Background: The anti-inflammatory effects of Cynodon dactylon have been determined in some previous studies. Nevertheless, there is no comprehensive study about immunomodulatory effects of C. dactylon. The present study was performed to investigate the modulatory effects of C. dactylonon macrophages functions of NMRI mice.

Methods: This survey was an experimental intervention study. The  study  population  consisted  of  14  male  NMRI  mice  randomly  categorized  into  3 treatment groups and one control group (each group was contained 10 mice). Mice in treatment groups received hydroalcoholic extract of C. dactylon for 3 constitutive weeksin different doses (100,200 and 400 mg/Kg- every day, orally). Control mice received PBS at the same volume. At the end of study, macrophages isolated from peritoneal cavity of mice and the neutral red uptake, respiratory burst after challenge with tetra phorbol acetate and respiratory burst after challenge with opsonized yeast were evaluated in these population. Data were analyzed using the one-way ANOVA plus Turkey’s test. P values of less than 0.05 were considered statistically significant.

Results: The results of stimulation of macrophages with ester of phorbol showed a significant increase in respiratory burst of macrophages isolated from treatment groups compared to control mice (p<0.01). Nevertheless, when macrophages challenged with opsonized yeast, there was no significant difference between groups .Moreover, the results of neutral red uptake by macrophages didn’t show any significant difference between macrophages of control and treatment groups.

Conclusion: However, the hydroalcoholic extract of C. dactylon caused a significant decrease in the production of the potentially harmful free radical, but it could not interfere with the function of macrophages after challenge with a real infection.