Spasmolytic Effects of Hydroalcoholic Extract of Melissa Officinalis on Isolated Rat Ileum

Lemon balm (Melissa officinalis) has spasmolytic activity and is used in gastrointestinal complains in traditional medicine. In this study, the effect and potency of different concentrations of hydroalchoholic extract of the plant were evaluated on isolated rat ileum. The extract of the leaves of lemon balm was prepared by maceration method and different concentrations of the extract were tested on isolated N.Mari rat ileum in an organ bath containing tyrode solution. To evaluate the potency, the relaxing effect of the extract was compared with the corresponding values for atropine and verapamil (10^-6 and 10^-7 M, respectively). The findings showed that the extract is able to inhibit contraction induced by carbachol (6.8×10^-7 M) and KCl (20 M) at concentrations of 4 and 5.6 mg/ml, respectively, and leads to the relaxation of the smooth muscle of the intestine. It was also observed that 4 mg/ml concentration of the extract can exert an inhibitory effect similar to that of 10-7 M verapamil. The results show that the antispasmodic effect of Melissa officinalis' hydroalcoholic extract is associated with the involvement of muscarinic receptor and calcium channels and that the plant can be proposed as therapeutic agent for gastrointestinal spasms due to its potency.