Antiparasitic Effect of Leaf Extract and Major Metabolites of Pelargonium quercetorum Agnew. against Leishmania Major: In Vitro and In Silico Studies

Document Type : Original Article


1 Department of Parasitology and Mycology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran

2 Nanobiotechnology Department, Faculty of Innovative Science and Technology, Razi University, Kermanshah, Iran

3 Department of Biological Sciences, Faculty of Science, University of Kurdistan, Sanandaj, Iran


Introduction: Leishmania is flagellate protozoa, the cause of leishmaniasis that has affected more than 12 million people in 88 countries throughout the world. The aim of this study was to evaluate the cytotoxic effect of the aqueous leaf extract and the main metabolites of Pelargonium quercetorum plant species on amastigotes and promastigotes forms of Leishmania major via in vitro and in silico surveys.
Materials and Methods: The cytotoxicity on the promastigotes and amastigotes was calculated by direct counting and MTT assay for 24, 48, and 72 h in different concentrations of the plant extract. In silico study, the interactions of four major metabolites of P. quercetorum including α-Pinene, α-Fenchyl acetate, limonene, and trans-β-Caryophyllene were evaluated towards the major virulence factor of L. major (GP63). After three days, samples exposed to 1, 5, and 10 mg/ml of plant extract showed a significant reduction compared to the control group.
Results: IC50 values of P. quercetorum extract and amphotericin B were 1508.99 and 86.34 µg/ml, respectively, following 24 h of incubation. Surprisingly, in vitro results indicated that the P. quercetorum extract had a cytotoxic effect on amastigotes and promastigotes of L. major by non-dose-dependent effect.
Conclusions: Molecular docking illustrated that the highest binding affinity (˗6.1 kcal/mol) was found for trans-β Caryophyllene as bicyclic sesquiterpene. Docking studies showed a more efficient interaction of trans-β-Caryophyllene with GP63 compared to other metabolites.