Pyrazolo[3,4-d]pyrimidine analogues: synthesis, characterization and their in vitro antiamoebic activity

Targeting the cysteine biosynthesis pathway in microorganisms: Mechanism, structure, and drug discovery

Owing to the global health crisis of resistant pathogenic infections, researchers are emphasizing the importance of novel prevention and control strategies. Existing antimicrobial drugs predominantly target a few pathways, and their widespread use has pervasively increased drug resistance. Therefore, it is imperative to develop new antimicrobial drugs with novel targets and chemical structures. The de novo cysteine biosynthesis pathway, one of the microbial metabolic pathways, plays a crucial role in pathogenicity and drug resistance. This pathway notably differs from that in humans, thereby representing an unexplored target for developing antimicrobial drugs. Herein, we have presented an overview of cysteine biosynthesis pathways and their roles in the pathogenicity of various microorganisms. Additionally, we have investigated the structure and function of enzymes involved in these pathways as well as have discussed drug design strategies and structure-activity relationships of the enzyme inhibitors. This review provides valuable insights for developing novel antimicrobials and offers new avenues to combat drug resistance.

Speculative analysis on the electronic structure, IR assignments and molecular docking of N-{4-[(4-amino-3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)sulfonyl]phenyl}acetamide, an anti-amoebic agent

An exhaustive quantum mechanical calculations on a pharmaceutically critical molecule N-{4-[(4-amino-3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)sulfonyl]phenyl}acetamide have been investigated through the B3LYP/6-31G∗∗ Density Functional and HF/6-31G∗∗ Wave Function techniques. Physicochemical parameters along with the advanced electronic structure parameters like; MEP (molecular electrostatic potentials) and highest occupied & lowest unoccupied molecular orbitals (HOMO-LUMO) analysis have additionally been scanned over both methods. The computed HOMO-LUMO energy demonstrates that charge exchange takes place inside the molecule. The estimated small HOMO-LUMO energy gap, through both methods, indicates that the molecule is chemically reactive. Further, the IR vibrational spectra of the molecule have been assigned in the region 400-4000 cm⁻¹ through the DFT technique. The anticipated vibrational assignments have been compared with the experimental values accounted for in the literature. To comprehend the mode of binding, docking investigations of the molecule alongwith the co-crystallized metronidazole (MNZ) molecule were accomplished with O-acetyl-serine-sulfhydrylase (OASS) enzyme using GLIDE-SP and GLIDE-XP modules. Docking simulations and reported biological activities (IC50) demonstrate that the title molecule may act as a lead molecule for constraining the progression of Entamoeba histolytica illness.

New antiprotozoal agents: Synthesis and biological evaluation of different 4-(7-chloroquinolin-4-yl) piperazin-1-yl)pyrrolidin-2-yl)methanone derivatives

In an endeavor to develop efficacious antiprotozoal agents 4-(7-chloroquinolin-4-yl) piperazin-1-yl)pyrrolidin-2-yl)methanone derivatives (5-14) were synthesized, characterized and biologically evaluated for antiprotozoal activity. The compounds were screened in vitro against the HM1: IMSS strain of Entamoeba histolytica and NF54 chloroquine-sensitive strain of Plasmodium falciparum. Among the synthesized compounds six exhibited promising antiamoebic activity with IC₅₀ values (0.14-1.26μM) lower than the standard drug metronidazole (IC₅₀ 1.80μM). All nine compounds exhibited antimalarial activity (IC₅₀ range: 1.42-19.62μM), while maintaining a favorable safety profile to host red blood cells. All the compounds were less effective as an antimalarial and more toxic (IC₅₀ range: 14.67-81.24μM) than quinine (IC₅₀: 275.6±16.46μM) against the human kidney epithelial cells. None of the compounds exhibited any inhibitory effect on the viability of Anopheles arabiensis mosquito larvae.

Progress of the synthesis of condensed pyrazole derivatives (from 2010 to mid-2013)

Condensed pyrazole derivatives are important heterocyclic compounds due to their excellent biological activities and have been widely applied in pharmaceutical and agromedical fields. In recent years, numerous condensed pyrazole derivatives have been synthesized and advanced to clinic studies with various biological activities. In this review, we summarized the reported synthesis methods of condensed pyrazole derivatives from 2010 until now. All compounds are divided into three parts according to the rings connected to pyrazole-ring, i.e. [5, 5], [5,F 6], and [5, 7]-condensed pyrazole derivatives. The biological activities and applications in pharmaceutical fields are briefly introduced to offer an orientation for the design and synthesis of condensed pyrazole derivatives with good biological activities.