Agricultural and Biological Research

Investigation of in vitro anti-leishmaniasis effect of quercetin

Reza Ranjbar, Peyman Shayanfar, Mahmood Maniati, Faham Khamesipour

The five-capacity antimony compounds, as the current treatment for cutaneous leishmaniasis, have disadvantages such as drug resistance and risk of relapse. Therefore, we studied the effect of quercetin on the growth of Leishmania major promastigotes and amastigotes as a new therapeutic approach. The effect of various concentrations of quercetin on Leishmania major promastigotes and amastigotes viability was evaluated after 24 hours of treatment. The percentage of parasite viability was determined by MTT colorimetric method. Thirty Wistar male rats were divided into 5 groups (n=6) including A1, A2, A3 and control which received 12.5, 25, 50 and 0 µg/ml of quercetin respectively after being infected by leishmaniasis through IP injection(Figure 2). The fifth group was SHAM which did not receive any compounds and were studied only for the confirmation of optimized housing conditions of rats. All rats were followed up every 5 days by measurement of lesion size and counting existing amastigotes in sample via Giemsa staining during the treatment period.  After 24 hours of parasite culture, the promastigotes and amastigotes populations decreased in the presence of various concentrations of Quercetin, and at 1.61 and 50 μg/mL concentrations, the lethality rate was 21.65% and 73.29%, respectively. Data displayed that this compound efficiently relieved the lesions on the 30th day of treatment (1.8 compared to 9.1mm in control) and reduced amastigotes population present in samples. Also, the mortality rate was not affected by Quercetin in rats 8 weeks after treatment.  Our data indicated that Quercetin has in-vivo and in-vitro anti-leishmanial effects, triggering ideas to replace ordinance therapies with such new treatment which leads to patient improvements and reduced the side-effects. Therefore, further studies on quercetin in human subjects are recommended.