Thiadiazine thione derivatives as anti-leishmanial agents: synthesis, biological evaluation, structure activity relationship, ADMET, molecular docking and molecular dynamics simulation studies

During last decades, 3,5-disubstituted-tetrahydro-2H-thiadiazine-2-thione scaffold remains the center of interest due to their ease of preparation, diverse range substituents at N-3 and N-5 positions, and profound biological activities. In the current study, a series of 3,5-disubstituted-tetrahydro-2H-thiadiazine-2-thiones were synthesized in good to excellent yield, and the structure of the compounds were confirmed by various spectroscopic techniques such as FTIR, 1H-NMR, 13C-NMR and Mass spectrometry, and finally evaluated against Leishmania major. Whereas, all the evaluated compounds (1-33), demonstrate potential leishmanicidal activities with IC50 values in the range of (1.30- 149.98 uM). Among the evaluated compounds such as 3, 4, 6, and 10 exhibited excellent leishmanicidal activities with IC50 values of (2.17 μM), (2.39 μM), (2.00 μM), and (1.39 μM), respectively even better than the standard amphotericin B (IC50 = 0.50) and pentamidine (IC50 = 7.52). In order to investigate binding interaction of the most active compounds, molecular docking study was conducted with Leishmania major. Further molecular dynamic simulation study was also carried out to assess the stability and correct binding of the most active compound 10, within active site of the Leishamania major. Likewise, the physiochemical properties, drug likeness, and ADMET of the most active compounds were investigated, it was found that none of the compounds violate Lipiniski's rule of five, which show that this class of compounds had enough potential to be used as drug candidate in near future.Communicated by Ramaswamy H. Sarma.

Serological Cross-Reaction between Six Thiadiazine by Indirect ELISA Test and Their Antimicrobial Activity

Malaria is a parasitic infection caused by a protozoon of the genus Plasmodium, transmitted to humans by female biting mosquitoes of the genus Anopheles. Chloroquine and its derivates have caused the parasite to develop drug resistance in endemic areas. For this reason, new anti-malarial drugs as treatments are crucial. This work aimed to evaluate the humoral response. with hyper-immune sera, of mice immunized with six derivatives of tetrahydro-(2H)-1,3,5-thiadiazine-2-thione (bis-THTT) by indirect ELISA test. The cross-reactivity between the compounds as antigens and their microbial activity on Gram-positive and Gram-negative bacteria was evaluated. The results of the humoral evaluation by indirect ELISA show that three bis-THTTs react with almost all of the above. Besides, three compounds used as antigens stimulate the BALB/c mice’s immune system. The best combination of two antigens as a combined therapy displays similar absorbances between the antigens in the mixture, showing similar recognition by antibodies and their compounds. In addition, our results showed that different bis-THTT presented antimicrobial activity on Gram-positive bacteria, mainly on Staphylococcus aureus strains, and no inhibitory activity was observed on the Gram-negative bacteria tested.

Design, synthesis and in vitro antikinetoplastid evaluation of N-acylated putrescine, spermidine and spermine derivatives

A structure-activity relationship study on polyamine derivatives led to the synthesis and the determination of antikinetoplastid activity of 17 compounds. Among them, a spermidine derivative (compound 13) was specifically active in vitro against Leishmania donovani axenic amastigotes (IC50 at 5.4μM; Selectivity Index >18.5) and a spermine derivative (compound 28) specifically active against Trypanosoma brucei gambiense (IC50 at 1.9μM; Selectivity Index >52).

Thiadiazines, N,N-heterocycles of biological relevance

The 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione scaffold has found many applications in recent years. This review is aimed at highlighting the most important aspects of these compounds: Synthesis, spectroscopic characterization and biological activities. How the chemical nature of N-substituents influences the overall activity and cytotoxicity profile will also be discussed.

Thiadiazine derivatives as antiprotozoal new drugs

The 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione scaffold have found many applications in recent years. This review is aimed at highlighting the most important aspects about these compounds: synthesis, spectroscopic characterization and antiprotozoan activities. How the chemical nature of N-substituents influences the overall activity / cytotoxicity profile will also be discussed.