Purpose:The imidazopyridine moiety is important pharmacophore that has proven to be useful for a number of biologically relevant targets, also reported to display antibacterial, antifungal, antiviral properties. Riboflavin biosynthesis involving catalytic step of Lumazine synthase is absent in animals and human, but present in microorganism, one of marked advantage of this study. Still, this path is not exploited as antiinfective target. Here, we proposed different interactions between [1H,3H] imidazo[4,5-b] pyridine test ligands and target protein Lumazine synthase (protein Data Bank 2C92), one-step synthesis of title compounds and further evaluation of them for in vitro antimicrobial activity.Materials and Methods:Active pocket of the target protein involved in the interaction with the test ligands molecules was found using Biopredicta tools in VLifeMDS 4.3 Suite. In-silico docking suggests H-bonding, hydrophobic interaction, charge interaction, aromatic interaction, and Vanderwaal forces responsible for stabilizing enzyme-inhibitor complex. Disc diffusion assay method was used for in vitro antimicrobial screening.Results and Discussion:Investigation of possible interaction between test ligands and target lumazine synthase of Mycobacterium tuberculosis suggested 1i and 2f as best fit candidates showing hydrogen bonding, hydrophobic, aromatic and Vanderwaal's forces. Among all derivatives 1g, 1j, 1k, 1l, 2a, 2c, 2d, 2e, 2h, and 2j exhibited potent activities against bacteria and fungi compared to the standard Ciprofloxacin and Fluconazole, respectively. The superiority of 1H imidazo [4,5-b] pyridine compounds having R’ = Cl >No2 > NH2 at the phenyl/aliphatic moiety resident on the imidazopyridine, whereas leading 3H imidazo[4,5-b] pyridine compounds containing R/Ar = Cl > No2 > NH2> OCH3 substituents on the 2nd position of imidazole.

The proteasome was first identified as a high MW protease complex that gets resolved into a series of low MW protein species upon denaturation. As the dominant protease dedicated to protein turnover, the proteasome shapes the cellular protein repertoire. Our knowledge of proteasome regulation and activity has improved considerably over the past decade. Novel inhibitors, in particular, have helped to advance our understanding of proteasome biology. They range from small peptide-based structures that can be modified to vary target specificity to large macromolecular inhibitors that include proteins. Although these reagents have an important role in establishing our current knowledge of the proteasome's catalytic mechanism, many questions remain. The future lies in designing compounds that can function as drugs to target processes involved in disease progression. Our focus in this chapter is to highlight the use of various classes of inhibitors to probe the mechanism of the proteasome and to identify its physiological significance in the cell, so that the mechanism of inhibition of proteasome will work as a definite source for design of protocols for newer therapeutic agents for the treatment of inflammation and in cancer therapy.

Simvastatin has low aqueous solubility resulting in low oral bioavailability (5%) and thus presents a challenge in formulating a suitable dosage form. To improve the aqueous solubility, a solid dispersion formulation of Simvastatin was prepared by lyophilization utilizing skimmed milk as a carrier. Six different formulations were prepared with varying ratios of drug and carrier and the corresponding physical mixtures were also prepared. The improvement of amorphous state through solid dispersion was confirmed by differential scanning calorimetry and X-ray diffraction studies. The optimum drug-to-carrier ratio of 1:9 enhanced solubility nearly 30-fold as compared to pure drug. In-vitro drug release studies exhibited a cumulative release of 86.69% as compared to 25.19% for the pure drug. Additionally, scanning electron microscopy studies suggested the conversion of crystalline Simvastatin to an amorphous form. In a Triton-induced hyperlipidemia model, a 3-fold increase in the lipid lowering potential was obtained with the reformulated drug as compared to pure drug. These results suggest that solid dispersion of Simvastatin using skimmed milk as carrier is a promising approach for oral delivery of Simvastatin.

RP-HPLC method have been Development and Validation For Simultaneous Estimation for Metformin And Sitagliptin in Bulk and Tablet Formulation was developed using Grace C18 column(250nm x 4.6ID, Particle size: 5 Micron) as stationary phase and methanol : HPLC grade water (80:20%v/v, pH3.0) as mobile phase was maintained at a flow rate of 0.8ml/min, the retention time of Metformin And Sitagliptin were found to be 6.19 min and 7.42 min and detection was carried out at 254nm. The high recovery and low coefficients of variation confirm the suitability of the method for simultaneous analysis of the Sitagliptin and Metformin in bulk and tablet Formulation. The validated method was successfully used for quantitative analysis of Janumet tablet.

In the present study, the isolation, purification and partial characterization of thermostable serine alkaline protease produced from Bacillus thuringinsis SH-II-1A was reported. The culture was isolated from soil of slaughter house waste and identified further from ribosomal sequence. The crude enzyme was purified by ammonium sulfate precipitation, dialysis and Sephadex G-200 gel permeation chromatography up to 17.04 fold with recovery of 8.47%. Relative molecular weight (67 kDa) of purified enzyme was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Maximum production of enzyme and cell biomass was observed for 48 h of incubation period at 45°C. Strong activity of enzyme was observed at pH 10 to 11; also stability of up to 2 and 20 h incubation at the same pH range confirms alkaline protease. Optimum temperature recorded for protease activity was 45°C, and 100% thermal stability up to 350 min of incubation was recorded. Among different natural substrates tried, casein was found as ideal substrate. Enzyme activity was strongly enhanced by metal ions like Ca 2+ , Mg 2+ and Mn 2+ whereas, 100% enzyme activity was inhibited by phenylmethylsulphonyl fluoride (PMSF), and up to 92% inhibition by diisopropyl fluorophosphates (DFP) confirmed serine protease. Detergent compatibility of the enzyme was studied in the presence of 10 mM CaCl 2 and 1 M glycine at 45°C. This indicates 80 to 100% stability for a period of 0.5 to 2.5 h incubation. Improved washing performance and removal of blood stains from the cotton cloth was observed when detergent Surf excel was used with enzyme. Overall, the observed properties of isolated protease conclude its commercial application in detergent and leather industries.

Background: Dihydrofolate reductase is one of the important enzymes for thymidylate and purine synthesis in micro-organisms. A large number of drugs have been designed to inhibit microbial DHFR but over the period of time, some drugs have developed resistance and cross reactivity towards the enzyme. Over the past few decades, benzimidazoles, triazoles and their derivatives have been grabbing the attention of the synthetic chemists for their wide gamut of antibacterial and antifungal activities targeting microbial protein DHFR. Objective: Our goal behind present investigation is to explore benzimidazoles class of drugs as microbial DHFR inhibitors by studying ligand-receptor binding interactions, in vitro enzyme inhibition assay and confirmation of anti-microbial activity against selected pathogenic microorganisms. Methods: A library containing thirty novel 2,6-disubstituted 1H-benzimidazoles was synthesized by one pot condensation of o-nitro aniline or 2,4-dinitro aniline with series of aldehydes or acetophenones using Na2S2O4 or SnCl2 respectively and reflux for 5-6hr. Structures of compounds have been confirmed by spectroscopic methods as 1H and 13C NMR, FT-IR and MS. In vitro DHFR inhibition study was performed by using Epoch microplate reader and IC50 of the test compounds was compared with Trimethoprim. In vitro antimicrobial activity was performed against selected clinical pathogens by agar disk diffusion method and MIC (µg/mL) was reported. Results: Moderate to good level of DHFR inhibition was observed with IC50 values in the range of 7-23 µM. Compounds B1, B19, B22, B24 and B30 expressed 1.1 to 1.4 folds more prominent DHFR inhibitory activity as compared to standard Trimethoprim. Remarkable antimicrobial activity was exhibited by B1, B19, B22, B24 and B30. Molecular docking study revealed perfect binding of test ligands with key amino acids of DHFR as Phe31, Ile94, Ile5, Asp27, Gln32 and Phe36. Conclusion: Nature of 1H-benzimidazole substituents at position 2 and 6 had influence over magnitude and type of molecular binding and variation in the biological activity. The present series of 1H-benzimidazoles could be considered promising broad-spectrum antimicrobial candidates that deserve in future for preclinical antimicrobial evaluation and development of newer antimicrobial agents targeting microbial DHFR.