Document Type : Original paper
Department of Pharmacognosy, School of Pharmacy, Lorestan University of Medical Sciences, Khorramabad, Iran.
Department of Microbiology, College of Medicine, University of Thiqar, Thiqar, Iraq.
Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran.
Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran.
Background and objectives: Chemical drugs such as metronidazole, quinacrine and furazolidone are used to treat giardiasis. Although these drugs are useful in most cases, they are associated with some side effects. The present investigation was designed to evaluate the antiparasitic effects and cellular mechanisms of Astragalus maximus chloroformic extract against both trophozoites and cysts of Giardia. Methods: The extraction was done based on the maceration method with 70% methanol. The in vitro anti-Giardia effects of various concentrations of A. maximus extract (11.25, 22.5, and 450 mg/mL) were evaluated on cysts and trophozoites of G. lamblia for 15-360 min. In addition, the effects on the plasma membrane permeability and the induction of apoptosis in the trophozoites of G. lamblia were studied. Results: Astragalus maximus extract significantly (p<0.0001) declined the viability of cysts of G. lamblia; in both concentrations of 22.5 mg/mL and 45 mg/mL, the extract killed 100% of G. lamblia cysts after 240 and 360 min of incubation. The results also showed that the extract in both concentrations of 22.5 mg/mL and 45 mg/mL, killed 100% of G. lamblia trophozoites after 120 and 240 min incubation The findings revealed that treatment of G. lamblia trophozoites with A. maximus extract increased the permeability of the plasma membrane in a dose dependent response. The extract, especially at the concentration of 10 mg/mL, significantly (p<0.001) induced caspase-3 activation. Conclusion: The present study showed the promising in vitro antiparasitic effects of A. maximus extract against both trophozoites and cysts of G. lamblia by affecting the permeability of the plasma membrane and induction of apoptosis. Further investigations especially in animal models and clinical setting are required to clarify the accurate efficacy and mechanisms against G. lamblia infection.