Background: Due to the harmful side effects of chemical drugs, in recent decades, much attention has been returned to the use of medicinal plants. The flavonoids as plant secondary compounds are allocated to own an important part of this attention. Based on previous studies, some of the flavonoids are able to reduce contraction induced by KCl, acetylcholine, etc in rat ileum. Therefore, in this study, the effect of the flavonoid extract of parsley leaves on smooth muscle contraction of the ileum and the role of Nitric oxide (NO) has been studied.

  Materials and Methods: Distal segment of Wistar rat ileum was separated and contractions under one gram tension and at 37°C, in an organ bath containing Tyrode solution was recorded by isotonic method. Rats were divided into 2 groups with 7 in each group. After placing the tissue exposed to L-NAME 100&muM (Sigma, America) as an inhibitor of NO, the antispasmodic effect of cumulative concentrations of the flavonoid extract was investigated

  Results: The extract cumulative concentrations reduced ileum contraction induced by KCl in a dose-dependent manner. Also, the antispasmoide effect of flavonoids extract on ileum contractions (only 16 mg/ml) was affected by L-NAME.

Conclusion: This study showed that the extract relaxed rat's ileum by the NO system at higher concentrations.