RESUMO
The widespread use of medicinal herbs among the general population gives rise to the possibility of therapeutic or toxic effects in patients that use these plants. The effects of Thymus vulgaris [TV] hydroalcoholic extract on the contractile responses of the isolated guinea-pig ileum were investigated. Male guinea pigs that were starved for 24 hours were decapitated after cervical dislocation, and terminal ileum were removed. Segments were fixed at a resting tension of 0.5 g in an organ bath containing in Tyrode solution at 37°C, which was bubbled with 95% oxygen and 5% carbon dioxide. The effects of the Thymus vulgaris extracts at six concentrations ranging from 0.02 to 6 mg/ml. Each segment served as its own control. Paired Student's t-test was used for statistical analysis. p < 0.05 was considered to be significant. Thymus vulgaris inhibited the contractile response in a dose-dependent manner in 0.6mg/mI concentration decreased the amplitude of the muscles up to 60% [t = -5.67, P<0.02]. This inhibitory activity was blocked by Granisetron and inhibited the contractions induced by acetylcholine, the activities of this plant may be due to the anticolinergic effect and block of serotoninergic pathways. Regression analysis had shown that with increasing in extract concentration the effect of extract was increased [r = 0.96, p<0.001]. The coefficient of extract dose was 0.089 mg. Our results demonstrate that extract prepared from the plant of Thymus vulgaris inhibited electrical induced contractions of the guinea-pig ileum when tested in vitro. This effect is dose dependent and reversible