Antispasmodic activity of apigenin and luteolin, two components of Dracocephalum kotschyi extract, on rat ileum contractions

Introduction: Aerial parts of Dracocephalum kotschyi have been used as antispasmodic agents in Iranian traditional medicine. Recent pharmacological studies confirmed antispasmodic activity of D. kotschyi extract. The objective of this research was to investigate antispasmodic activities of apigenin and luteolin to find out if they are responsible for the spasmolytic activity of hydroalcoholic extract of D. kotschyi. Methods: Aerial parts of D. kotschyi were extracted with ethanol. Antispasmodic effect of hydroalcoholic extract of D. kotschyi, apigenin and luteolin were examined on KCl and/or acetylcholine (ACh)-induced contractions in rat isolated ileum. Results: Hydroalcoholic extract of D. kotschyi concentrations-dependently inhibited KCl and ACh induced contractions with IC۵۰ values of ۴۱ ± ۱۰ μg/mL and ۱۳۳ ± ۱۹ μg/mL, respectively. Apigenin concentrations-dependently inhibited KCl and ACh induced contractions with IC۵۰ values of ۵۷ ± ۱۲ μM and ۸۰ ± ۱۸ μM, respectively. Luteolin concentrations-dependently inhibited KCl induced contractions with IC۵۰ values of ۶۸ ± ۱۴ μM. Loperamide reduced both KCl and ACh induced contraction with IC۵۰ values of ۱۸۹ ± ۴۴ nM and ۸۲ ± ۲۰ μM, respectively. Conclusion: In this study apigenin and luteolin were identified as two active ingredients responsible for antispasmodic activities of D. kotschyi extract.