ABSTRACT
Examination of chemical compositions of essential oil distilled from the fruit of Zanthoxylum limonella Alston (Rutaceae) revealed the presence of 33 chemical components. Evaluation of the oil composition was achieved by GC/MS analysis. Limonene (31.09%), terpin-4-ol (13.94%) and sabinene (9.13%) were found to be the major components. Effects of essential oil have been performed in isolated guinea pig ileum, rat thoracic aorta and conscious mice. The essential oil at the concentration of 7.68 x 10(-5)-1.92 x 10(-3) microl/25 ml, produced dose-dependent contraction of the isolated rat thoracic aorta. These contractions were significantly reduced by pretreatment with prazosin (1 x 10(-7) M) and verapamil (1 x 10(-7) M). Its contraction was abolished in calcium free Krebs solution. Contractile response to the volatile oil (2 x 10(-6)-5.12 x 10(-4) microl/25 ml) was examined in isolated guinea pig ileum, it evoked ileal contraction in concentration-dependent manner and the contractions were suppressed after exposure to chlorpheniramine (1 x 10(-7) M) cypoheptadine (1 x 10(-7) M) atropine (1 x 10(-7) M) and verapamil (1 x 10(-7) M). Therefore, it could be concluded that the essential oil from the fruit of Zanthoxylum limonella possessed stimulation effect on different smooth muscle preparations by non-specific mechanisms. It involved the non receptor and receptor-mediated mechanism. Gastrointestinal stimulant effect of the essential oil was confirmed in intact mice since the oil significantly increased black ink movement from the stomach to ileo-caecal junction after oral feeding.