Navin Kumar Mogha

Metal complex of the first-generation quinolone antimicrobial drug nalidixic acid: structure and its biological evaluation.

A novel binuclear squire planar complex of nalidixic acid with Ag(I) metal ion with the formula [Ag(Nal)2] has been synthesized. The synthesized metal complex was characterized using CHN analysis, Fourier-transformed infra-red (FT-IR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), ultra violet–visible (Uv–vis) and single-crystal X-ray diffraction (XRD). The newly synthesized complex shows more advanced antifungal activity compared to the parent quinolone against four fungi, namely Pythium aphanidermatum, Sclerotinia rolfsii, Rhizoctonia solani and Rhizoctonia bataticola.

Effect of Imidazolium-Based Ionic Liquids on the Structure and Stability of Stem Bromelain: Concentration and Alkyl Chain Length Effect

In the present work, changes in the structure and stability of stem bromelain (BM) are observed in the presence of a set of four imidazolium-based ionic liquids (ILs) such as 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-hexyl-3-methylimidazolium chloride ([Hmim][Cl]), and 1-decyl-3-methylimidazolium chloride ([Dmim][Cl]), using various biophysical techniques. Fluorescence spectroscopy is used to observe the changes taking place in the microenvironment around the tryptophan (Trp) residues of BM and its thermal stability because of its interactions with the ILs at different concentrations. Near-UV circular dichroism results showed that the native structure of BM remained preserved only at lower concentrations of ILs. In agreement with these results, dynamic light scattering revealed the formation of large aggregates of BM at higher concentrations of ILs, indicating the unfolding of BM. In addition to this, the results also show that higher alkyl chain length imidazolium-based ILs have a more denaturing effect on the BM structure as compared to the lower alkyl chain length ILs because of the increased hydrophobic interaction between the ILs and the BM structure. Interestingly, it is noted that low concentrations (0.01-0.10 M) of short alkyl chain ILs only alter the structural arrangement of the protein without any significant effect on its stability. However, high concentrations of all five ILs are found to disrupt the structural stability of BM.