P. Muralidhar Reddy

Antimicrobial study of newly synthesized 6-substituted indolo[1,2-c]quinazolines

A new series of indolo[1,2-c]quinazoline derivatives were prepared in good yield through reaction of 2-(o-aminophenyl)indole with a variety of arylaldehydes. The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR and mass spectral studies and elemental analysis. All the title compounds were investigated for their activity against certain strains of Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Streptococcus pyogenes), Gram-negative bacteria (Salmonella typhimurium, Escherichia coli and Klebsiella pneumonia) and pathogenic Fungi (Aspergillus niger, Candida albicans and Trichoderma viridae). Ampicillin and ketoconazole were used as reference compounds. The results revealed that some of synthesized compounds displayed marked activity against all the tested microorganisms.

Identification of Pathogens by Mass Spectrometry

Abstract Background: Mass spectrometry (MS) is a suitable technology for microorganism identification and characterization. Content: This review summarizes the MS-based methods currently used for the analyses of pathogens. Direct analysis of whole pathogenic microbial cells using MS without sample fractionation reveals specific biomarkers for taxonomy and provides rapid and high-throughput capabilities. MS coupled with various chromatography- and affinity-based techniques simplifies the complexity of the signals of the microbial biomarkers and provides more accurate results. Affinity-based methods, including those employing nanotechnology, can be used to concentrate traces of target microorganisms from sample solutions and, thereby, improve detection limits. Approaches combining amplification of nucleic acid targets from pathogens with MS-based detection are alternatives to biomarker analyses. Many data analysis methods, including multivariate analysis and bioinformatics approaches, have been developed for microbial identification. The review concludes with some current clinical applications of MS in the identification and typing of infectious microorganisms, as well as some perspectives. Summary: Advances in instrumentation (separation and mass analysis), ionization techniques, and biological methodologies will all enhance the capabilities of MS for the analysis of pathogens.

6-substituted indolo[1,2-c]quinazolines as new antimicrobial agents.

A series of 2‐o‐arylidineaminophenylindoles and their cyclic derivatives (indolo[1,2‐c]quinazolines) were synthesized. The reactions occurred under relatively mild conditions and afforded the desired product in good yields. Molecular structures of the synthesized compounds were confirmed by IR, 1H‐NMR, 13C‐NMR, MS spectra, and elemental analyses. Furthermore, all the final products were screened for in‐vitro antibacterial activity against three Gram‐positive and three Gram‐negative bacteria and also tested for their inhibitory action against three strains of fungi. Compound IIc showed potent activity against all the bacterial (except S. typhimurium) and fungal strains. Especially, compounds IIi and IIj which have isoquinolyl and pyridyl substituents displayed potent antibacterial as well as antifungal activities compared to those of the respective standard drugs Ampicillin and Ketoconazole.

Synthesis of some new mono, bis-indolo[1, 2-c]quinazolines: evaluation of their antimicrobial studies

A convenient three-step strategy is proposed for the synthesis of mono and bis-indolo[1,2-c] quinazolines from 2-(2-aminophenyl)indole and various aryl aldehydes. The newly synthesized compounds were characterized by elemental analysis, IR, 1H NMR, 13C NMR, and mass spectroscopic investigation. All the derivatives were screened for antibacterial (S. aureus, B. subtilis, S. pyogenes, S. typhimurium, E. coli, K. pneumonia) and antifungal (A. niger, C. albicans, T. viridae) activities by cup plate method. Among the compounds tested, mono- indolo[1,2-c] quinazolines (15-18) exhibited good antibacterial activities while 15 and 18 also showed notable antifungal activity. Especially, 19 and 20 exhibited stronger antibacterial as well as antifungal activity against all tested strains.

Synthesis of mono, bis-2-(2-arylideneaminophenyl) indole azomethines as potential antimicrobial agents

A series of mono and bis 2-2-(arylidineaminophenyl)indole azomethines have been synthesized by a condensation reaction of 2-(2-amino phenyl) indole with various mono and diketones R-CO-Rl /R-CO-X-CO-Rl (1:1/2:1 ratio) in ethanol media. The synthesized azomethines were characterized via IR, 1H-NMR, 13C-NMR, MS and elemental analysis. The antimicrobial activity of these compounds against different bacteria and fungi was also evaluated.

Concentration and in situ detection of peptides using liquid matrix-assisted laser desorption ionization matrixes.

A ternary component system composed of alpha-cyano-4-hydroxycinnamic acid/3-aminoquinoline/quinoline (CHCA/3-AQ/Q; at a weight ratio of 1:4:4) was used as an extraction solvent as well as a liquid matrix for matrix-assisted laser desorption ionization (MALDI) mass spectrometry analysis. Peptides in aqueous solutions were extracted, concentrated, and prepared for MALDI analysis in one step. Extracting peptides in aqueous solutions was analogous to dispersive liquid-liquid microextraction and completed in less than 2 min because CHCA/3-AQ/Q was dispersed rapidly into the aqueous phase by ultrasonication during extraction. The detection limit for peptides in aqueous solutions was as low as 1.25 nM for angiotensin I. Protein digests obtained from conventional MALDI analysis and the proposed method were compared with respect to sequence coverage. The new approach was applied to sample cleanup, preconcentration, and in situ analysis of protein digests in signal suppressing agents such as Tris buffer and urea.

A review on the effects of current chemotherapy drugs and natural agents in treating non–small cell lung cancer

Lung cancer is the leading cause of cancer deaths worldwide, and this makes it an attractive disease to review and possibly improve therapeutic treatment options. Surgery, radiation, chemotherapy, targeted treatments, and immunotherapy separate or in combination are commonly used to treat lung cancer. However, these treatment types may cause different side effects, and chemotherapy-based regimens appear to have reached a therapeutic plateau. Hence, effective, better-tolerated treatments are needed to address and hopefully overcome this conundrum. Recent advances have enabled biologists to better investigate the potential use of natural compounds for the treatment or control of various cancerous diseases. For the past 30 years, natural compounds have been the pillar of chemotherapy. However, only a few compounds have been tested in cancerous patients and only partial evidence is available regarding their clinical effectiveness. Herein, we review the research on using current chemotherapy drugs and natural compounds (Wortmannin and Roscovitine, Cordyceps militaris, Resveratrol, OSU03013, Myricetin, Berberine, Antroquinonol) and the beneficial effects they have on various types of cancers including non-small cell lung cancer. Based on this literature review, we propose the use of these compounds along with chemotherapy drugs in patients with advanced and/or refractory solid tumours.

Memory effect in weakly-interacting Fe3O4 nanoparticles

This study addresses the issue of whether the magnetite Fe3O4 nanoparticle shows a true spin-glass like behavior or if this is an artifact of interparticle interaction. Transmission electron microscopy and X-ray diffraction pattern analysis confirms the formation of pseudospherical Fe3O4 nanoparticles with a grain size of 8(1) nm. The magnetic moment relaxation M(t) follows a stretched exponential and power law function, confirming the presence of multiple-magnetic anisotropic barriers (β = 0.51(1)) and weak-interparticle interaction (n = 0.60(4)). The observed field cooling (FC) memory effect occurs because of the presence of magnetic anisotropy arising from a broad size distribution and weak-interparticle interactions. The absence of the zero-field-cooled (ZFC) memory effect signals that the Fe3O4 nanoparticle system is not a true spin-glass system, and the observed decreasing behavior of magnetization in FC measurement is an artifact of the weak-interparticle interaction.

Ru(III)-catalyzed oxidation of pyridoxine and albuterol in pharmaceuticals

Ru(III) complexes with coordinated amide were synthesized and characterized by elemental, IR, mass, electronic, ESR spectral analysis, magnetic and conductance measurements and octahedral structures have been proposed. These complexes were used as catalysts for the oxidation of pyridoxine and albuterol in pharmaceuticals in presence of hydrogen peroxide. The role of co-oxidant and the effect of reaction time on the yields of oxidation products which were spectrophotometrically determined by condensing them with sulfanilic acid in acid medium were investigated. Structures of the oxidation products were established with the help of IR and NMR spectral analysis.

Study of microwave effects on the lipase-catalyzed hydrolysis.

The effect of microwave heating on lipase-catalyzed reaction remains controversial. It is not clear whether the reaction rate enhancements are purely due to thermal/heating effects or to non-thermal effects. Therefore, quantitative mass spectrometry was used to conduct accurate kinetic analysis of lipase-catalyzed hydrolysis of triolein by microwave and conventional heating. Commercial lipases from Candida rugosa (CRL), Porcine Pancreas (PPL), and Burkholderia cepacia (BCL) were used. Hydrolysis reactions were performed at various temperatures and pH levels, along with various amounts of buffer and enzymes. Hydrolysis product yields at each time point using an internal-standard method showed no significant difference between microwave and conventional heating conditions when the reaction was carried out at the same temperature. CRL showed optimum catalytic activity at 37 °C, while PPL and BCL had better activities at 50 °C. The phosphate buffer was found to give a better hydrolysis yield than the Tris-HCl buffer. Overall results prove that a non-thermal effect does not exist in microwave-assisted lipase hydrolysis of triolein. Therefore, conventional heating at high temperatures (e.g., 50 °C) can be also used to accelerate hydrolysis reactions.