Amaç: Mevcut in-silico araştırması, Leishmania infantum lipofosfoglikan (LPG) ve γ-glutamilsistein sentetazına (γ-GCS) karşı umut verici ilaçlar bulmak amacıyla 20000 Gıda ve İlaç İdaresi onaylı ilaç bileşiklerinin taranması için tasarlandı ve uygulandı. Yöntemler: Her iki hedefin protein sekansı alındıktan sonra, 3D yapıları tahmin edildi ve doğrulandı. Moleküler yerleştirme iki varsayılan hedef (LPG ve γ-GCS) arasında yapıldı ve ligand-reseptör etkileşimlerini tahmin etmek için AutoDock 4.2 programı kullanılarak onaylanmış bileşikler seçildi. Bulgular: Yirmi bin ilaç bileşiği üzerinde deney yapıldıktan sonra, γ-GCS reseptörü için iki ve LPG reseptörü için beş olmak üzere toplam yedi ligand, bağlanma afiniteleri ve enerjilerine göre yeni, güçlü anti-leishmanial ilaçlar olarak belirlenmiştir. Bunlardan 5 ligand 8,5 kcal/mol'e kadar daha negatif Δ Gbinding ile LPG reseptörüne iyi bağlanma kapasitesi gösteren sitotoksik ve anti-kanser özelliklere sahipti. Bunlardan 2 ligand, 7,8 kcal/mol'e kadar daha negatif Δ Gbinding ile glutamil reseptörüne iyi bir bağlanma kapasitesi gösterdi. Sonuç: En yeni yazılım tabanlı yöntemler, yeni ilaç keşfi için organizmalarda biyolojik hedeflere özgü yeni peptid şablonlarını taramak ve tahmin etmek için güçlü araçlardır. Bununla birlikte, in vitro ve in vivo tekniklerin kullanımı, öngörülen ligandların öz Objective: Current in-silico research was designed and administered for the screening of 20000 Food and Drug Administrationapproved drug compounds with the goal of finding promising drugs against lipophosphoglycan (LPG) and γ-glutamylcysteine synthetase (γ-GCS) of Leishmania infantum. Methods: After the protein sequence of both targets was taken, the 3D structures of protein of interest were predicted and validated. Molecular docking was done among the two putative targets (LPG and γ-GCS) and approved compounds were selected using AutoDock 4.2 program to predict ligand-receptor interactions. Results: After docking experiment was done on 20000 drug compounds, a total number of seven ligands, two for γ-GCS receptor and five for LPG receptor, were assigned as novel, potent anti-leishmanial drugs based on their binding affinity and energy. Of those, five ligands possessed cytotoxic and anti-cancer characteristics and showed good binding capacity to LPG receptor with Δ Gbinding up to 8.5 kcal/mol more negative; while two compounds showed good binding capacity to glutamyl receptor with Δ Gbinding up to 7.8 kcal/mol more negative. Conclusion: The latest software-based methods are powerful tools for scanning and predicting new peptide templates specific to biological targets in organisms for new drug discovery. However, the use of in vitro and in vivo techniques is a requirement for better evaluation of the potential of projected ligands with the help of in-silico approaches, identifying molecular mechanism of action of the more active compounds is possible. This can help in defining the most likely molecular target, so that the subsequent optimization using in vitro and in vivo techniques ...

Background: In the era of drug resistant organisms, there exists a huge need to overcome this issue. Drug repositioning is the action of repurposing current drugs against alternative targets. Objectives: Herein, we assessed the antileishmanial activity of ethinyl estradiol and tolmetin on the promastigotes and amastigotes of Leishmania infantum, using methyl thiazolyl tetrazolium (MTT) and atomic force microscopy (AFM) methods. Methods: Following previous in silico evaluation of 3358 FDA-approved compounds, ethinyl estradiol and tolmetin drugs were selected. Promastigote assay was done in RPMI 1640 culture in 96-well plates (10 5 /100 µL). Also, axenic amastigotes cultured in acidic RPMI 1640 were seeded in 96-well plates (5 × 10 4 parasites). Raw 264.7 macrophages were seeded at a density of 3 × 10 6 cells/well. Then, the macrophages were infected with metacyclic promastigotes of L. infantum. Also, drug solvent and amphotericin B were considered as control wells. Drug challenge was performed in triplicate with different concentrations of ethinyl estradiol (250, 125, 62.5, 31.25, 15.62 and 7.81 µg/mL) and tolmetin (200, 100, 50, 25, 12.5 and 6.25 µg/mL) and cell viability was assessed by MTT assay. AFM imaging was done to observe morphological changes. Results: The main finding of our investigation was the substantial effect of ethinyl estradiol on promastigotes, and amastigotes of L. infantum during 24, 48 and 72 h, according to MTT results and cellular morphology observations. Thus, the IC50 of this drug on promastigote, axenic amastigotes and macrophage-dwelling amastigotes during 72 h was 23, 45 and 32 µg/mL, respectively. However, tolmetin was not effective against L. infantum parasites. Cellular alteration, was observed by AFM technique. Conclusions: This study showed that ethinyl estradiol had good anti-leishmanial activity and it is recommended to test this drug under in vivo condition. With the aid of drug repurposing we could substitute the old drugs with novel compounds for a specific disease.