Hystological and pharmacological study of Thymus piperella (L.).

Histological and pharmacological assays have been carried out with methanol, hexane, dichloromethane and butanol extracts of Thymus piperella (L.) leaves. All the extracts were considered innocuo in the toxicity test. Methanol and also hexane, dichlorometane and butanol fractions, inhibited significantly the contractions induced by acetylcholine in isolated rat ileum in a concentration-dependent manner and the hexane extract was the most potent. However, the methanol extract did not modify the contractile effect of noradrenaline and histamine on isolated rat aorta and guinea-pig trachea respectively at the assayed dose (10, 100, 200 microg/mL). These results contribute to explain in part the use of this plant in folk medicine. In addition, morphological and histological structures characteristic of this species have been described for the first time.