concentration via releasing calcium ions from intracellular pools that was not affected by VHLE.