In Vitro And In Vivo Anti-Leishmanial Effects Of Quercetin.pdf

# Investigation of In Vitro Anti-Leishmaniasis Effect of Quercetin

## Introduction
Leishmaniasis, a parasitic disease caused by protozoans from the Trypanosomatida family, presents in cutaneous, mucocutaneous, and visceral forms. Cutaneous leishmaniasis, particularly caused by Leishmania major, is prevalent in Iran and other endemic regions, with around 20,000 cases reported annually. Current treatments, based on antimony compounds, have drawbacks such as drug resistance and side effects. This study explores the potential of quercetin, a flavonoid compound found in various plants, as an alternative therapy.

## Materials and Methods
Leishmania major Culture: The standard L. major strain (MHOM/IR/75/ER) was cultured in NNN medium for five days, then transferred to RPMI-1640 medium for further proliferation.

Quercetin Preparation: Quercetin powder was dissolved in methanol to create various concentrations (1.61–50 μg/mL) in RPMI-1640 medium.

Promastigote Viability Assessment: L. major promastigotes were cultured in 96-well plates with different quercetin concentrations for 24 hours, followed by MTT assay to determine cell viability.

Amastigote Viability and EC50 Determination: Mouse macrophage cells (J774) were infected with L. major promastigotes to form amastigotes. Quercetin concentrations were added, and MTT assay was used to find the effective concentration (EC50) that reduced amastigote viability.

Animal Studies: Thirty Wistar rats were divided into five groups: one control group and four treatment groups receiving different quercetin concentrations (12.5, 25, 50 μg/mL). Rats were infected with L. major and monitored for lesion size every 5 days.

## Results
- In Vitro Studies: Quercetin significantly reduced L. major promastigote and amastigote viability in a dose-dependent manner, with EC50 values of 1.61 and 50 μg/mL, respectively.
- In Vivo Studies: Quercetin treatment led to a notable reduction in lesion size compared to the control group on day 30 (1.8 mm vs. 9.1 mm). No significant impact on mortality was observed after eight weeks of treatment.

## Conclusion
Quercetin exhibits potent in vitro and in vivo anti-leishmanial effects, suggesting its potential as a new therapeutic agent for cutaneous leishmaniasis. Further human trials are recommended to explore its clinical efficacy and safety.