Glycerol based carbon sulfonic acid catalyzed synthesis, in silico studies and in vitro biological evaluation of isonicotinohydrazide derivatives as potent antimicrobial and anti-tubercular agents

The present pathway involves synthesis of isonicotinohydrazide derivatives using isoniazid and diversely substituted aldehydes in the presence of EtOH and catalytic amount of glycerol based carbon sulfonic acid catalyst. The developed pathway has so many merits like excellent yields (91-98%), short reaction time (4-10 min), easy reaction set up, no need of column chromatography, large substrate scope, easily recyclable and reusable catalyst. The synthesized compounds were screened for antimicrobial and anti-tubercular activity and it was observed that compounds possessed high biological potency against the Gram positive and Gram negative bacterial and fungal strains. Regarding anti-tubercular activity, compound 3m exhibited high % inhibition against Mycobacterium tuberculosis H₃₇RV strain. Based on the outcome of in vitro studies, all the synthesized compounds were docked against E. coli (1KZN), C. albicans (1IYL), and M. tuberculosis H ₃₇ Rv strain (2NSD). The synthesized derivatives were docked within the binding site of 1KZN, and 1IYL. However, with 2NSD, apart from 3h, all the derivatives displayed interaction within the binding cavity of the protein. All the crucial interactions with Asn46, Asp73, and Arg136 in 1KZN, His227, Leu451 in 1IYL, and Tyr158 in 2NSD were witnessed in the top-scored docked candidates. Molecular docking studies revealed the importance of the substitution at R position on isonicotinohydrazide scaffold. The nitrogen atoms of hydrazide moiety were involved in forming hydrogen bonding with the active site amino acids, and the substitution at the R position occupy the hydrophobic position in the binding pocket. Also, the functional groups present on the substituted R position were involved in forming hydrogen bonding with the crucial active site residues.

One-step fabrication and characterization of Fe3O4/HBPE-DDSA/INH nanoparticles with controlled drug release for treatment of tuberculosis

In this study, Fe₃O₄/hyperbranched polyester-(2-dodecen-1-yl)succinic anhydride2-Dodecen-1-/isoniazid magnetic nanoparticles (Fe₃O₄/HBPE-DDSA/INH MNPs) with controlled drug release characteristics were synthesized successfully by a simple one-step method. Orthogonal experiments were performed to optimize the loading capacity and encapsulation efficiency of the MNPs. The structure of the Fe₃O₄/HBPE-DDSA/INH MNPs was characterized by ¹H nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization mass spectrometry, Fourier transform infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, and superconducting quantum interference device measurements, while their properties were characterized based on swelling behavior observations, in-vitro release experiments, and cytotoxicity analysis. The results indicated that the fabricated Fe₃O₄/HBPE-DDSA/INH MNPs had a high drug-loading capacity and encapsulation efficiency. Further, the drug-release rate of the MNPs was higher in an acidic buffer, indicating that the MNPs were pH-responsive. Swelling studies revealed that the MNPs exhibited diffusion-controlled drug release, while in-vitro release studies revealed that the drug-release properties could be controlled readily, owing to the high encapsulation efficiency of the MNPs and the uniform dispersion of the drug in them. These results collectively suggest that this multifunctional nontoxic drug delivery system, which exhibits good magnetic properties and pH-triggered drug-release characteristics, should be suitable for the treatment of tuberculosis.