Synthesis and characterization of polyaniline-drug conjugates as effective antituberculosis agents

Exploring the Staphylococcus aureus Gyrase Complex and Human Topoisomerase: Potential Target for Molecular Docking and Biological Studies with Substituted Polychloroaniline

This paper targets the nuclease activity of polymeric chemical compounds toward bacterial genomic DNA and also elucidates their probable drug-like properties against the enzymes bacterial gyrase complex and human topoisomerase. Poly-o-chloroaniline, poly-m-chloroaniline, and poly-o,m-chloroaniline were synthesized by a chemical oxidation method. The structure of the polymers was characterized by the powder X-ray diffraction pattern, which suggested the ordered structure of the polymer, where the parallel and perpendicular periodicities of the polymeric chain were arranged systematically. The molecular transition of polymers was determined by a UV-visible spectrum study. A polymeric arrangement of the molecule can be seen in scanning electron microscopy (SEM) images. Among the three polymers chosen for the biological study and molecular docking studies, poly-m-chloroaniline showed more affinity to bind against both the selected targets (HT IIIb TB and SAGS) in comparison to the ortho- and ortho-meta substituents of polyaniline. The biophysical interaction analysis is in line with molecular docking, which shows that poly-m-chloroaniline forms many different categories of interactions and binds very strongly with the selected targets. The synthesized and tested molecules have potential nuclease activity, which is well aligned with molecular docking studies against the bacterial gyrase complex and human topoisomerase.

Synthesis and characterization of PANI and PANI-indole copolymer and study of their antimalarial and antituberculosis activity

The preparation of polyaniline (PANI) and its copolymer with indole involved a chemical oxidative polymerization method, with benzene sulfonic acid (BSA, C6H6O3S) used as a dopant and potassium persulfate (PPS, K2S2O8) as an oxidant. The synthesized compounds underwent characterization using FTIR, 1H-NMR, TGA, and GPC techniques, which allowed the calculation of their average molecular weight and polydispersity index (PDI) through the GPC technique. The PDI values of the PANI copolymer with indole in different aniline-to-indole ratios were 1.53, 1.13, and 1.532 for 1:1, 1:2, and 2:1 ratios, respectively. Thermal stability was determined using TGA, revealing that the indole heterocyclic compound increased the inflexibility of the polymer chains in the synthesized PANI copolymer. The structure of the copolymer was further analyzed using 1HNMR and FTIR techniques, which confirmed the existence of benzenoid and quinoid groups in the PANI-indole copolymers, as well as the effect of doping on the polymer chains. The antibacterial and antifungal properties of the copolymers were studied against several bacterial and fungal strains and measured in terms of minimum inhibitory concentration. Results indicated that the inhibition rate of the PANI-indole copolymer on S. pyogenus (MTCC 442) was higher than that of standard drugs and individual PANI. The PANI-indole copolymers also displayed excellent antituberculosis and antimalarial activities, with the synthesized copolymer showing better outcomes than individual PANI.